Butyric acid, butyric acid salt or butyric acid derivative for the stimulation and / or disinhibition of the immune responses of plants and / or the treatment of plant infections

Abstract

The present invention relates to the use of butyric acid or a butyric acid derivative, or one of their salts, to for the stimulation and / or disinhibition of plant immune responses, and to a method for treating a plant infection comprising administering butyric acid or a butyric acid derivative, or one of their salts, and optionally at least one plant defence stimulator (PDS). The present invention also relates to a phytosanitary kit comprising butyric acid or a butyric acid derivative, or one of their salts, for the stimulation and / or disinhibition of plant immune responses. The present invention is particularly suitable for use in the pharmaceutical, phytopharmaceutical, agricultural, agri-food and chemical fields.

Description

[0001] BUTYRIC ACID, BUTYRIC ACID SALT OR BUTYRIC ACID DERIVATIVE FOR STIMULATING AND / OR DISINHIBITING PLANT IMMUNE RESPONSES AND / OR TREATING PLANT INFECTIONS

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention relates to the use of butyric acid or a butyric acid derivative, or one of their salts for the stimulation and / or disinhibition of plant immune responses. The present invention also relates to a method for treating a plant infection comprising the administration of butyric acid or a butyric acid derivative, or one of their salts and optionally at least one plant defense stimulator (PDS). The present invention also relates to a plant protection kit comprising butyric acid or a butyric acid derivative, or one of their salts for the stimulation and / or disinhibition of plant immune responses.

[0005] The present invention finds applications in particular in the pharmaceutical, phytopharmaceutical, agronomic, agri-food and chemical fields.

[0006] In the description below, the references in brackets ([ ]) refer to the list of references presented at the end of the text.

[0007] State of the art

[0008] The protection of plants, particularly crops, from infections by pathogens, such as fungi, oomycetes, bacteria and / or viruses, is a constant concern in the agricultural sector. Plant immunity is the subject of much research, both fundamentally to decipher its mechanisms and applied to exploit it in crop protection strategies. There is indeed a strong demand for alternative solutions to synthetic pesticides or other fungicides such as copper and sulfur, such as biocontrol products (including PDS: Plant Defense Stimulators), for environmental and health reasons.

[0009] As part of the Ecophyto plan, approaches have been taken to reduce the doses of pesticides used in agriculture, with the use of SDPs capable of activating the plant's immune system, and thus making it more tolerant or even resistant to various biotic stresses. However, the numerous trials conducted to date, particularly in Chambers of Agriculture and Technical Institutes, have demonstrated insufficient effectiveness, which is difficult to reproduce.

[0010] Therefore, there is a real need to find a way to advantageously induce plant resistance to pathogens with good efficiency and good reproducibility.

[0011] In this approach, plant extracts or mineral substances were used without identifying a possible "active ingredient", and / or "active ingredients" with little or no penetration. SDPs, unlike contact pesticides, must pass through the cuticular barrier and cell walls to induce the plant's defense responses.

[0012] Also, there is a real need to find a way to advantageously induce resistance in plants to pathogens with good efficiency and sufficient reproducibility, in particular with compounds capable of passing through the cuticular barrier and the cell walls of plant cells.

[0013] Hydrophilic compounds such as carbohydrate polymers or proteins have been used. While these compounds are effective when used under controlled conditions and / or injected directly into the leaves of the plants to be treated, they are ineffective or have insignificant efficacy when used in the open field.

[0014] Also, there is a real need to find a way to advantageously induce plant resistance to pathogens with good efficiency and good reproducibility, particularly when used in open fields. It is also known that the activation of plant immune responses is mainly dependent on the activation of specific signaling pathways: production of reactive forms of oxygen, nitric oxide (NO), post-translational modifications of proteins, activation of defense genes, etc. These pathways are activated after perception of molecular patterns of the MAMP (Microbe Associated Molecular Pattern) or DAMP (Damage Associated Molecular Pattern) type by PRR (Pattern Recognition Receptors) type receptors; Jones and Dangl, 2006 [1]).A description of defense responses has been carried out in tobacco and grapevine (Garcia-Brugger et al. 2006 [2], Héloir et al. 2019 [3]) and an identification of different SDPs and receptors (Krzyzaniak et al. 2018 [4], Brulé et al. 2019 [5]) has also been carried out.

[0015] Many MAMP or DAMP-type SDPs are known and can be used to induce plant resistance to pathogens under controlled conditions. However, the effectiveness of these compounds remains limited, particularly when used in open fields.

[0016] Therefore, there is a real need to find a way to advantageously induce plant resistance to pathogens with good efficiency.

[0017] It has also been shown that the intensity of plant immune responses is also dependent, in addition to the mechanisms of action described above, on the derepression of these same responses. It has been shown that a family of plant-specific histone deacetylases (HDACs), type-2 HDACs or HD2 (Grandperret et al. 2013 [6], Nicolas-Francès et al. 2018 [7]), are negative regulators of the intensity of plant defense responses (Bourque et al. 2011-2016 [8-9]). They participate in the epigenetic mechanisms of gene expression regulation by deacetylating histones, promoting the transition from hetero- to euchromatin and allowing the regulation of target gene expression.

[0018] However, known SDPs have demonstrated limited efficacy, particularly in protecting plants from pathogens and / or infections, or in stimulating plant immune responses. In particular, known SDPs have demonstrated limited or even insignificant efficacy, particularly when used in open fields.

[0019] Therefore, there is a real need to find a way to advantageously induce plant resistance, particularly to pathogens, with good efficiency. There is also a real need to find a way to advantageously treat plant infections with good efficiency.

[0020] Statement of the invention

[0021] The present invention aims precisely to meet these needs through the use of butyric acid or a butyric acid derivative, or one of their salts.

[0022] The inventors have demonstrated in a surprising and unexpected manner that the use of butyric acid or a butyric acid derivative, or one of their salts, advantageously and surprisingly allows the immune response of plants to be stimulated.

[0023] The inventors have also surprisingly demonstrated that butyric acid or a butyric acid derivative, or one of their salts, advantageously and surprisingly allows disinhibition of the immune responses of plants.

[0024] The inventors have demonstrated that butyric acid or a butyric acid derivative, or one of their salts, advantageously inhibits histone deacetylases (HDAC).

[0025] Furthermore, the inventors have surprisingly demonstrated that butyric acid or a butyric acid derivative, or one of their salts, optionally combined with at least one SDP, advantageously allows the targeted activation of genes involved in immune responses.

[0026] Furthermore, the inventors have surprisingly demonstrated that butyric acid or a butyric acid derivative, or one of their salts, optionally combined with at least one SDP, makes it possible to treat any infection regardless of the pathogen. In particular, the inventors have demonstrated that the present invention, through the activation of genes involved in immune responses and / or the inhibition of HDACs, in particular type 2 HDACs, allows an increase in the immune responses of plants and advantageously a treatment of infections regardless of the pathogen responsible.

[0027] Furthermore, the inventors have surprisingly demonstrated that butyric acid or a butyric acid derivative, or one of their salts, combined with at least one SDP, makes it possible to treat any infection regardless of the pathogen. In particular, the inventors have demonstrated that the present invention, through the activation of genes involved in immune responses and / or the inhibition of HDACs, in particular type 2 HDACs, allows an increase in the immune responses of plants and advantageously a treatment of infections regardless of the pathogen responsible.

[0028] The present invention also relates to the use of butyric acid or a butyric acid ester or a hydroxybutyric acid, or one of their salts and at least one plant defense stimulator (PDS) for the stimulation and / or disinhibition of a plant immune response.

[0029] As used herein, "butyric acid" means a compound of formula (CH3-CH2-CH2-COOH).

[0030] As used herein, "butyric acid derivative" means any derivative known to those skilled in the art. For example, it may be a butyric acid ester or a hydroxybutyric acid. For example, it may be a butyric acid ester selected from methyl and ethyl ester. As used herein, the term "salt" refers to phytophysiologically acceptable salts, for example suitable for phytosanitary use without toxicity, irritation, allergic response or other deleterious effect unsuitable for use, for example in agriculture.

[0031] In this document, the term "butyric acid salt" means any butyric acid salt known to those skilled in the art and commercially available. This may be, for example, a sodium, calcium or potassium salt of butyric acid, preferably a sodium salt of butyric acid. This may be, for example, sodium butyrate. This may be sodium butyrate marketed by Carl Roth GmbH + Co KG under the trade name Sodium butyrate >98%. Preferably, the "butyric acid salt" is sodium butyrate.

[0032] In this document, the term "salt of butyric acid derivative" means any salt of butyric acid known to those skilled in the art. It may be, for example, a sodium, calcium or potassium salt of a butyric acid derivative. It may be, for example, a sodium, calcium or potassium salt of a butyric acid ester. It may be the methylbutyrate marketed by Carl Roth GmbH + Co KG under the trade name ROTICHROM® CPG methyl butyrate. It may be, for example, the ethylbutyrate marketed by Carl Roth GmbH + Co KG under the trade name ROTICHROM® CPG ethyl butyrate. It may also be, for example, a sodium, calcium or potassium salt of hydroxybutyric acid. It may be, for example, sodium 3-hydroxybutyrate. This may be a sodium salt of hydroxybutyric acid marketed by Carl Roth GmbH + Co KG under the trade name DL-3-hydroxy butyric acid sodium salt >98%.

[0033] In this document, by stimulation of immune responses is meant an increase in the intensity of immune responses to a pathogenic agent, for example by inhibition of type 2 HDACs or HD2 and / or stimulation of the expression of genes, for example the genes STS (for Stilbene synthase, NCBI Reference: XM_003634017.4), PAL (for Phenylalanine amonia lyase, NCBI Reference: XM_002281763.5) and PR-3 (for Pathogenesis related-3, NCBI Reference: NM_001281244.1) and / or an activation of MAPKs for Mitogen-Activated Protein Kinase.

[0034] In this context, disinhibition of immune responses means an increase in the intensity of immune responses to a pathogen, for example by inhibition of type 2 HDACs or HD2.

[0035] In this document, a plant is understood to mean any plant known to those skilled in the art. It may be any living plant fixed in the soil and whose upper part flourishes in the air or in fresh water. It may, for example, be plants that have been modified by selection, mutagenesis or genetic engineering. Genetically modified plants are plants whose genetic material has been modified by the use of recombinant DNA techniques. The use of recombinant DNA techniques makes possible modifications that cannot easily be obtained by crossbreeding under natural circumstances, mutations or natural recombination.

[0036] As used herein, "plant" may also refer to any living plant grown above ground. As used herein, "plant cultivation above ground" means any method of growing plants above ground known to those skilled in the art. This may be a plant grown, for example, aeroponics, hydroponics and / or on a growing medium, for example, rock wool. Examples include plants that have been modified by selection, mutagenesis or genetic engineering. Genetically modified plants are plants whose genetic material has been modified by the use of recombinant DNA techniques. The use of recombinant DNA techniques makes possible modifications that cannot easily be achieved by crossbreeding under natural circumstances, mutations or natural recombination.

[0037] In this invention, the plants may be chosen, for example, from the group comprising monocotyledons and dicotyledons.

[0038] In this context, plants may be, for example, "agricultural plants", for example, plants some or all of which (such as seeds) are harvested or grown commercially or which serve as an important source of food, feed, fiber (e.g., cotton, flax), fuel (e.g., wood, bioethanol, biodiesel, biomass) or other chemical compounds. Agricultural plants may also include horticultural plants, i.e., plants grown in gardens (not fields), for example, certain fruits and vegetables. Agricultural plants may be, for example, cereals, for example, wheat, rye, barley, triticale, oats, sorghum or rice, beetroot, for example, sugar beet or fodder beet;fruit plants or fruits, such as pome fruits, stone fruits or soft fruits, for example grapes, apples, pears, plums, peaches, almonds, cherries, strawberries, raspberries, blackberries or gooseberries; leguminous plants, for example lentils, peas, alfalfa or soybeans; oil plants, such as rapeseed, canola, flax, mustard, olives, sunflower, coconut, cocoa beans, castor oil plants, oil palms, peanuts or soybeans; cucurbits, for example squash, cucumbers or melons; fibre plants, for example cotton, flax, hemp or jute; citrus fruits, for example oranges, lemons, grapefruit or mandarins; vegetables, such as spinach, lettuce, asparagus, cabbage, carrots, onions, tomatoes, potatoes, cucurbits or paprika;Lauraceae plants, for example avocado, cinnamon or camphor; energy plants and raw materials, such as corn, soybeans, rapeseed, canola, sugar cane or oil palm; tobacco; hazelnuts; coffee; tea; bananas; vines, for example table grapes and grape juice vines; hops; grass; natural rubber plants or ornamental and forestry plants, for example flowers, shrubs, broad-leaved trees or conifers, for example conifers.;

[0039] These may be fruit crops, for example apples, strawberries, grapes and / or citrus fruits, for example oranges and lemons.

