Isoflavone derivatives for agricultural use to promote plant growth, yield, flowering, fruit set, and / or protect plants against abiotic and biotic stresses

Abstract

The present invention relates to the use of certain isoflavone derivatives or an agriculturally acceptable salt thereof, to increase growth,yield, flowering and / or furuit set of a plant, at any developmental stage, as compared to the non-treated plant of the same species and at the same developmental stage, and to its use to further increase the adaptability of the plant to an abiotic and / or biotic stress. It also relates to certain isoflavone derivative compounds and compositions comprising them.

Description

[0001] Isoflavone derivatives for agricultural use to promote plant growth, yield, flowering, fruit set, and / or protect plants against abiotic and biotic stresses.

[0002] Technical Field

[0003] This application claims the benefit of European Patent Application EP25382015.3 filed January 14, 2025.

[0004] The present invention relates to the field of plant biology, breeding and agriculture and refers to compounds, administered separately or in combination, which are useful for promoting growth of plants, flowering and fruit formation. It also relates to the ability of the compounds of the invention to increase plant resistance to stress.

[0005] Background

[0006] As the world’s population continues to grow, food security is becoming a major issue that is further complicated by the potential impact of climate change on crop productivity. Extreme temperatures, drought, and soil salinization are the main adverse environmental conditions affecting crops (see Gupta, A et.al., “The physiology of plant responses to drought”, Science, 2020, vol. 368 (6488), pp.266-269).

[0007] Abiotic stresses, in particular heat and drought, are increasing in freguency and intensity with climate change. In the past decade, all regions across the world had an average annual temperature change of at least 1.0°C, with Europe leading with a 2.1°C annual change. It is expected that global atmospheric temperature will rise by approximately 4°C by 2080. Rising temperatures and drought may hamper food production, affecting both plants and animals alike.

[0008] For immobile plants, abiotic environmental factors are the leading detrimental factors affecting their growth and development. These abiotic stresses result in a range of responses in plants, which may alter biological processes such as gene expression and cell metabolism, among others. Moreover, high temperatures and drought often occur together. Under stress, plants tend to divert energy and resources away from growth and toward a stress response, to ensure survival. Due to this survival strategy, crops under these conditions are not only affected in terms of growth rate but also guality.

[0009] For these reasons, the study of signaling pathways which are activated by plants in response to stress is of great interest. According to Zhang Y. et al., in “Plants’ Response to Abiotic Stress: Mechanisms and Strategies”, Int J Mol Sci. 2023, vol. 24(13), p.10915,in recent years, genome-wide association studies have identified regulators and natural allelic variants of crop responses to abiotic stresses. This has helped to identify genes that may be used to produce more adaptive and higher yielding crops, introducing genetic variations, known as transgenic crops. Biotechnological production of plants tolerant to abiotic stress, in particular drought have been produced previously (see Martignago, D. et al., “Drought Resistance by Engineering Plant Tissue-Specific Responses”, Front Plant Sci., 2020, 10:1676.). Engineering hormone signaling produced plant with improved drought resistance due to reduced ethylene sensitivity and delayed senescence ever to reach the market was Verdeca’s Drought Tolerance Soybeans HB4®(see Bergau, J.,“Verdeca Introduces HB4® Drought Tolerant Soybeans to Growers at Argentina’s Expoagro” [Online], 2019. Another example for improved adaptation to abiotic stress, in particular drought, has been associated with a receptor in WO2015177215A1, where certain genes are modulated to generate a drought tolerant plant without penalizing overall plant growth (see Fabregas, N et al., “Overexpression of the vascular brassinosteroid receptor BRL3 confers drought resistance without penalizing plant growth”, NatCommun, 2018, vol. 9, p. 4680).

[0010] WO2022253967A2 furthermore describes methods to genetically modulate plant adaptation traits to induce heat resistance, as well as increasing growth of the plant at different levels (hypocotyl, root, etc). Unfortunately, these solutions involving genetic modifications are both complex and costly.

[0011] Another strategy to improve plant growth under stress is chemical intervention.

[0012] It is known that some compounds may be used to induce plant tolerance to abiotic stresses and help plants survive such periods, however, at the expense of growth rate and yield, since plant’s energy is focused on survival mechanisms. For instance, exogenous application of different compounds, such a thiourea (TU), have already been described to stimulate defense mechanisms in plants under abiotic stress, according to Waqas M. A. etal., in “Potential Mechanisms of Abiotic Stress Tolerance in Crop Plants Induced by Thiourea”, Front. Plant Sci., 2019, vol. 10, p.1336. However, plant responses vary by plant species and depend on the concentration applied, since, for instance, high doses of TU can cause severe injury to wheat plants.