[0040] Examples include brassicas, e.g. Arabidopsis thaliana. Examples include agricultural plants grown in open fields, e.g. potatoes, sugar beets, cereals such as wheat, rye, barley, oats, sorghum, rice, maize, cotton, rapeseed, oilseed rape and canola, legumes e.g. soybeans, peas and field beans, sunflowers, sugar cane; ornamental plants; or vegetables, e.g. cucumbers, tomatoes or onions, leeks, lettuce, squash. These may be woody plants, for example native woody species, Vitis vinifera vine varieties, for example cultivated for the production of table or wine grapes, for example a Vitis vinifera grape variety chosen from abundant, abouriou, aléatico, alicante henri bouschet, aligoté, alphonse lavallée, altesse, alvarinho, araignan, aramon, gray aramon, aramon, aranel, arbane, arinarnoa,arriloba, arrouya, arrufiac, arvine, aubin, aubin vert, aubun, auxerrois, bachet, baco, barbaroux, baroque, béclan, béquignol, biancu gentile, dame, blanqueiron, bouchalès, bouillet, bouquettraube, bourboulenc, button, brown, brown, silver forca, cabernet-franc, cabernet-sauvignon, caladoc, calitor, camaralet, carcajolo, carcajolo, cardinal rouge, carignan, carmenère, castets, césar, chambourcin, Chardonnay, chasan, chasselas, chatus, chenanson, chenin, cinsaut, clairette, clairette, clavarita, colodi, colodi colombard, corbeau, cot, couderc, counoise, courbu, couston, crouchen, danlas, duras, durit, egiodola, ekigaïna, elbling, etraire de la dui, ferradou, fer-servadou, feunate, florental, folignan, folle he, franc de haute-saône, fuella nera, gauzet, gauzet, gauzet, gauze gamay de chaudenay, gamay fréaux, gamay, ganson, garonnet, gascón, genovese, gewurztraminer, goldriesling, gouget, graisse, gramon, grassen, grenache, grenache gris, grenache, gringet,grolleau gris, grolleau, gros manseng, gros vert, jacquère, joubertin, jurançon, knipperlé, landal, lauzet, len de l'el, léon millot, liliorila, listan, lival, lledoner pelut, macabeu, mancin, manseng, marshal foch, marsanne, marelanne, mauzaquin, mézac, mézac, mayor melon, merille, merlot, merlot, meslier saint-françois, meunier, milgranet, molette, mollard, mondeuse he, mondeuse, monerac, montils, mornen, morrastel, mourvaison, mourvèdre, mouyssaguès, müller-thurgau, muresconu, nutmeg, nutmeg, nutmeg, grapefruit small red nutmeg, small-grain nutmeg, ash nutmeg, nutmeg of Alexandria, nutmeg of Hamburg, autumn nutmeg, négret de banhars, négrette, nielluccio, florien, Oberlin, ondenc, orbois, pagadebiti, pani nutmeg, parellada, pastry, petit, brunch, small courbu, petit manseng, petit meslier, petit verdot, picardan, pineau d'aunis, pinot, pinot gris, pinot, piquepoul, piquepoul gris, piquepoul, brunel plant, straight plant, plantet,portan, portuguese blue, poulsard, precocious bousquet, precocious de malingre, prunelard, raffiat de moncade, ravat, golden rayon, ribol, riesling, riminèse, rivairenc, rivairenc gris, rivairenc, romorantin, du var, roublot, roussanne, roussette d'ayze, rubilande, sacy, saint-côme, saint-macaire, saint-pierre doré, sauvignon, sauvignon gris, savagnin, savagnin, sciaccarello, ségalin, sei, select, semebat, sémillon, servanin, serving, seyval, sylvaner, syrah, tannat, tempranillo, téoulier, terret, terret gris, terret, tibouren, tourbat, tressot, trousseau gris, trousseau, ugni, valdiguié, valérien, varousset, early red velteliner, verdelho, verdesse, vermentino, villard, viognier. These may also be varieties resulting from intra- or interspecific hybridization programs and / or selected for their genetic resistance, for example, to biotic or abiotic stresses. These may include, for example, the varieties Artaban, Floréal, Vidoc, Voltis, Coliris, Lilaro, Opalor,Sirano or Selenor. These may be varieties obtained by a process including intra- or interspecific hybridization and optionally selection, for example as described by Schneider et al. 2019

[0010] ,

[0041] These may be "Forestry plants" for example trees, for example trees used in reforestation or industrial plantations. These may be for example conifers, for example pines, especially Pinus spec, fir and spruce, eucalyptus, tropical trees such as teak, rubber tree, oil palm, willow (Salix), especially SaNx spec, poplar (cottonwood), especially Populus, spec, beech, especially Fagus spec, birch and oak. These may be an ornamental plant, for example plants commonly used in gardening, for example in parks, gardens and on balconies. Examples are turf, geranium, pelargonia, petunia, begonia, pelargonium.

[0042] The inventors have also demonstrated in a surprising and unexpected manner that butyric acid or a butyric acid derivative, or one of their salts, optionally combined with at least one SDP, advantageously allows the treatment of plant infections.

[0043] The present invention also relates to the use of butyric acid or a butyric acid derivative, or one of their salts, for the treatment of a plant infection.

[0044] The inventors have also demonstrated in a surprising and unexpected manner that butyric acid or a butyric acid derivative, or one of their salts, combined with at least one SDP, advantageously allows the treatment of plant infections.

[0045] The present invention also relates to the use of butyric acid or a butyric acid derivative, or one of their salts and at least one plant defense stimulator (PDS) for the treatment of a plant infection.

[0046] As used herein, by "treatment" is meant, for example, at least one application of the composition of the invention, for example in a form as described above, capable of preventing or stopping an infection, for example by stopping the growth of the pathogenic agent and / or by killing the pathogenic agent.

[0047] In this document, the term "pathogenic agent" means an agent selected from the group comprising fungi, oomycetes, bacteria, phytoplasmas, viruses and yeasts. This may be, for example, the fungi Phaeomoniella chlamydospora, Phaeocremonium aleopholilum, Fomitiporia mediterranea, Strereum hirsutum, Phellinus igniarius, Eutypa lata, Botryosphaeria obtusa, Neofusicoccum parvum, Botryosphaeria dothidea, Botryosphaeria stevensii, Phomopsis viticole, Botrytis cinerea, Erysiphe necator, Guignardia bidwellii, or the oomycete Plasmopara viticola. Preferably Plasmopara viticola and / or Erysiphe necator. This may be, for example, Hyaloperonospora arabidopsidis N0C02

[0048] The present invention also relates to a composition comprising butyric acid or a butyric acid derivative, and / or one of their salts. This may be, for example, a composition for agricultural use, a composition for veterinary use, a medical composition. This may be, for example, a phytosanitary composition.

[0049] Herein, the composition may be in any form known to those skilled in the art, for example suitable for agricultural use. For example, the composition may be in a liquid form, an emulsion, an ointment, a foam, a paste, a powder or a gel.

[0050] In the present invention, the composition may be manufactured by any method known to those skilled in the art. It may be, for example, a simple mixture, preferably leading to a homogeneous composition.

[0051] For the purposes of this description, the term "effective amount" means an amount sufficient to obtain the desired effect, in particular to enable stimulation of plant immune responses and / or disinhibition of plant immune responses and / or a reduction or disappearance of plant diseases and / or infection.

[0052] In the present invention the concentration of butyric acid or butyric acid derivative, or one of their salts in the phytosanitary composition may be from 1 to 10 mM, for example from 1 to 2 mM, preferably 2 mM.

[0053] In the present the concentration of butyric acid or butyric acid derivative, or one of their salts in the phytosanitary composition may be between 0.10 and 1.1 gL' 1 ' for example 0.11 to 1.1 g.L' 1 , for example from 0.1 1 to 0.40 gL' 1 , for example from 0.20 to 0.30 gL' 1 , for example equal to 0.22 gL- 1 .

[0054] In the present invention, the phytosanitary composition may further comprise at least one plant defense stimulator (PDS). This may be any compound known to those skilled in the art capable of activating the natural defense mechanisms of plants. It may, for example, be a compound recognized by plants as an initial signal of an attack, or as an alert signal intervening in the signaling cascade. It may, for example, be a compound of natural or synthetic origin in accordance with the regulations on the placing of plant protection products on the market: EC Regulation No. 1107 / 2009 or Regulation 2023 / 121. It may be any PDS compound known to those skilled in the art and commercially available.This could be, for example, a plant defense-stimulating compound referenced in the "e-phy" plant protection product catalog of the French National Agency for Food, Environmental and Occupational Health and Safety (ANSES) or in the "EPPO A1 list" and "EPPO A2 list" catalogs of the European and Mediterranean Plant Protection Organization (EPPO). This could be, for example, COS-OGA, the active ingredient of Messager marketed by the company Cérience, or ABE IT 56, the active ingredient of Belvine marketed by the company Cérience.

[0055] In the present the concentration of said at least one plant defense stimulator (PDS) in the phytosanitary composition may be between 0.01 and 4 gL' 1 , for example from 0.05 to 4 gL' 1 , for example from 0.01 to 3.25 gL' 1 , for example from 0.0254 to 3.25 gL' 1 , for example from 0.01 to 0.80 gL' 1, for example from 0.01 to 0.025 gL' 1 , for example from 1 to 3.25 gL' 1 . For example, when said at least one plant defense stimulator (PDS) is COS-OGA, the concentration in the phytosanitary composition may be between 0.01 and 0.025 gL' 1 . For example, when said at least one plant defense stimulator (PDS) is ABE IT 56 the concentration in the phytosanitary composition may be between 1 and 3.25 gL' 1 . For example, when said at least one plant defense stimulator (PDS) is ABE IT 56 the concentration in the phytosanitary composition may be for example from 0.1 to 0.80 gL' 1 , for example equal to 0.75 gL' 1 .

[0056] In the present invention, the composition may comprise one or more fertilizing materials, which may be of various natures, for example urea, ammonium sulfate, natural phosphate, potassium chloride, ammonium sulfate, magnesium nitrate, manganese nitrate, zinc nitrate, copper nitrate, phosphoric acid, and / or boric acid.

[0057] The composition may further comprise at least one pesticide. This may be pesticide(s) chosen from insecticides, fungicides, herbicides, parasiticides. This may be, for example, a pesticide referenced in the “e-phy” catalogue of phytopharmaceutical products of the French National Agency for Food, Environmental and Occupational Health Safety (ANSES) or in the “EPPO A1 list” and “EPPO A2 list” catalogues of the European and Mediterranean Plant Protection Organization (EPPO). For example, the composition according to the invention may comprise one or more fungicides chosen from copper and sulfur. This may be, for example, commercially available pesticides, for example pesticides, for example synthetic, for example chemical, for which a Marketing Authorization (MA) has been issued.This could be, for example, Kocide 2000 marketed by COSACO GmbH, or Heliosoufre marketed by Action Pin. A person skilled in the art will be able to choose the pesticide(s) most suited to the plant to be treated.

[0058] In the present invention, when used according to the invention, the composition can be supplied to the plant by foliar or root route, preferably by foliar route.

[0059] In this the plant defense stimulator (PDS) may be included in a phytosanitary composition.

[0060] Preferably the composition, preferably phytosanitary, comprises butyric acid or sodium butyrate and at least one plant defense stimulator (PDS).

[0061] The present invention also relates to a method for treating a plant infection comprising the steps of: a) administering butyric acid or a butyric acid derivative, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts, b) administering at least one plant defense stimulator (PDS), in which the administration of butyric acid or a butyric acid derivative, or one of their salts is prior to, simultaneous with or concomitant with the administration of at least one plant defense stimulator.

[0062] The present invention also relates to a method for treating a plant infection comprising the steps of: a) administering butyric acid or sodium butyrate or a phytosanitary composition comprising butyric acid or sodium butyrate, and b) administering at least one plant defense stimulator (PDS) or a composition, preferably phytosanitary, comprising at least one plant defense stimulator (PDS), in which the administration of butyric acid or sodium butyrate or a phytosanitary composition comprising butyric acid or sodium butyrate is prior to, simultaneous with or concomitant with the administration of at least one plant defense stimulator (PDS) or a phytosanitary composition comprising at least one plant defense stimulator (PDS).

[0063] Butyric acid or a butyric acid derivative, or one of their salts is as defined above.

[0064] The phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts is as defined above

[0065] Plant Defense Stimulator (PDS) is as defined above.

[0066] In this the plant defense stimulator (PDS) may be included in a phytosanitary composition.

[0067] In the present invention, the step of administering and / or applying butyric acid or a butyric acid derivative, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts to the plant may be carried out by any suitable method and / or means known to those skilled in the art. For example, the application may be carried out by sprinkling the plant, watering, misting, brushing, immersing, dusting.

[0068] Herein, the administration and / or application of butyric acid or a butyric acid derivative, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts to the plant can be carried out, with various devices, for example with any type of agricultural sprayer known to those skilled in the art. Those skilled in the art will easily be able to determine the type of sprayer that may be used, for example it may be a hand-held pneumatic sprayer. It may be, for example, a Berthoud brand backpack sprayer, marketed under the commercial reference Cosmos 18.

[0069] Herein, the administration and / or application of butyric acid or a butyric acid derivative, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts to the plant may be carried out in order to maintain a constant quantity of butyric acid or a butyric acid derivative, or one of their salts or said composition at the plant level, for example the application may be carried out at least once a month, once a week, or once a day. Those skilled in the art will easily be able to adapt the application of the composition according to the plant and / or the constant quantity to be maintained.

[0070] In the present, the volume of phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts administered and / or applied to an agricultural area comprising the plant may be between 50 and 500 L.ha'1 , for example from 100 to 300 L.ha _

[0071] 1 In this document, "agricultural area" means land used or intended for the cultivation of plants. This may include, for example, land cultivated for the cultivation and / or production of plants.

[0072] Herein, the volume of phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts administered and / or applied may be from 10 to 400 ml per plant, for example from 100 to 300 ml per plant.

[0073] In the present invention, the step of administering and / or applying at least one plant defense stimulator (PDS) to the plant may be carried out by any suitable method and / or means known to those skilled in the art. For example, the application may be carried out by spraying the plant, watering, misting, brushing, immersing, dusting.

[0074] In the present invention, the step of administering and / or applying a phytosanitary composition comprising at least one plant defense stimulator (PDS) to the plant may be carried out by any suitable method and / or means known to those skilled in the art. For example, the application may be carried out by spraying the plant, watering, misting, brushing, immersing, dusting.

[0075] In the present invention, the administration and / or application of at least one plant defense stimulator (PDS) to the plant can be carried out, with various devices, for example with any type of agricultural sprayer known to those skilled in the art. Those skilled in the art will easily be able to determine the type of sprayer that can be used, for example it may be a hand-held pneumatic sprayer. It may be, for example, a Berthoud brand backpack sprayer, marketed under the commercial reference Cosmos 18.

[0076] In the present invention, the administration and / or application of at least one phytosanitary composition comprising a plant defense stimulator (PDS) to the plant can be carried out, with various devices, for example with any type of agricultural sprayer known to those skilled in the art. Those skilled in the art will easily be able to determine the type of sprayer that can be used, for example it may be a hand-held pneumatic sprayer. It may be, for example, a Berthoud brand backpack sprayer, marketed under the commercial reference Cosmos 18.

[0077] Herein, the volume of said at least one plant defense stimulator (PDS) and / or the phytosanitary composition comprising at least one plant defense stimulator (PDS) administered and / or applied to an agricultural area comprising the plant may be from 50 to 500 L.ha' 1 , for example from 100 to 300 L.ha -1 .

[0078] Herein, the volume of said at least one plant defense stimulator (PDS) and / or phytosanitary composition at least one plant defense stimulator (PDS) administered and / or applied to a plant may be from 10 to 400 ml per plant, for example from 100 to 300 ml per plant.

[0079] Herein, the administration and / or application of at least one plant defense stimulator (PDS) and / or the phytosanitary composition at least one plant defense stimulator (PDS) to the plant can be programmed, for example via an automatic programming device with daily, weekly, monthly application.

[0080] Herein, the administration and / or application of at least one plant defense stimulator (PDS) and / or the phytosanitary composition at least one plant defense stimulator (PDS) to the plant may be carried out in order to maintain a constant amount of composition at the plant level, for example the application may be carried out at least once a month, once a week, or once a day. Those skilled in the art will easily be able to adapt the application of the composition according to the plant and / or the constant amount to be maintained.

[0081] In this document, the plant is as defined above.

[0082] Herein, when the administration and / or application of butyric acid or a butyric acid derivative, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts and said at least one plant defense stimulator (PDS) or phytosanitary composition at least one plant defense stimulator (PDS) are successive, the dosage for each administration may be an administration and / or application of butyric acid or a butyric acid derivative, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts followed by the administration of said at least one plant defense stimulator (PDS) or phytosanitary composition at least one plant defense stimulator (PDS).For example, said at least one plant defense stimulator (PDS) or a phytosanitary composition at least one plant defense stimulator (PDS) may be administered immediately, i.e. concomitantly, or for example from 1 minute to a few hours, for example from 1 minute to 48 hours, preferably from 5 minutes to 24 hours, preferably from 1 to 3 hours after the administration and / or application of butyric acid or a butyric acid derivative, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts.

[0083] In other words, even if in the present description reference is made to a composition, it is understood that each of the compounds of the composition can be administered concomitantly with the other compounds (for example in a single composition or in two compositions, each of these compositions comprising one or more of the aforementioned components, the mode of administration of each of the compounds or composition(s) being able to be identical or different), or independently of each other, for example successively.

[0084] The present invention also relates to a phytosanitary kit intended to be used for the stimulation and / or disinhibition of the immune response of plants and / or the treatment of a plant infection comprising: i. a butyric acid or a butyric acid derivative, or one of their salts, or a phytosanitary composition comprising a butyric acid or a butyric acid derivative, or one of their salts and ii. at least one plant defense stimulator (PDS), or a composition, preferably phytosanitary, comprising at least one plant defense stimulator (PDS).

[0085] Butyric acid or a butyric acid derivative, or one of their salts is as defined above. For example, the kit may comprise butyric acid or a butyric acid derivative, or one of their salts usable by spraying a phytosanitary composition comprising from 1 to 10 mM of said butyric acid or butyric acid derivative, or one of their salts.

[0086] The plant defense stimulator (PDS) is as defined above. For example, the kit may comprise said plant defense stimulator (PDS) usable by spraying a composition comprising said plant defense stimulator (PDS) within 0 minutes to 48 hours, for example 5 minutes to 24 hours, preferably 1 to 3 hours, preferably 2 hours, after the first spraying of said butyric acid or butyric acid derivative, or one of their salts. Herein, when said composition comprising said plant defense stimulator (PDS) is sprayed within 0 minutes after the first spraying of said butyric acid or butyric acid derivative, or one of their salts, the spraying of said composition and said butyric acid or butyric acid derivative, or one of their salts are concomitant.

[0087] In the present invention, the kit may comprise a support comprising instructions for the use of said butyric acid or a butyric acid derivative, or one of their salts, and said at least one plant defense stimulator. The support comprising instructions for the use of said butyric acid or a butyric acid derivative, or one of their salts, and said at least one plant defense stimulator according to the invention may be a manual or a leaflet which may have the function, in particular, of explaining to the user the manner and frequency of application.

[0088] The phytosanitary kit may also include an applicator, for example a dynamic applicator, for example manual or electric.

[0089] The present invention also relates to a combination comprising: a composition, preferably phytosanitary, comprising a butyric acid or a butyric acid derivative, or one of their salts, and a composition, preferably phytosanitary, comprising at least one plant defense stimulator (PDS).

[0090] The composition comprising butyric acid or a butyric acid derivative, or one of their salts is as defined above

[0091] The composition comprising at least one plant defense stimulator (PDS) is as defined above.

[0092] In the present, when the administration and / or application of the compositions of the combination may be simultaneous or concomitant or successive. For example when the administration and / or application of a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts and of the phytosanitary composition at least one plant defense stimulator (PDS) are successive, the dosage for each administration may be an administration and / or application of butyric acid or a butyric acid derivative, or one of their salts or of a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts followed by the administration of said at least one plant defense stimulator (PDS) or of a phytosanitary composition at least one plant defense stimulator (PDS).For example, said at least one plant defense stimulator (PDS) or a phytosanitary composition at least one plant defense stimulator (PDS) may be administered immediately, i.e. concomitantly, or for example from 1 minute to a few hours, for example from 1 minute to 48 hours, preferably from 5 min to 24 hours, preferably from 1 to 3 hours after the administration and / or application of butyric acid or a butyric acid derivative, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid derivative, or one of their salts.

[0093] For example, the plant defense stimulator (PDS) or composition, preferably phytosanitary, comprising at least one plant defense stimulator (PDS) may be applied, for example by spraying the plant defense stimulator (PDS) or a composition comprising said plant defense stimulator (PDS) within 0 minutes to 48 hours, for example 5 minutes to 24 hours, preferably 1 to 3 hours, preferably 2 hours, after the first application, for example by spraying said butyric acid or butyric acid derivative, or one of their salts or the phytosanitary composition comprising butyric acid or butyric acid derivative, or one of their salts.In the present, when said composition, preferably phytosanitary, comprising said plant defense stimulator (PDS) is sprayed within 0 minutes after the first spraying of said butyric acid or butyric acid derivative, or one of their salts, the spraying of said composition and said butyric acid or butyric acid derivative, or one of their salts are concomitant.

[0094] Other advantages may still become apparent to those skilled in the art upon reading the examples below, illustrated by the attached figures, given for illustrative purposes.

[0095] Brief description of the figures

[0096] Figure 1: Figure 1 represents a diagram and a photograph of the typical morphology of a cutting used in the tests cited in the examples. The different ranks designate the leaf number starting from the apex of the cutting. Ranks 1 and 2 designate the leaves used in the tests. Leaves ranks 0, 3, 4 and the apex were not taken into account in the study. Figure 2: Figure 2 represents a chronological timeline of the experimental protocol implemented in the tests of the examples. Figure (1 / 2) illustrates the so-called pretreatment approach. That is to say, the disinhibitory molecule was applied X hours before the SDP, X can vary from 2 to 48 h. The reference D-2 represents the day of application of the SDP. The reference JO corresponds to the infection of the plants by P. viticola or E. necator. D+5 corresponds to the 5th day, when leaf discs were collected. Disease symptoms were measured at D+6 for downy mildew (P.viticola) or D+20 for powdery mildew (E. necator). Figure 2 (2 / 2) illustrates the case where the disinhibitory molecule and the SDP were applied simultaneously, i.e. the same solution contained both molecules which were sprayed 2 days before the plants were infected.

[0097] Figure 3: Figure 3 represents a histogram showing the effectiveness of the protection induced against P. viticola (in %), the agent of grapevine downy mildew, as a function of the treatments carried out. 6 different treatments were tested (from left to right):

[0098] - Control (treatment with water)

[0099] - Goal (treatment with 1 mM sodium butyrate alone on day JO)

[0100] - COS-OGA 12.5 (treatment with half a dose of COS-OGA at 12.5 mg.L- 1 The approved dose for field treatments is 25 mg. 1 )

[0101] - Pretreatment. But / COS-OGA (pretreatment for 48 h with 1 mM sodium butyrate then treatment with a dose of COS-OGA 12.5 mg.L 1 )

[0102] - Co-treatment. But / COS-OGA (simultaneous treatment with 1 mM sodium butyrate and a dose of COS-OGA 12.5 mg.L- 1 . Both molecules are dissolved in the same solution)

[0103] - COS-OGA 25 5 (treatment with a full dose of COS-OGA at 25 mg.L' 1 )

[0104] Values ​​were normalized to control (Ctle).

[0105] The values ​​presented are the average of five independent experiments and were expressed as the percentage of induced protection, with 100% induced protection corresponding to a total absence of P. viticola development.

[0106] Figure 4: Figure 4 represents a histogram showing the effectiveness of the protection induced against E. Necator (in %), the agent of powdery mildew in grapevines, according to the treatments carried out. 6 different treatments were tested (from left to right):

[0107] - Ctle (Control, treatment with water)

[0108] - COS-OGA 12.5 (treatment with half a dose of COS-OGA at 12.5 mg.L- 1 The approved dose for field treatments is 25 mg. 1 )

[0109] - Goal (treatment with 1 mM sodium butyrate alone on day JO)

[0110] - Pretreatment. But / COS-OGA (pretreatment for 48 h with 1 mM sodium butyrate then treatment with a dose of COS-OGA 12.5 mg.L 1 )

[0111] - ABE-IT 56 (treatment with 3.25 gL' 1 of ABET-IT 56, active ingredient of Belvine)

[0112] - Pretreatment. But / ABE-IT 56 (pretreatment for 48 h with 1 mM sodium butyrate then with a dose of 3.25 gL' 1 of ABET-IT 56, active ingredient of Belvine)

[0113] Values ​​were normalized to control (Ctle).