[0013] Accordingly, from what is known in the art, there is still a need to find non-toxic compounds for different plant species which biostimulate their development and growth, in particular, when exposed to abiotic or biotic stress. This would help overcome the serious threat posed by abiotic and biotic stresses on the sustainability of food production systems.Summary of Invention

[0014] Inventors have found that certain isoflavone derivatives can be used to increase growth and / or yield of several plant species including relevant crops at different developmental stages along the plant life cycle in normal and multiple adverse environmental conditions. It has been shown, for instance, an increase in growth and production, flowering promotion, fruit setting, biomass of mature plants and an accelerated seedling growth and germination rate. Furthermore, these compounds also provide a protective effect on several plant species against abiotic stresses, at different developmental stages, and additionally, may have a positive impact on growth rate, biomass, yield and may even enable fast recovery to severe drought periods, resulting in a higher recovery percentage of the tested plants. They may also provide a protective effect on several plant species against biotic stresses, at different developmental stages.

[0015] Therefore, these compounds are advantageous because they represent a new opportunity to increase growth rate and / or plant yields, and, in particular, to help them overcome drought, floods, cold and heat stress periods, particularly when applied as a preventive treatment before physiological symptoms of plant stress, which are ever-more frequent and prolonged due to climate change.

[0016] Accordingly, a first aspect of the present invention relates to the use of a compound of formula (I) or an agriculturally acceptable salt thereof, either for promoting growth, yield, flowering, fruit set, or a combination of any of them of a plant at any development stage; or for protect plants against abiotic and biotic stresses at any developmental stage; in all cases as compared to the non-treated plant of the same species and at the same developmental stage.

[0017]

[0018] (I)

[0019] wherein: Ri, R12, and R13 are radicals independently selected from H, halogen, OR14, NR14R15, SR14, (Ci-C4)-alkyl, and (Ci-C4)-alkoxy; X is a biradical or a triradical selected from O, S, and NRie; the atom joined to the naphthalene is joined to any of the carbons to which R12 and R13 are attached, and the corresponding radical of this carbon is absent,and R2-R11 are radicals independently selected from H, halogen, OH, NH2, NO2, SH, (C1-C6)-alkyl, O-(Ci-C6)-alkyl, NH-(Ci-C6)-alkyl, S-(Ci-C6)-alkyl, (C3-C6)-cycloalkyl, phenyl, -(Ci-C3)-alkyl-NHRi6, -(Ci-C3)-alkyl-COH, -(Ci-C3)-alkyl-CO-(Ci-C3)-alkyl and chlorophenyl; R14 and R15 are radicals independently selected from H, (Ci-Ce)-alkyl, (C3-C6)-cycloalkyl, phenyl, and chlorophenyl; and R16 is selected from the group consisting of H, (Ci-Ce)-alkyl, and (C3-C6)-cycloalkyl.

[0020] A second aspect of the invention relates to a compound of formula (h) or an agriculturally acceptable salt thereof;

[0021]

[0022] (h)

[0023] wherein: R1’, Rn’ and R12’ are radicals independently selected from H, halogen, OR14, NR14R15, SH, (C2-C4)-alkyl, and (Ci-C4)-alkoxy; X is a biradical or a triradical selected from O, S, and NRie; the atom joined to the naphthalene is joined to any of the carbons to which R11’ and R12’ are attached, and the corresponding radical of this carbon is absent, and R2’-R ’are radicals independently selected from H, halogen, OH, NH2, NO2, SH, (C1-C6)-alkyl, O-(Ci-C6)-alkyl, NH-(Ci-C6)-alkyl, S-(Ci-C6)-alkyl, (C3-C6)-cycloalkyl, phenyl, -(Ci-C3)-alkyl-NHRi6, -(Ci-C3)-alkyl-COH, -(Ci-C3)-alkyl-CO-(Ci-C3)-alkyl and chlorophenyl; R14-R15 are radicals independently selected from H, (Ci-Ce)-alkyl, (C3-Ce)-cycloalkyl, phenyl, and chlorophenyl; R16 is selected from the group consisting of H, (C1-Ce)-alkyl, and (C3-C6)-cycloalkyl and

[0024] with the proviso that compound of formula (h) is other than:

[0025] 7-hydroxy-3-(2-naphthyloxy)-4H-chromen-4-one (la);

[0026] 7-hydroxy-2-methyl-3-(2-naphthyloxy)-4H-chromen-4-one (lb), and

[0027] 7-hydroxy-3-(1-naphthyloxy)-4H-chromen-4-one (If).