[0114] The values ​​presented are the average of five independent experiments and were expressed as the percentage of induced protection, with 100% induced protection corresponding to a complete absence of E. Necator development.

[0115] Figure 5: Figure 5 shows a histogram showing the protection induced against E. necator, the agent of grapevine powdery mildew, by treating the plant with ABE-IT 56 (active ingredient of Belvine) and sodium butyrate and butyrate esters, namely methyl butyrate and ethyl butyrate. These values ​​are representative of two independent experiments.

[0116] Results obtained with butyrate esters, namely methyl- and ethyl-butyrate. 6 treatments were applied (from left to right):

[0117] - Control (treatment with water) - Goal (treatment with 1 mM sodium butyrate alone on day JO)

[0118] - ABE-IT 56 (treatment with a dose of 3.25 gL' 1 of ABE-IT 56, active ingredient of Belvine)

[0119] - Pretreatment. But / ABE-IT 56 (pretreatment for 48 h with 1 mM sodium butyrate then with a dose of 3.25 gL' 1 of ABE-IT 56)

[0120] - Pretreatment. MeBut / ABE-IT 56 (pretreatment for 48 h with 1 mM methyl-butyrate then with a dose of 3.25 gL' 1 of ABE-IT 56)

[0121] - Pretreatment. EtBut / ABE-IT 56 (pretreatment for 48 h with 1 mM ethyl-butyrate then with a dose of 3.25 gL' 1 of ABE-IT 56)

[0122] Figure 6: Figure 6 represents a histogram showing the protection induced against H. aradibopsidis N0C02, the agent of Arabidopsis downy mildew, in response to ABE-IT 56 (active ingredient of Belvine) and COS-OGA (active ingredient of Messenger) and to pretreatment with sodium butyrate. These values ​​are representative of two independent experiments. The treatment modalities were (from left to right):

[0123] - Ctle (treatment with water)

[0124] - COS-OGA 12.5 (treatment with half dose of 12.5 mg.L' 1 of COS-OGA)

[0125] - Goal (treatment with 1 mM sodium butyrate alone on day JO)

[0126] - Pretreatment. But / COS-OGA (pretreatment for 48 h with 1 mM sodium butyrate then with a half dose of 12.5 mg.L 1 of COS-OGA)

[0127] - ABE-IT 56 (treatment with a dose of 3.25 gL' 1 of ABE-IT 56, active ingredient of Belvine)

[0128] - Pretreatment. But / ABE-IT 56 (pretreatment for 48 h with 1 mM sodium butyrate then with a dose of 3.25 gL' 1 of ABE-IT 56)

[0129] Figure 7: Figure 7 represents a bar diagram showing the accumulation of the mRNA of the STS gene encoding stilbene synthase in grapevine cells in their culture medium without treatment (vertical gray and white hatching induced by 1 mM sodium butyrate (the medium comprising 1 mM sodium butyrate), (medium gray fill 6.25 mg.L 1 of COS-OGA (gray and white diagonal hatching) (the medium comprising 6.25 mg.L -1 of COS-OGA), cotreatment with 1 mM butyrate and 6.25 mg.L 1 of COS-OGA (grey filling with white dots) (the medium comprising 1 mM sodium butyrate and 6.25 mg.L 1of COS-OGA), as a function of time in hours. Figure 8: Figure 8 represents a bar graph showing the accumulation of the mRNA of the PAL gene encoding Phenylalanine Ammonia Lyase in grapevine cells in a culture medium without treatment (vertical gray and white hatching induced by 1 mM sodium butyrate (medium gray fill (the medium including 1 mM sodium butyrate), 6.25 mg.L 1 of COS-OGA (gray and white diagonal hatching) (the medium comprising 6.25 mg.L 1 of COS-OGA), cotreatment with 1 mM butyrate and 6.25 mg.L 1 of COS-OGA (grey filling with white dots) (the medium comprising 1 mM sodium butyrate and 6.25 mg.L 1 of COS-OGA), as a function of time in hours.

[0130] Figure 9: Figure 9 represents a bar graph showing the accumulation of mRNA of the PR-3 gene encoding a chitinase in grapevine cells in a culture medium without treatment (vertical gray and white hatching induced by 1 mM sodium butyrate (the medium comprising 1 mM sodium butyrate), 6.25 mg.L 1 of COS-OGA (gray and white diagonal hatching (the medium comprising 6.25 mg.L 1 of COS-OGA), cotreatment with 1 mM butyrate and 6.25 mg.L 1 of COS-OGA (grey fill with white dots IB) (the medium comprising 1 mM sodium butyrate and 6.25 mg.L' 1 of COS-OGA), as a function of time in hours.

[0131] Figure 10: Photograph of a Western Blot obtained from vine cell proteins extracted after incubation for 0, 15, 30, 45 or 60 min by compositions comprising respectively: water alone (Control), 1 mM sodium butyrate (But 1 mM), a half-dose of 12.5 mg. 1 of COS-OGA (COS-OGA 12.5), 1 mM sodium butyrate and a half dose of 12.5 mg.L 1 of COS-OGA (But 1 mM + COS-OGA 12.5), 1 mM sodium butyrate 4 h before treatment with a half dose of 12.5 mg. 1 of COS-OGA (But 1 mM (-4h) + COS-OGA 12.5)

[0132] Figure 11: Figure 11 represents a bar chart showing the attack frequency (ordered) by Plasmopara viticola on leaves of Vitis vinifera Chardonnay grapevines, on an experimental plot in Marsannay-la-Côte (21) without treatment: TNT, untreated control, after treatment with Belvine with a concentration of 3.25 gL' 1of ABE-IT 56 (Belvine PD, black and white vertical hatching llll), Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56 (Belvine DR; black and white vertical hatching SS, with a composition comprising sodium butyrate at a concentration of 0.22 gL' 1 (ButNa) then 2 hours later Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56

[0133] ((ButNa / Belvine DR) (black and white horizontal hatching =) or sodium butyrate at a concentration of 0.22 gL' 1 (ButNa). The values ​​correspond to the average of the frequencies of three independent plots of five vines.

[0134] Figure 12: Figure 12 represents a bar chart showing the intensity of attack by Plasmopara viticola on leaves of Vitis vinifera Chardonnay grapevines (ordinate), on a plot in Marsannay-la-Côte (21). Without treatment: TNT, untreated control, after treatment with Belvine with a concentration of 3.25 gL' 1 from ABE-IT 56 (Belvine PD, black and white vertical hatching of Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56 (Belvine DR; black and white vertical hatching §§§, with a composition comprising sodium butyrate at a concentration of 0.22 gL' 1 (ButNa) then 2 hours later Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56 ((ButNa / Belvine DR) (black and white horizontal hatching =) or sodium butyrate at a concentration of 0.22 gL' 1(ButNa). The values ​​correspond to the average of the frequencies of three plots of five independent vines. Figure 13: Figure 13 presents a histogram showing the frequency of attack by Plasmopara viticola on bunches of Vitis vinifera Chardonnay grapevines (ordinate), on an experimental plot in Marsannay-la-Côte (21 without treatment: TNT, untreated control, after treatment with Belvine with a concentration of 3.25 gL' 1 from ABE-IT 56 (Belvine PD, black and white vertical hatching Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56 (Belvine DR; black and white vertical hatching §§§, with a composition comprising sodium butyrate at a concentration of 0.22 gL' 1 (ButNa) then 2 hours later Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56

[0135] ((ButNa / Belvine DR) (black and white horizontal hatching =) or sodium butyrate at a concentration of 0.22 gL' 1 (ButNa). The values ​​correspond to the average of the frequencies of three independent plots of five vines.

[0136] Figure 14: Figure 14 shows a histogram representing the intensity of attack by Plasmopara viticola on bunches of Vitis vinifera Chardonnay grapevines, on an experimental plot in Marsannay-la-Côte (21) (ordinate). Without treatment: TNT, untreated control, after treatment with Belvine with a concentration of 3.25 gL' 1 from ABE-IT 56 (Belvine PD, black and white vertical hatching Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56 (Belvine DR; black and white vertical hatching §§§, with a composition comprising sodium butyrate at a concentration of 0.22 gL' 1(ButNa) then 2 hours later Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56 ((ButNa / Belvine DR) (black and white horizontal hatching =) or sodium butyrate at a concentration of 0.22 gL' 1 (ButNa). The values ​​correspond to the average of the frequencies of three independent plots of five vines.

[0137] Example 1: Evaluation of sodium butyrate and / or a plant defense stimulator against infection for the stimulation and / or disinhibition of a plant immune response. Characteristics of the SDPs used on vines:

[0138] COS-OGA (Chitooligosaccharides-Oligogalacturonic acid), the active ingredient in Messenger (marketed by Cérience). It is obtained by combining two SDPs: COS for chitooligosaccharide (from crustacean shells that mimic the cell wall of fungi) and OGA for oligogalacturonides (from citrus pectin that mimic the degradation products of the cell wall of attacked plant cells).

[0139] ABE-IT 56, the active ingredient in Belvine (marketed by the company Cérience), is extracted from the yeast Saccharomyces cerevisiae.

[0140] Plants used:

[0141] - Tobacco (Nicotiana tabacum cv. Xanthi, seeds sold by the company Etsy)

[0142] - Rock cress (Arabidopsis thaliana, seeds marketed by NASC, Eurasian Arabidopsis Stock Centre)

[0143] - Vine (Vitis vinifera cv. Marsellan, plants sold by Velletaz nurseries.

[0144] More generally, all plants expressing type-2 histone deacetylases, i.e. monocotyledons and dicotyledons.

[0145] Microorganisms tested:

[0146] - Plasmopara viticola (oomycete responsible for downy mildew in grapevines)

[0147] - Erysiphe necator (fungus responsible for grape powdery mildew)

[0148] - Hyaloperonospora parasitica N0C02 (fungus or oomycete responsible for downy mildew of Arabidopsis thaliana)

[0149] Preparation of disinhibitory solutions:

[0150] Sodium butyrate and its derivatives, namely hydroxybutyrate, ethylbutyrate and methylbutyrate, correspond to the commercially available products marketed by the company Sigma Aldrich. Sodium butyrate (Ref. 303410, Sigma Aldrich) is a powder to be dissolved in water. A sodium butyrate solution was prepared by dissolving the powder to be dissolved in ultrapure water with an ohmic resistance greater than 18.2 M at room temperature (25°C). The concentration range tested was from 0.11 to 1.1 g per liter (i.e. a concentration of 1 to 10 mM). Alternatively, the solution was prepared by diluting a concentrated solution 100 times. The solubility limit of sodium butyrate is around 100 g per liter.

[0151] Sodium hydroxybutyrate (Ref. 54965, Sigma Aldrich) was prepared according to the method described for butyrate with the same concentrations. In particular, a solution of sodium hydroxybutyrate (Ref. 54965) was prepared by dissolving the powder to be dissolved in ultrapure water with an ohmic resistance greater than 18.2 M at room temperature (25°C). The concentration range tested was from 0.126 to 1.26 g per liter (i.e., a concentration of 1 to 10 mM). Alternatively, the solution was prepared by diluting a concentrated solution 100 times. The solubility limit of butyrate is around 100 g per liter.

[0152] Ethyl (Ref. E 15701) and methyl (Ref. 277452) butyrate are marketed by Sigma Aldrich in liquid form at concentrations varying depending on the manufacturer. Solutions with a concentration ranging from 0.116 to 1.16 g per liter and 0.102 to 1.02 g per liter, respectively (i.e., a concentration of 1 to 10 mM) were prepared by dilution in ultrapure water with an ohmic resistance greater than 18.2 M at room temperature (25°C). These two compounds are also available in powder form to be dissolved in water.

[0153] Ready-to-use solutions stored at room temperature (25°C) should be used within 12 hours of preparation. Concentrated solutions can be stored for several weeks at room temperature (25°C).

[0154] The solutions were prepared using a magnetic stirrer bar with appropriate personal protective equipment (PPE), namely a cotton coat, latex gloves and safety glasses. Butyrate has a strong odor of rancid butter; hydroxy butyrate has no particular odor; butyrate esters, methyl and ethyl, have an odor of apple and pineapple, respectively.

[0155] The two plant defense stimulator (PDS) compounds that were used were COS-OGA (active ingredient of Messenger) and ABE-IT 56 (active ingredient of Belvine) corresponding to the commercially available products marketed by the company Cérience.

[0156] Conditions for growing vine cuttings in controlled conditions (greenhouse):

[0157] All the tests were carried out in a greenhouse on herbaceous cuttings of the Marselan grape variety (Vitis vinifera cv. Marselan; approved clone 980).

[0158] The cuttings were grown on a peat / perlite mixture (70 / 30 m / m). The peat used was Hansatorf peat (pH 4.3) marketed by Floragard and the perlite was Perligran Premium (diameter 1-5 mm) marketed by Knauff.

[0159] First, single-eye herbaceous cuttings were taken from mother plants grown in a greenhouse under the same conditions as the cuttings used in the trials.

[0160] The cuttings were grown for 4 weeks in mini-greenhouses (40x60 cm; closed for two weeks then gradually opened over two weeks) in peat / perlite clods. The Fertiss 2x4cm mini-clods (marketed by the company Fertil) were watered with water for the first 3 weeks, then with the nutrient solution (TOPFERT 2 10-10-10 - marketed by the company Plantin - at 2 ml. 1 of osmosis water with the addition of 1.5 mL. 1of MagPlant “S” - marketed by the company Plantin - of 0.101 mL.L 1 of a mother solution of NaCL - marketed by the company VWR - at 116 gL' 1 and 0.6 mL.L' 1 of a mother solution of CaNOs-4H2O - marketed by the company VWR - at 472 gL' 1 (all in osmosis water) and following a photoperiod of 16 hours day (23-25°C) / 8 hours night (15-19°C).

[0161] After 4 weeks, the cuttings were repotted in a peat-perlite mixture in pots (8x8x8 cm) and grown for 4 weeks with a photoperiod of 16h day (23-25°C) / 8h night (15-19°C)

[0162] Figure 1 illustrates the typical morphology of a cutting of Vitis vinifera Marselan grape variety used in the trials. Only leaves from rows 1 and 2 were used.

[0163] Preparation of inocula

[0164] Plasmopara viticola is the oomycete pathogen of grapevine downy mildew and corresponds to the strain described in Jacquens et al. 2022

[0011] , P. viticola was cultivated by weekly transplanting on Marselan cuttings from infected leaves allowed to sporulate in humid conditions (relative humidity greater than 95%), in the dark for 24 h. The sporangiophores were recovered by washing the underside of the leaves with ultrapure water (Resistivity greater than 18.2 M ). After spontaneous release into water, and quantification of zoospores with the Malassez cell, the inoculation of new plants was done by spraying (Atomizer spray bottle - 20 mL, Dutscher ref. 670884) with a solution of 10 4 zoospores per mL of ultrapure water on the underside.

[0165] Erysiphe necator is the fungal pathogen of grapevine powdery mildew and the strain corresponds to that described by Brulé et al. 2019 [5], E. necator was cultivated by successive subculturing: the ascospores from the cleistothecia of a contaminated leaf, for example for 20 days, were recovered by washing the contaminated leaf in osmosis water. The concentration of ascospores was determined by counting in a Malassez cell and adjusted to a concentration of 10 5 ascospores / mL. Leaves of ranks 1, 2 and 3 (Figure 1) were inoculated by spraying (Atomizer spray bottle - 20 mL, marketed by the company Dutscher under the commercial reference ref. 670884) and the plants were grown in a greenhouse under the following conditions: 25°C during the day / 18°C ​​at night with a photoperiod of 18 h.

[0166] Quantification of contamination and measurement

[0167] Downy mildew: after 5 days of incubation in a greenhouse (photoperiod 16 h day (23-25°C) / 8 h night (15-19°C); no relative humidity control), 6 leaf discs (diameter: 10-12 mm) were made using cork borers (Dutscher Ref 810655) on each inoculated leaf and placed in the light and with a humidity greater than 95%. Photographs of all the discs of the same experiment were taken under identical shooting conditions (focal length, aperture, exposure time). The photographs obtained were then analyzed using Visilog software to determine the percentage of infection of each disc, i.e. to precisely measure the surface of each disc showing white sporulation of P. viticola. A ratio of sporulating surface area to total surface area of ​​the disc was then calculated and thus made it possible to determine the level of infection for each disc.Normalization of the data relative to the untreated control allowed the calculation of the percentage of protection induced by the treatment. The results given correspond to the average obtained from 4 to 6 plants per condition, i.e. at a rate of 12 discs per plant an average of 48 to 72 leaf discs.

[0168] Quantification of the percentage of disc sporulation can also be done using the free ImageJ software. Photographs from the same experiment were taken under identical shooting conditions (lighting, sensitivity, aperture, exposure time) in order to compare the quantifications from one box to another according to the following protocol:

[0169] 1. In ImageJ, open the image file or import an image

[0170] 2. Optionally crop the image:

[0171] 3. Convert the image to 8-bit format 4. Threshold the image. All pixels below the threshold are assigned the value 0 (black), all pixels above the threshold are assigned the value 255 (white). Adjust the value manually by comparing the thresholded image to the original; only the sporulations should be differentiated from the background of the leaf disc.

[0172] 5. Set the measurement parameters:

[0173] • Area

[0174] • Minimum and Maximum gray value (“Min & Max gray value”)

[0175] • mean gray value

[0176] • Area fraction

[0177] 6. If necessary, remove the thresholded areas corresponding to the ribs.

[0178] 7. Select a round Region of Interest (ROI) (area surface data is displayed below the banner) corresponding to the surface of a disc. Exactly overlay the ROI on the disc.

[0179] 8. Quantify the signal: determination of the parameters mentioned / selected in point 5. The Average (“Mean”) and percentage area (“%Area”) values ​​can be used for calculating the protection.

[0180] 9. Move the ROI area to a new disc. Measure in the same way.

[0181] 10. Once the measurements have been taken, transfer the data to a spreadsheet to calculate the percentage of protection induced by the treatments.

[0182] Powdery mildew: after 20 days of incubation (photoperiod 16 h day (23-25°C) / 8 h night (15-19°C); no control of relative humidity), the previously inoculated leaves were collected and classified into 4 categories rated from 0 to 3 according to the intensity of the symptoms observed (0 indicating a total absence of disease, 1 corresponding to a total contaminated surface of 10%, 2 corresponding to a total contaminated surface of 25% and 3 to a total contaminated surface greater than 50%). Experimental protocol

[0183] • Pre-processing approaches (Figure 2 (1 / 2))

[0184] Figure 2 (1 / 2) was obtained by a so-called pretreatment approach. That is, the disinhibitory molecule, namely butyric acid or a butyric acid derivative, or one of their salts was applied by spraying at a concentration between 1 and 10 mM using a spray bottle with an atomizer so as to obtain a droplet density between 20 and 50 droplets per cm 2 , and this X hours before the SDP, X being able to vary from 2 to 48 h. The reference JO corresponds to the infection of the plants by P. viticola or E. necator. The symptoms of the disease were measured at D+6, i.e. 6 days after infection for downy mildew or D+20, i.e. 20 days after infection for powdery mildew.

[0185] • Co-processing approach (Figure 2 (2 / 2))

[0186] Figure 2 (2 / 2) was obtained when the disinhibitory molecule and the SDP were applied simultaneously by spraying using a spray bottle with atomizer, that is to say that the same solution comprising butyric acid or a butyric acid derivative, or one of their salts was applied by spraying at a concentration between 1 and 10 mM on the one hand, and on the other hand one of the two SDPs (Messenger or Belvine) at concentrations of 12.5 mg respectively. 1 and 3.25 g.L' 1 , and this 2 days before the infection of the plants.

[0187] In particular, the first two fully expanded leaves of the apical zone of a herbaceous cutting were treated by spraying (solution droplet density between 20 and 50 droplets per cm 2) on both sides for the mildew protection tests. For the powdery mildew protection tests, the first three unfurled leaves were sprayed with:

[0188] - a solution A comprising butyric acid or a butyric acid derivative, or one of their salts was applied by spraying at a concentration between 1 and 10 mM on the one hand, and on the other hand one of the two SDPs (Messenger or Belvine) at concentrations of 12.5 mg respectively. 1 and 3.25 gL' 1 , and this 2 days before the infection of the plants

[0189] - a solution B comprising the disinhibitory molecule, namely butyric acid or a butyric acid derivative, or one of their salts applied by spraying at a concentration of between 1 and 10 mM using a spray bottle with atomizer so as to obtain a droplet density of between 20 and 50 droplets per cm 2, and this X hours before the SDP, X being able to vary from 2 to 48 h. The reference JO corresponds to the infection of the plants by P. viticola or E. necator in other words at the time of infection. The symptoms of the disease were measured at D+6, namely 6 days or 144h after infection for downy mildew or at D+20, namely 20 days or 480 hours after infection for powdery mildew.

[0190] A 20 mL spray bottle with atomizer from the Dutscher brand (Ref 670884) was used to deposit a homogeneous layer of droplets on each side of the leaf.

[0191] For inoculation with P. viticola, a zoospore solution was sprayed on the lower surface only at a concentration of 10 4zoospores per mL (the zoospores were previously suspended in demineralized water). The plants were immediately placed at room temperature (25°C) in the dark in an atmosphere with a humidity greater than 95% in order to increase the efficiency of the infection. After 3 h in the dark, the plants were placed back in the greenhouse for a period of 5 days. At 5 èmeday, 6 leaf discs of 10 to 12 mm were made per inoculated leaf using a cork borer (Dutscher, ref. 810655) and placed in plastic boxes (Multriroir, BoiteLab Ref 45106BOILAB06) on Whatman paper soaked in water, the upper surface of the leaf in contact with the paper, the lower surface facing upwards. The boxes corresponding to all the modalities were placed simultaneously in an enclosure for 24 h in the light and at 25°C to allow sporulation of P. viticola. The next day the intensity of the symptoms was measured using Visilog as previously described. For infection by E.Necator, both sides of the first three fully spread leaves of the apical zone of a herbaceous cutting were treated by spraying on the upper side using a spray bottle with atomizer (20 mL) of the Dutscher brand (Ref 670884), so as to deposit a homogeneous layer of droplets on each side of the leaf. After 3 hours of drying (time allowing drying of the solution droplets on the surface of the leaves) on the bench, the plants were transferred to the greenhouse for a period of 20 days. On 20. ème day, the blade of the three inoculated leaves was removed and the intensity of the symptoms was assessed visually as described previously.

[0192] Results :

[0193] 1. Effect of sodium butyrate and / or a plant defense stimulator against infection

[0194] The SDP was the COS-OGA marketed by the company Cérience under the commercial reference Messager.

[0195] Figure 3 represents a histogram including the results obtained and showing the effectiveness of the protection induced against P. viticola (in %), the agent of vine downy mildew, according to the treatments carried out. 6 different treatments were carried out:

[0196] - Control (treatment with water)

[0197] - Goal (treatment with 1 mM sodium butyrate alone on day JO)

[0198] - COS-OGA 12.5 (treatment with half a dose of COS-OGA at 12.5 mg.L- 1 The approved dose for field treatments is 25 mg. 1 )

[0199] - Pretreatment. But / COS-OGA (pretreatment for 48 h with 1 mM sodium butyrate then treatment with half dose of COS-OGA 12.5 mg.L 1 )

[0200] - Co-treatment. But / COS-OGA (simultaneous treatment with 1 mM sodium butyrate and half dose of COS-OGA 12.5 mg.L- 1. Both molecules are dissolved in the same solution) - COS-OGA 25 (treatment with a full dose of COS-OGA at 25 mg.L 1 )

[0201] The process applied for each of the treatments is as described above.

[0202] In Figure 3, the values ​​presented correspond to the average of three independent experiments and are expressed as a percentage of induced protection, with 100% induced protection corresponding to a total absence of P. viticola development.

[0203] The results obtained in Figure 3 clearly demonstrate that disinhibition of the plant's immune responses alone is not sufficient to induce significant protection against P. viticola, nor is a half dose of COS-OGA (12.5 mg.L 1 ).

[0204] As shown in Figure 3, surprisingly and unexpectedly, when sodium butyrate is combined with half a dose of COS-OGA i.e. a concentration of 12.5 mg. 1 the protection induced is at least similar to that obtained with a full dose of COS-OGA (25 mg.L 1 ) in the case of co-treatment, or even a significant increase when sodium butyrate is applied 48 h before the full dose of COS-OGA.

[0205] In other words, the results obtained clearly demonstrate that the combination of sodium butyrate and an SDP compound advantageously and surprisingly allows significant protection of a plant against a pathogen while reducing by half the quantity / concentration of the plant defense-stimulating compound.