[0028] The compound 7-hydroxy-3-(2-naphthyloxy)-4H-chromen-4-one (la) has the CAS number 370841-16-0, the formula below, and has been disclosed by Zhang, Liying etal., “Discovery of novel antimalarial compounds enabled by QSAR-based virtual screening” Journal of Chemical Information and Modeling, 2013, vol. 53, pp.475-492. The compound 7-hydroxy-2-methyl-3-(2-naphthyloxy)-4H-chromen-4-one (lb) has the CAS number328018-29-7, the formula below, and has been disclosed in US20090163545A1. Finally, the compound 7-hydroxy-3-(1-naphthyloxy)-4H-chromen-4-one (If) has the CAS number 383377-31-9, the formula below, but as far as the inventors know there is no reference citing this compound.

[0029]

[0030] A third aspect of the present invention relates to an agrochemical composition comprising an effective amount of the compound of formula (h) as defined above, together with appropriate amounts of one or more agricultural excipients or carriers, wherein the effective amount is either for promoting growth, yield, flowering, fruit set, or a combination of any of them of a plant at any development stage; or for protect plants against abiotic and biotic stresses at any developmental stage; in all cases as compared to the nontreated plant of the same species and at the same developmental stage.

[0031] Brief Description of Drawings

[0032] FIG. 1 shows phenotyping of the hypocotyl in 6-day-old seedlings wild type (WT) Arabidopsis seedlings exposed to 5 pM of one of the compounds of the invention (la), (lb), and (Ic) at 22°C and 28 °C.

[0033] FIG 2 shows thermo-morphogenesis response (percentage hypocotyl growth change relative to non-treated) of Arabidopsis seedlings when exposed to 5 pM of one of the compounds of the invention, (la), (lb), and (Ic).FIG. 3 shows germination of cereal sorghum after four days in water (control) or supplemented with 0.5 pM of compound (la).

[0034] FIG. 4 shows root length (mm) of four-day-old seedlings of cereal sorghum germinated in water (control) or supplemented with 0.5 pM of compound (la).

[0035] FIG. 5 shows germination (%) of commercial tomato cv " Marmande” after 5 days germination in water (control) or supplemented with 0.5 pM of compound (la).

[0036] FIG. 6 shows the distribution 7-day-old shoots lengths of sorghum seedlings with no treatment (control) and treated with compound (la) (0.5 pM), in normal conditions and under osmotic stress conditions (liquid media containing sorbitol).

[0037] FIG. 7 shows phenotype of 7-day-old Arabidopsis seedlings with no treatment (WT) and treated with 5 pM of one of the compounds of the invention (la), (lb), (Ic), in normal conditions (N, untreated media) or stress (S, sorbitol) conditions.

[0038] FIG. 8 shows distribution of 7-day-old Arabidopsis seedlings root lengths (cm) in normal conditions (N, untreated media) or stress (S, sorbitol) conditions.

[0039] FIG. 9 shows phenotype of commercial tomato non-treated plants (control) and treated by foliar application with 2 pM of one of the compounds of the invention (la), (lb) and (Ic), during recovery period after 15 days of severe drought.

[0040] FIG. 10 shows survival rate (%) of commercial tomato “Marmande” non-treated plants (control) and treated by foliar application with 2 pM of one of the compounds of the invention (la), (lb) and (Ic), after a severe period of drought (15 days).

[0041] FIG. 11 shows photosynthesis parameters (Fv / Fm) at day 1 (D1) and day 6 (D6) of severe drought period comparing commercial tomato “Marmande” non-treated plants (control) and treated by foliar application with 2 pM of one of the compounds of the invention (la), (lb), and (Ic).

[0042] FIG. 12 shows the distribution of photosynthesis parameters (Fv / Fm) for commercial tomato “Marmande” treated by foliar application with 2 pM of one of the compounds of the invention (la), (lb), and (Ic), at day 1 (D1) and day 6 (D6) of severe drought period.

[0043] FIG. 13 shows plant size of two-week-old wheat plants (mature) treated with 2 pM of compound (la) (foliar treatment) versus control (without treatment) after 15-day droughtperiod.

[0044] FIG. 14 shows biomass (g) after 15 days without water, comparing two-week-old wheat plants (mature) treated with 2 pM of compound (la) (foliar treatment) versus control (without treatment).

[0045] FIG. 15 shows grain production (g) per plant after recovery of severe drought stress (20 days without water) of two-week-old wheat plants (mature) treated with 2 pM of compound (la) (foliar treatment) versus control (without treatment).