[0206] The same tests were carried out to determine the induction of protection against E. Necator, an oomtcete responsible for powdery mildew in grapevines (tests carried out on herbaceous cuttings of Vitis vinifera Marselan grape variety).

[0207] The results obtained are shown in Figure 4. Figure 4 represents a histogram showing the effectiveness of the protection induced against E. Necator (in %), the agent of grapevine powdery mildew, as a function of the treatments carried out. 6 different treatments were tested according to the method described above (from left to right):

[0208] - Ctle (Control, treatment with water)

[0209] - COS-OGA 12.5 (treatment with half a dose of COS-OGA at 12.5 mg.L- 1 The approved dose for field treatments is 25 mg. 1 )

[0210] - Goal (treatment with 1 mM alone on day JO)

[0211] - Pretreatment. But / COS-OGA (pretreatment for 48 h with 1 mM sodium butyrate then treatment with a dose of COS-OGA 12.5 mg.L 1 )

[0212] - ABE-IT 56 (treatment with 3.25 gL' 1 of ABET-IT 56, active ingredient of Belvine)

[0213] - Pretreatment. But / ABE-IT 56 (pretreatment for 48 h with 1 mM sodium butyrate then with a dose of 3.25 gL' 1 of ABET-IT 56, active ingredient of Belvine)

[0214] The results obtained in Figure 4 clearly demonstrate that sodium butyrate alone used at a dose of 1 mM induces significant protection against E. necator, similar to that induced by ABE-IT 56 (active ingredient of Belvine), whereas COS-OGA (active ingredient of Messenger) does not induce significant protection when used at half dose. Pretreatment for 48 h with sodium butyrate prior to the application of a dose of COS-OGA of 12.5 mg. 1or a dose of ABE-IT 56 of 3.25 gL -1 significantly increases the protection induced by the two SDPs used alone.

[0215] As shown in Figure 4, surprisingly and unexpectedly, when sodium butyrate is combined with half a dose of COS-OGA i.e. a concentration of 12.5 mg. 1 or at a dose of 3.25 gL' 1 of ABE-IT 56, the protection induced is greater than that induced by the two SDPs applied alone.

[0216] In this pathosystem, the general conclusion is the same as that established above for protection against P. viticola, except that here sodium butyrate treatment alone is able to induce significant protection against the grapevine powdery mildew agent.

[0217] In other words, the results obtained clearly demonstrate that the combination of sodium butyrate and an SDP compound advantageously and surprisingly allows significant protection of a plant against a pathogen and advantageously allows the quantity / concentration of the plant defense-stimulating compound to be reduced by half.

[0218] 2. Effect of sodium butyrate, methylbutyrate, sodium ethylbutyrate and / or a plant defense stimulator against infection

[0219] The SDP was the ABE-IT 56 marketed by the company Cérience under the commercial reference Belvine.

[0220] Figure 5 shows the results obtained with sodium butyrate and sodium butyrate derivatives, namely methyl- and ethyl-butyrate. Figure 5 shows a histogram showing the protection induced against E. necator, the agent of grapevine powdery mildew, following treatment of the plant with ABE-IT 56 (active ingredient of Belvine) and treatment with sodium butyrate and methyl-butyrate and / or ethyl-butyrate. These values ​​are representative of two independent experiments.

[0221] The results were obtained with butyrate esters, namely methyl butyrate and ethyl butyrate. 6 treatments were applied (from left to right):

[0222] - Control (treatment with water)

[0223] - Goal (treatment with 1 mM sodium butyrate alone on day JO)

[0224] - ABE-IT 56 (treatment with a dose of 3.25 gL -1 of ABE-IT 56, active ingredient of Belvine)

[0225] - Pretreatment. But / ABE-IT 56 (pretreatment for 48 h with 1 mM sodium butyrate then with a dose of 3.25 gL' 1 of ABE-IT 56) - Pretreatment. MeBut I ABE-IT 56 (pretreatment for 48 h with 1 mM methyl-butyrate then with a dose of 3.25 gL' 1 of ABE-IT 56)

[0226] - Pretreatment. EtBut / ABE-IT 56 (pretreatment for 48 h with 1 mM ethyl-butyrate then with a dose of 3.25 gL -1 of ABE-IT 56)

[0227] The values ​​presented correspond to the average of two independent experiments and were expressed as a percentage of induced protection, with 100% induced protection corresponding to a total absence of development of E. necator, the agent of grapevine powdery mildew.

[0228] The results obtained in Figure 5 clearly demonstrate that the combination of sodium butyrate and butyrate derivatives, namely methyl- and ethyl-butyrate with an SDP compound, namely ABE-IT 56, surprisingly and unexpectedly allows a significant increase in the protective efficacy induced by ABE-IT 56 used alone. Furthermore, the results obtained in Figure 5 clearly demonstrate that the combination of sodium butyrate and butyrate derivatives, namely methyl- and ethyl-butyrate with an SDP compound, namely ABE-IT 56, surprisingly and unexpectedly allows a synergistic effect regarding the protective efficacy.

[0229] The results indicate that pretreatment with sodium butyrate or with either of these two esters (methyl- and ethyl-buryrate) significantly increases the protection induced by ABE-IT 56.

[0230] 3. Effect of sodium butyrate and / or a plant defense stimulator on infection of Arabidopsis thaliana by Hyaloperonospora aradibopsidis NOCO2

[0231] The study of the disinhibition of the plant immune response by sodium butyrate and / or a plant defense stimulatory compound was carried out on the model plant Arabidopsis thaliana ecotype ColO (no agronomic application on this plant) following an infection by Hyaloperonospora aradibopsidis NOCO2 (agent of downy mildew). The strain used corresponds to the strain described in Manzoor et al. 2013

[0012] , Seeds of Arabidopsis thaliana ecotype Columbia (Col 0) were sown on peat pellets (100 seeds per pellet) (Jiffy- 7 33 mm pellet-pack, marketed by the company Jiffy Products International AS) and placed in a growth chamber (10 h day at 20°C and 14 h night at 18°C). After 12 days of culture, 500 pL of a solution of H. arabidospidis NOCO2 spores (at a concentration of 5.10 4spores / mL) were sprayed on the plants using a spray bottle with a 20 mL atomizer. The inoculated plants were placed in an airtight mini-greenhouse (supplier: Naturegardening), humidity greater than 95%, 10 h day at 20°C and 14 h night at 18°C ​​for 7 days. The aerial parts of three plants grown on three peat pellets having received the same treatment and being inoculated in the same way were cut, grouped and weighed. The oospores present on the leaves were recovered by washing in a volume of 10 mL of ultrapure water (resistivity greater than 18 mΩ). The quantity of oospores recovered was determined by counting in a Malassez cell and the values ​​were normalized per gram of fresh leaf material.

[0232] The results obtained were shown in Figure 6. Figure 6 represents a histogram showing the protection induced against H. aradibopsidis NOCO2, the agent of downy mildew in Arabidopsis thaliana following treatment of the plant with ABE-IT 56 (active ingredient of Belvine) or with COS-OGA (active ingredient of Messenger) and treatment with sodium butyrate. These values ​​are representative of two independent experiments. The treatment methods were (from left to right):

[0233] - Ctle (treatment with water)

[0234] - COS-OGA 12.5 (treatment with half dose of 12.5 mg.L' 1 of COS-OGA)

[0235] - Goal (treatment with 1 mM sodium butyrate alone on day D-2)

[0236] - Pretreatment. But / COS-OGA (pretreatment for 48 h with 1 mM sodium butyrate then with a half dose of 12.5 mg.L -1 of COS- OGA) - ABE-IT 56 (treatment with a dose of 3.25 gL' 1of ABE-IT 56, active ingredient of Belvine)

[0237] - Pretreatment. But / ABE-IT 56 (pretreatment for 48 h with 1 mM sodium butyrate then with a dose of 3.25 gL -1 of ABE-IT 56) The values ​​presented correspond to the average of two independent experiments and were expressed as a percentage of induced protection, 100% of induced protection corresponding to a total absence of development of H. arabidopsidos NOCO2.

[0238] The results obtained in Figure 6 clearly demonstrate that sodium butyrate advantageously induces a protective efficacy identical to that induced by COS-OGA. The results obtained also clearly, surprisingly and unexpectedly demonstrate that the combination of sodium butyrate and COS-OGA has a synergistic effect on plant protection. The results obtained also clearly, surprisingly and unexpectedly demonstrate that the combination of sodium butyrate and ABE-IT 56 has a synergistic effect on plant protection.

[0239] The results obtained therefore clearly demonstrate that butyric acid or a butyric acid derivative, or one of their salts, advantageously provides protection for plants against infections.

[0240] The results obtained therefore clearly demonstrate that the combination of butyric acid or a butyric acid derivative, or one of their salts and a plant defense stimulator compound advantageously allows the obtaining of a synergistic effect for the protection of plants against infections.

[0241] The results obtained further clearly demonstrate that butyric acid or a butyric acid derivative, or one of their salts, advantageously allows stimulation and / or disinhibition of plant immune responses.

[0242] The results obtained therefore clearly demonstrate that the combination of butyric acid or a butyric acid derivative, or one of their salts and a plant defense stimulatory compound advantageously allows synergistic stimulation and / or disinhibition of plant immune responses.

[0243] 4. In vitro study of cell culture treatment with butyrate and / or a plant defense stimulator

[0244] Grapevine cell cultures (Y. vinifera Marselan variety) were used to determine whether, at the level of cell signaling leading to the development of the immune response, the synergistic effect following treatment with sodium butyrate and / or an SDP, COS-OGA in this case, led to more intense and / or earlier defense responses.

[0245] Two cellular responses associated with the establishment of immune responses were studied: the activation of certain defense genes, namely the genes STS (for Stilbene synthase, NCBI Reference: XM_003634017.4), PAL (for Phenylalanine amonia lyase, NCBI Reference: XM_002281763.5) and PR-3 (for Pathogenesis-related 3, NCBI Reference: NM_001281244.1) and the activation of a family of specific proteins, MAPK (for Mitogen-Activated Protein Kinase). The vine cells (Vitis vinifera Marsellan grape variety) were treated in their culture medium (Nitsch-Nitsch medium - marketed by the company Duchefa under the reference Ref. N0224.0025) supplemented with 58 mM of sucrose - marketed by the company SigmaAldrich under the reference Ref. S0389), under agitation (125 rotations per minute) and at 25°C. To study the activation of defense genes, mRNA from grapevine cells was extracted using the following protocol.After being ground in liquid nitrogen (-196°C) using a mortar / pestle, the samples were treated with TrizolTM (Gibco BRL) at a rate of 1 mL per 100 mg of ground tissue in a 1.5 mL Eppendorf tube (Dutcher, Ref. 133511). After adding 200 μL of chloroform (Supelco, Ref. 102445), the tubes were shaken vigorously and left at room temperature (25°C) for 10 minutes. The samples were then centrifuged at 12,000xg at 4°C for 15 min using a benchtop centrifuge (Eppendorf). The aqueous phase was collected by pipette and transferred to a new 1.5 mL Eppendorf tube; Total RNA was then precipitated by adding 500 μL of isopropanol (Supelco Ref. 109634) and left to incubate for 10 min at room temperature (25°C). After centrifugation at 12,000xg at 4°C for 10 min and removal of the supernatant by pipette, the RNA pellets were washed with 1 mL of ethanol (Sigma-Aldrich Ref. 8.18760) 70% (v / v in diethyl pyrocarbonate-treated water - DEPC -; Sigma-Aldrich Ref. 3660). After a final centrifugation at 12,000xg at 4°C for 5 min and removal of the supernatant by pipette, the total RNA pellets were finally taken up in 30 pL of DEPC-treated water. The concentration and purity of total RNA were assessed by spectrophotometry at 260 nm (Nanodrop).

[0246] The mRNAs were reverse transcribed using a 15-thymine primer (oligo-dT, Eurofins) that hybridizes to the polyA end of the mRNAs. For this, 1 pg of total RNA was diluted in 4 pL of DEPC-treated water and the reaction mixture contained (according to the supplier's recommendations, Superscript IV from Thermofischer Scientific) 1X concentrated reaction buffer containing the dNTPs required for reverse transcription, 10 mM MgCh, 100 ng of oligo-dT and 2 pL of a reaction mixture containing Superscript IV reverse transcriptase and RNAse inhibitors). All solutions were provided in the Superscript IV kit from Thermofischer Scientific. The samples thus prepared were incubated in a Biorad thermocycler according to the following program: 10 min at 25°C, 1 h at 37°C, 5 min at 85°C. Then, the synthesized cDNAs were stored at -20°C.

[0247] Quantitative PCR was performed using the GoTaq® qPCR Master Mix kit (Promega) with 2 pL of cDNA diluted 1 / 20 in DEPC-treated water and 250 nM of primers specific for the different genes tested (see Table 1 below) and two reference genes (VATP16 - for V-type proton ATPase 16 - and EF1a - for Elongation Factor 1a). PCR reactions were performed in 384-well plates (Nunc, Z723010) under the following conditions: 95°C for 2 minutes; 40 cycles of 3 steps, 95°C for 15 seconds (denaturation), 60°C for 30 seconds (primer annealing), 72°C for 30 seconds with the ViiA™ 7 thermocycler marketed by Applied Biosystems. A final step in the program allowed the specificity of the amplicons to be verified by an analysis of the melting curves. The quantification of the transcripts was determined by the comparative 2' method AACt (Pfaffl, 2001)

[0013] .

[0248] The specific primers for the genes studied were as follows:

[0249] Table 1:

[0250] In particular, a study of the possible activation of defense genes was carried out. These were the following three: the STS gene (for Stilbene Synthase; Figure 7), the PAL gene (for Phenylalanine Ammonia Lyase: Figure 8) and the PR-3 gene (for Pathogenesis Related-3; Figure 9). These two genes encode proteins involved in the synthesis of molecules called phytoalexins, compounds with antimicrobial activity, and in cell wall reinforcement. The results obtained are respectively represented in Figures 7, 8 and 9. In these figures, the values ​​given correspond to the accumulation factor of the mRNA corresponding to these genes measured by quantitative RT-PCR.In particular, Figure 7 represents a bar diagram showing the accumulation of the mRNA of the STS gene encoding stilbene synthase in grapevine cells in their culture medium without treatment (vertical gray and white hatching Ml), following treatment with 1 mM sodium butyrate (medium gray filling). (the medium comprising 1 mM sodium butyrate), at 6.25 mg.L 1 of COS-OGA (gray and white diagonal hatching) (the medium comprising 6.25 mg.L 1 of COS-OGA), to cotreatment with 1 mM butyrate and 6.25 mg.L -1 of COS-OGA (gray filling with white dots (the medium comprising 1 mM sodium butyrate and 6.25 mg.L 1of COS-OGA), as a function of time in hours. Figure 8 represents a bar graph showing the accumulation of the mRNA of the PAL gene encoding Phenylalanine Ammonia Lyase in grapevine cells in a culture medium without treatment (vertical gray and white hatchings IllOi), following treatment with 1 mM sodium butyrate (medium gray filling (the medium comprising 1 mM sodium butyrate), at 6.25 mg.L 1 of COS-OGA (gray and white diagonal hatching) (the medium comprising 6.25 mg.L 1 of COS-OGA), to cotreatment with 1 mM butyrate and 6.25 mg.L 1 of COS-OGA (gray filling with white dots (the medium comprising 1 mM sodium butyrate and 6.25 mg.L 1 of COS-OGA).

[0251] As demonstrated in Figures 7 and 8, the incubation of grapevine cells with butyrate and then COS-OGA surprisingly allows the accumulation of mRNA corresponding to the STS and PAL genes in a synergistic and sustainable manner over time, namely for at least 9 hours. A study of the expression of the PR-3 gene (Figure 9) coding for a chitinase, an enzyme involved in the degradation of the fungal cell wall, was carried out. The results obtained are shown in Figure 9. In this figure, the values ​​given correspond to the accumulation factor of the mRNA corresponding to these genes measured by quantitative RT-PCR. Figure 9 represents a bar graph showing the accumulation of PR-3 gene mRNA in grapevine cells in culture medium without treatment (vertical gray and white hatching B), following treatment with 1 mM sodium butyrate (medium gray filling) (the medium comprising 1 mM sodium butyrate), at 6.25 mg. 1of COS-OGA (gray and white diagonal hatching) (the medium comprising 6.25 mg.L 1 of COS-OGA), to cotreatment with 1 mM butyrate and 6.25 mg.L 1 of COS-OGA (gray filling with white dots B) (the medium comprising 1 mM sodium butyrate and 6.25 mg.L 1 of COS-OGA), as a function of time in hours.

[0252] As shown in Figure 9, the expression of the PR-3 gene is not significantly modified after incubation of grapevine cells with butyrate and then COS-OGA. In particular, the combination appears to have a negative effect on the expression compared to the level expressed after incubation with COS-OGA alone. These results therefore clearly demonstrate that butyric acid or a butyric acid derivative, or one of their salts, optionally combined with at least one plant defense-stimulating compound, advantageously allows the targeted activation of genes involved in immune defenses.

[0253] The results obtained therefore clearly demonstrate that butyric acid or a butyric acid derivative, or one of their salts, advantageously provides protection for plants against infections.

[0254] To study the activation of a family of protein kinases known to be involved in the development of the immune response of plants, MAPKs (for Mitogen-Associated Protein Kinases), total proteins from grapevine cells (Vitis vinifera Marselan grape variety) were extracted after grinding in a mortar / pestle of the cells frozen in liquid nitrogen (-196°C). The proteins were extracted from grapevine cells treated for 0, 15, 30, 45 or 60 min with different treatments, namely compositions comprising in particular:

[0255] - Control (water treatment only)

[0256] - But 1 mM (treatment with 1 mM sodium butyrate)

[0257] - COS-OGA 12.5 (treatment with half dose of 12.5 mg.L' 1 of COS-OGA, active ingredient of the Messenger)

[0258] - But 1 mM + COS-OGA 12.5 (simultaneous treatment with 1 mM sodium butyrate and half dose of 12.5 mg.L 1of COS-OGA, active ingredient of the Messenger) - But 1 mM (-4 h) + COS-OGA 12.5 (treatment with 1 mM sodium butyrate 4 h before treatment with a half dose of 12.5 mg.L' 1 of COS-OGA, active ingredient of the Messenger)

[0259] The treatment consisted of introducing by pipette into 25 mL Erlenmeyer flasks containing 10 mL of vine cells (Vitis vinifera Marselan grape variety) 10 pL of 1000 times concentrated solutions corresponding to the treatments described above.

[0260] Proteins were separated by SDS-PAGE electrophoresis according to the protocol described by Brulé et al. 2019 [5]: 15 min of migration in the 4% acrylamide concentration gel (BioRad) at 80 V followed by 75 min of migration in the 10% acrylamide separation gel (Biorad). After transfer under liquid conditions onto a Nitrocellulose membrane (Amerhsam) for 1 h at 80 V, the MAP kinases were revealed using an antibody directed against phosphorylated and therefore activated MAP kinases (Abeam Ref. ab76299). The intensity of the visible bands reflects the level of activation of two MAP kinases involved in the development of the immune response.

[0261] The results presented in Figure 10 clearly demonstrate that treatment, i.e. incubation of cells with a composition comprising 1 mM sodium butyrate, as well as treatment with a half dose of COS-OGA at 12.5 mg.L -1allows a transient activation of two MAP kinases of molecular masses 45 and 47 kDa with a maximum of activation after 15 min of treatment / incubation. The results therefore clearly and surprisingly demonstrate that the use of butyric acid or a butyric acid derivative, or one of their salts advantageously allows a stimulation and / or disinhibition of a plant immune response.

[0262] The results clearly demonstrate that the treatment, namely the incubation of the cells with 1 mM sodium butyrate, whether or not it precedes by 4 h the incubation of the cells with a half-dose of COS-OGA at 12.5 mg. 1, allows activation of MAP kinases significantly and significantly higher than using the compounds independently. After 15 min of treatment, the activation of 45 and 47 kDa MAP kinases was respectively higher by a factor of 1.70 and 1.53 when grapevine cells were treated with a composition comprising 1 mM sodium butyrate associated with a half-dose of COS-OGA at 12.5 mg. 1 , compared to a solution containing only half a dose of COS-OGA at 12.5 mg.L -1 These activation factors were 1.10 and 1.34, respectively, when the half-dose of COS-OGA of 12.5 mg. 1was applied to grapevine cells 4 h after the application of 1 mM sodium butyrate. In other words, the combination of butyric acid or a butyric acid derivative, or one of their salts and at least one plant defense stimulator (PDS) advantageously and surprisingly allows to obtain a synergistic effect and advantageously to stimulate and / or disinhibit the immune response of plants.

[0263] The results obtained therefore clearly demonstrate that the combination of butyric acid or a butyric acid derivative, or one of their salts and a plant defense stimulator compound advantageously allows the obtaining of a synergistic effect for the protection of plants against infections.

[0264] The results obtained further clearly demonstrate that butyric acid or a butyric acid derivative, or one of their salts, advantageously allows stimulation and / or disinhibition of plant immune responses.

[0265] The results obtained therefore clearly demonstrate that the combination of butyric acid or a butyric acid derivative, or one of their salts and a plant defense stimulatory compound advantageously allows synergistic stimulation and / or disinhibition of plant immune responses.

[0266] Example 2: Evaluation of sodium butyrate and / or a plant defense stimulator against infection In this example, the Plant Defense Stimulator (PDS) was ABE-IT 56 marketed by Cérience under the trade name Belvine. Sodium butyrate was the commercially available product marketed by Sigma Aldrich under the reference Ref. 303410, Sigma Aldrich.

[0267] The preparation of the sodium butyrate solution was carried out according to the method described in Example 1 above.

[0268] In this example the concentration of sodium butyrate in the solution is 0.22 gL -1 or a concentration of 2 mM.

[0269] In this example, the trials were carried out in open fields on a plot of Vitis vinifera, a Chardonnay grape variety from the University of Burgundy estate in Marsannay-la-Côte, at the place called “Les plattières”.

[0270] The plot comprised 3 independent blocks which were divided into 5 plots each comprising 5 plants / vines.

[0271] In other words, in a homogeneous area of ​​the plot, 3 independent blocks each containing 5 plots of 5 plants / vines were defined. The following five treatments were applied randomly to these 3 blocks:

[0272] • TNT: untreated control

[0273] • Belvine PD: Belvine full dose (3.25 g of ABE-IT 56 per liter)

[0274] • Belvine DR: Belvine reduced dose (0.75 g of ABE-IT 56 per liter)

[0275] • ButNa: sodium butyrate (0.22 gL -1 )

[0276] • ButNa / Belvine DR: successive application of sodium butyrate (0.22 gL -1 ) then 2 hours later Belvine reduced dose (0.75 g of ABE-IT 56 per liter)

[0277] The above-mentioned compositions for application on the plot, also mentioned for treatment, were prepared extemporaneously by dissolving sodium butyrate or diluting Belvine in demineralized water.

[0278] A preventive anti-powdery mildew treatment was carried out throughout the growing season by spraying sulfur on all the blocks uniformly. These anti-powdery mildew treatments were not carried out at the same time as the treatments using a composition according to the invention and were not carried out at the same frequency.

[0279] Treatments were applied every 7 days on average, unless there was a rain event on the day of treatment. In this case, the treatment was brought forward or delayed by one day. Treatments were carried out manually using a Berthoud brand backpack sprayer, commercially known as Cosmos 18. The sprayed volume ranged from 100 to 300 L.ha. -1, depending on the foliage development. The density of the plot being 10,000 vines per hectare, the sprayed volume per vine was 10 to 30 mL. Both sides of the row and both sides of the leaves were treated by rocking movements of the nozzle located approximately 30 cm from the foliage. The spray pressure was between 1 and 2 bars. The spraying was carried out in order to obtain a droplet density on the leaf of between 30 and 100 droplets per cm 2 of leaf.

[0280] Quantification of contamination and measurement

[0281] The symptoms of downy mildew (Plasmopara viticola) development were determined by measuring two parameters: attack frequency and disease intensity, on leaves and on bunches. These two indices were determined according to the protocol below.

[0282] To determine the attack frequency on leaves: twenty leaves located in the central part of the branches of each of the five plants / vines of each plot, i.e. one hundred leaves per plot, corresponding respectively to each of the treatments were observed. The presence of at least one area called "oil spot" corresponding to the characteristic symptom linked to the development of P. viticola on a leaf indicated and categorized the leaf as contaminated. The attack frequency corresponds to the percentage of contaminated leaves, i.e. the ratio between the number of contaminated leaves and the total number of leaves observed per plot. To determine the intensity on leaves: twenty leaves of each of the five vines of each plot, i.e. one hundred leaves per plot, corresponding to a treatment and located in the central part of the branches were observed.According to the OIV 452-1 reference grid of the International Organisation of Vine and Wine (OIV), a percentage of contaminated leaf surface was estimated according to this same reference grid by visual estimation.

[0283] To determine the frequency of attack on bunches: five bunches of each of the five vines in each plot, i.e. 25 bunches per plot, corresponding to one treatment were observed. The presence of at least one area of ​​attack by P. viticola corresponding to the appearance of a symptom called "oil spot" indicated and categorized the bunch as a contaminated bunch. The attack frequency corresponds to the percentage of contaminated bunches, i.e. the ratio between the number of contaminated bunches and the total number of bunches observed per plot.

[0284] To determine the intensity on the bunch: five bunches of each of the five vines of each plot, i.e. 25 bunches per plot, corresponding to one treatment were observed. According to the OIV 453 reference grid of the International Organisation of Vine and Wine (OIV), a percentage of volume of each contaminated bunch was visually estimated according to the OIV 453 grid mentioned above.

[0285] The results obtained concerning the frequency of attack by Plasmopara viticola on leaves of Vitis vinifera Chardonnay grapevines, on an experimental plot in Marsannay-la-Côte (21). are shown in Figure 11. Figure 11 corresponds to a histogram representing the frequency of attack as a function of the treatments carried out. In particular, 5 treatments were carried out according to the method described above:

[0286] - TNT, untreated control;

[0287] - Belvine PD, Belvine at a concentration of 3.25 gL'1 of ABE-IT 56;

[0288] - Belvine DR, Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56; - ButNa I Belvine DR, successive application of sodium butyrate at a concentration of 0.22 gL' 1 then 2 hours later Belvine at a concentration of 0.75 gL' 1 of ABE-IT 56;

[0289] - ButNa, sodium butyrate at a concentration of 0.22 gL' 1 .

[0290] The results presented in Figure 11 correspond to the average values ​​of the frequencies of three plots of five independent vines and are expressed as a percentage of contaminated leaves. The leaf attack frequencies were determined according to the method described above.

[0291] Figure 12 represents a histogram including the results obtained and showing the intensity of attack by Plasmopara viticola on leaves of Vitis vinifera Chardonnay grapevines, on an experimental plot in Marsannay-la-Côte (21). The 5 previous treatments were applied and the method of applying the treatments is as described above.

[0292] The results presented in Figure 12 correspond to the average values ​​of the intensities of three plots of five independent vines and are expressed as a percentage of contaminated leaf surface. The symptoms were quantified on June 18, 2024. The assessment of the attack intensity on the leaf is as described above.

[0293] As shown in Figures 11 and 12, the combination of sodium butyrate and a plant defense stimulator (PDS) compound advantageously makes it possible to significantly reduce the attack frequency and the attack intensity by Plasmopara viticola compared to the use of each of the compounds taken in isolation. In particular, the results clearly demonstrate that a combination of sodium butyrate and a plant defense stimulator (PDS) compound makes it possible to significantly reduce the attack frequency and the attack intensity by Plasmopara viticola and, surprisingly, to reduce the concentration of the PDS compound by more than 4 times.Furthermore, surprisingly, the results clearly demonstrate that the application of sodium butyrate and a plant defense stimulator (PDS) compound, for example ABE-IT 56, at a concentration 4 times lower than that commonly used, significantly reduces the attack frequency on leaves compared to the frequency obtained with the application of ABE-IT 56 alone at the same concentration. Furthermore, the results clearly demonstrate that the application of sodium butyrate and a plant defense stimulator (PDS) compound, for example ABE-IT 56, at a concentration 4 times lower than that commonly used, significantly reduces the attack intensity compared to the frequency obtained with the application of ABE-IT 56 alone at the same concentration.In addition, the combination of sodium butyrate and a plant defense stimulator (PDS) compound surprisingly synergistically reduces the intensity of leaf attack.

[0294] The results obtained concerning the frequency of attack by Plasmopara viticola on bunches of Vitis vinifera Chardonnay grapevines, on an experimental plot in Marsannay-la-Côte (21) are shown in Figure 13. Figure 13 represents a histogram representing the frequency of attack as a function of the treatments carried out. In particular, 5 treatments were carried out according to the method described above.

[0295] - TNT, untreated control;

[0296] - Belvine PD, Belvine at a concentration of 3.25 gL' 1 of ABE-IT 56;

[0297] - Belvine DR, Belvine at a concentration of 0.75 gL -1 of ABE-IT 56;

[0298] - ButNa / Belvine DR, successive application of sodium butyrate at a concentration of 0.22 gL -1 then 2 hours later Belvine at a concentration of 0.75 gL -1 of ABE-IT 56;

[0299] - ButNa, sodium butyrate at a concentration of 0.22 gL' 1 .

[0300] The results presented in Figure 13 correspond to the average values ​​of the frequencies of three plots of five independent vines and are expressed as a percentage of contaminated bunches. The frequencies of attacks on bunches were determined according to the method described above.

[0301] Figure 14 represents a histogram including the results obtained and showing the intensity of attack by Plasmopara viticola on bunches of Vitis vinifera Chardonnay grapevines, on an experimental plot in Marsannay-la-Côte (21). The 5 previous treatments were applied and the method of applying the treatments is as described above.

[0302] The results presented in Figure 14 correspond to the average values ​​of the intensities of three plots of five independent vines and are expressed as a percentage of the volume of each contaminated bunch. The evaluation of the attack intensity on the bunch was carried out according to the method described above.

[0303] As shown in Figures 13 and 14, the combination of sodium butyrate and a plant defense stimulator (PDS) compound advantageously and significantly reduces the attack frequency and attack intensity on grape clusters by Plasmopara viticola compared to the use of each of the compounds taken separately. In particular, the results clearly demonstrate that a combination of sodium butyrate and a plant defense stimulator (PDS) compound significantly reduces the attack frequency and attack intensity by Plasmopara viticola and, surprisingly, reduces the concentration of the PDS compound by more than 4 times.Furthermore, surprisingly, the results clearly demonstrate that the application of sodium butyrate and a plant defense stimulator (PDS) compound, for example ABE-IT 56, at a concentration 4 times lower than that commonly used, significantly reduces the attack frequency on bunches compared to the frequency obtained with the application of ABE-IT 56 alone at the same concentration. Furthermore, the results clearly demonstrate that the application of sodium butyrate and a plant defense stimulator (PDS) compound, for example ABE-IT 56, at a concentration 4 times lower than that commonly used, significantly reduces the attack intensity compared to the frequency obtained with the application of ABE-IT 56 alone at the same concentration.Furthermore, the combination of sodium butyrate and a plant defense stimulator (PDS) compound surprisingly allows synergistically reducing the intensity and frequency of cluster attack. The results obtained therefore clearly demonstrate that the combination of butyric acid or a butyric acid derivative, or one of their salts and a plant defense stimulator compound advantageously allows obtaining a synergistic effect for the protection of plants against infections.

[0304] The results obtained therefore clearly demonstrate that the combination of butyric acid or a butyric acid derivative, or one of their salts and a plant defense stimulatory compound advantageously allows synergistic stimulation and / or disinhibition of plant immune responses.

[0305] References

[0306] 1. Jones and Dangl, 2006 The plant immune system. Nature, 444; 323-329.

[0307] 2. Garcia-Brugger et al. 2006 Early signaling events induced by elicitors of plant defenses. Mol. Plant-Microbe Inter. 19; 711-724

[0308] 3. Héloir et al. 2019, Grapevine recognition of elicitors: from the MAMP / DAMP perception to induced resistance. Front. Plant Sci. 10; 1117

[0309] 4. Krzyzaniak et al. 2018, A Plant Extract Acts Both as a Resistance Inducer and an Oomycide Against Grapevine Downy Mildew. Front Plant Sci. 9;1085.

[0310] 5. Brulé D. et al. 2019. The grapevine (Vitis vinifera) LysM receptor kinases VvLYK1-1 and VvLYK1-2 mediate chitooligosaccharide- triggered immunity. Plant Biotechnol. J. 17; 812-825

[0311] 6. Grandperret et al. 2013. Type-ll Histone DeACetylases: elusive plant nuclear signal transducers. Plant Cell Environ., 37; 1259-1269.

[0312] 7. Nicolas-Francès et al. 2018, Evolutionary diversification of type-2 HDAC structure, function and regulation in Nicotiana tabacum. Plant Sci., 269; 66-74.

[0313] 8. Bourque S. et al. 2011. Type-2 histones deacetylases as new regulators of elicitor-induced cell death in plants. New Phytol. 192; 127-139.

[0314] 9. Bourque S. et al. 2016. The evolution of HD2 proteins in green plants. Trends Plant Sci. 21 ; 1008-1016.-2016

[0315] 10.Schneider et al. 2019. INRA-ResDur: the French grapevine breeding programme for durable resistance to downy and powdery mildew. Acta Hortic. 1248. ISHS 2019, 2017-213.

[0316] H.Jacquens L et al. 2022.. Biostimulation can prime elicitor induced resistance of grapevine leaves to downy mildew. Front Plant Sci. 2022 Nov 9; 13:998273 Manzoor H et al. 2013. Involvement of the glutamate receptor AtGLR3.3 in plant defense signaling and resistance to Hyaloperonospora arabidopsidis. Plant J, 76: 466-480. Pfaffl. 2001. A new mathematical model for relative quantification in real-time RT-PCR. Nucleic Accids Res. 29, 2002-2007.

Claims

Claims 1. Use of butyric acid or a butyric acid ester or a hydroxybutyric acid, or one of their salts and at least one plant defense stimulator (PDS) for the stimulation and / or disinhibition of a plant immune response.

2. Use according to the invention of claim 1 in which the butyric acid ester is chosen from methyl and ethyl ester, and a hydroxybutyric acid, or one of their salts.

3. Use according to claim 1 or 2 in which the salt is chosen from sodium, calcium or potassium salt, preferably sodium.

4. Use of any one of claims 1 to 3 wherein the butyric acid salt is sodium butyrate.

5. Use according to any one of claims 1 to 4 wherein said at least one plant defense stimulator (PDS) is chosen from the group comprising COS-OGA (chitooligosaccharide-oligogalacturonide), ABE-IT 56.

6. Use according to any one of claims 1 to 5 in which butyric acid or butyric acid ester or hydroxybutyric acid, or one of their salts, and said at least one plant defense stimulator (PDS) are included in a phytosanitary composition.

7. Use according to any one of claims 1 to 6, in which the concentration of butyric acid or butyric acid ester or hydroxybutyric acid, or one of their salts, is from 1 to 10 mM.

8. Use according to claim 6 or 7, wherein the concentration of said at least one plant defense stimulator (PDS) is from 0.05 to 4 gL' 1 9. Phytosanitary composition comprising butyric acid or a butyric acid ester or a hydroxybutyric acid, or one of their salts and at least one plant defense stimulator (PDS).

10. Composition according to claim 9 in which the concentration of butyric acid or butyric acid ester or hydroxybutyric acid, or one of their salts is from 1 to 10 mM.

11. Composition according to claim 9 or 10, wherein said at least one plant defense stimulator (PDS) is selected from the group comprising COS-OGA (chitooligosaccharide-oligogalacturonide), ABE-IT 56.

12. Composition according to any one of claims 9 to 11 in which the concentration of said at least one plant defense stimulator (PDS) is between 0.05 and 4 gL' 1 13. A method of treating a plant infection comprising the steps of: a) administering butyric acid or a butyric acid ester or a hydroxybutyric acid, or one of their salts or a phytosanitary composition comprising butyric acid or a butyric acid ester or a hydroxybutyric acid, or one of their salts, b) administering at least one plant defense stimulator (PDS) or a composition comprising at least one plant defense stimulator (PDS), wherein the administration of butyric acid or butyric acid ester or hydroxybutyric acid, or one of their salts or a phytosanitary composition comprising a butyric acid or a butyric acid ester or a hydroxybutyric acid, or one of their salts is prior, simultaneous or concomitant with the administration of at least one plant defense stimulator (PDS) or a composition comprising at least one plant defense stimulator (PDS).

14. Phytosanitary kit intended to be used for the stimulation and / or disinhibition of the immune response of plants and / or the treatment of a plant infection comprising: i. a butyric acid or a butyric acid ester or a hydroxybutyric acid, or one of their salts, and ii. at least one plant defense stimulator (PDS).

15. A kit for use according to claim 14 wherein - butyric acid or a butyric acid derivative, or one of their salts, can be used by spraying a phytosanitary composition comprising from 1 to 10 mM of said butyric acid or butyric acid derivative, or one of their salts, and - said plant defense stimulator (PDS) can be used by spraying a composition comprising said plant defense stimulator (PDS) within 5 minutes to 24 hours after the first spraying of said butyric acid or butyric acid derivative, or one of their salts. CORRECTED SHEET (RULE 91) ISA / EP

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