[0046] FIG. 16 shows log10(RC, relative change) of osmoprotectant metabolites induction (where SA is succinic acid, QA is 3-O-Caffeolyquinic acid, O is ornithine, IM is insitol myo, G is glutamine, and A is alanine) in WT Arabidopsis seedlings incubated with compound (la) (50 pM) for 4 days versus non-treated seedlings (WT control), where ** is pvalue<0.025, and * is pvalue<0.05.

[0047] FIG 17 shows fruit set of untreated plants (control) and treated with 25 pM of the compounds of the invention (la) at 30 days after application

[0048] FIG 18 show number of grape clusters per plant in untreated (control ) and treated conditions (la) at 30 days after treatment (N=30)

[0049] FIG. 19 shows grape clusters (control) and treated by foliar application with 25 pM of the compounds of the invention (la) at 60 days after treatment application.

[0050] FIG. 20 shows grape cluster biomass (g) of control (without treatment) and treated with 25 pM of the compounds of the invention (la) at 60 days after application (N=10)

[0051] FIG. 21 shows phenotype of commercial tomato non-treated plants (control) and treated by foliar application with 2 pM of the compounds of the invention (Id) during recovery period after 15 days of severe drought.

[0052] FIG. 22 shows survival rate (%) of commercial tomato “Marmande” non-treated plants (control) and treated by foliar application with 2 pM of the compounds of the invention (Id), after a severe period of drought (15 days).

[0053] FIG. 23 shows phenotype of tomato “Marmande” treated by fertirrigation with (le) at 5 pM, (If) at 1 pM, (Ig) at 5 pM and a control (C) after a severe period of drought followed by two weeks of recovery (normal water).FIG. 24 shows aerial (FIG. 24A) and root (FIG. 24B) biomass of commercial tomato “Marmande” plants after a severe period of drought followed by two weeks of recovery (normal water) treated by fertirrigation with (le) at 5 pM, (If) at 1 pM, (Ig) at 5 pM.

[0054] FIG. 25 shows plant height of commercial tomato “Marmande” plants after a severe period of drought followed by two weeks of recovery (normal water) treated by fertirrigation with with (le) at 5 pM, (If) at 1 pM, (Ig) at 5 pM and untreated

[0055] FIG.26 shows phenotyping of the hypocotyl in 6-day-old seedlings wild type (WT) Arabidopsis seedlings exposed to 50 pM of one of the compounds of the invention (le), (Ig), (Ih), (li), (lj) at 28 °C.

[0056] FIG 27 shows thermo-morphogenesis response (percentage hypocotyl growth change relative to non-treated) of Arabidopsis seedlings when exposed to 50 pM of one of the compounds of the invention (le), (Ig), (Ih), (li) and (Ij).

[0057] FIG. 28 shows phenotype of tomato “Marmande” treated by fertirrigation with (Ih) and (li) at 5 pM after a severe period of drought followed by two weeks of recovery (normal water).

[0058] FIG. 29 shows aerial (FIG 29A) and root biomass (FIG 29B) of commercial tomato “Marmande” after a severe period of drought followed by two weeks of recovery (normal water) treated by fertirrigation with (Ih) at 5 pM and (li) 5 pM.

[0059] FIG. 30 shows plant height of commercial tomato “Marmande” after a severe period of drought followed by two weeks of recovery (normal water) treated by fertirrigation with with (Ih) at 5 pM and (li) at 5 pM

[0060] Detailed description of the invention

[0061] All terms as used herein in this application, unless otherwise stated, shall be understood in their ordinary meaning as known in the art. Other more specific definitions for certain terms as used in the present application are as set forth below and are intended to apply throughout the description and claims.

[0062] As used herein, the indefinite articles “a” and “an” are synonymous with “at least one” or “one or more.” Unless indicated otherwise, definite articles used herein, such as “the,” also include the plural of the noun.

[0063] The word “comprise” for the purposes of the present invention encompasses the case ofconsisting essentially of” and “consisting of”.

[0064] In the context of the present invention, when referring to “compounds of formula (I)” and / or “compounds of formula (h)”, its stereoisomers and its salts are included.

[0065] The term “halogen” is meant to include the chemically related elements fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).

[0066] The expression "effective amount" as used herein, refers to the amount of a compound that, when administered, is sufficient to increase growth and / or yield of a plant to some extent and / or flowering of a plant, at any developmental stage. It can be considered sufficient to protect a plant against stress, without hindering its developmental and / or growth process. The particular dose of the compound administered according to this invention will of course be determined by the particular circumstances surrounding the case, including the compound administered, its administration method, the particular species and / or developmental stage of the plant, the particular abiotic stress against which the compound protects the plant, and the similar considerations.

[0067] The expression "agriculturally acceptable excipients or carriers" refers to agriculturally acceptable materials, compositions, or vehicles. Each component must be agriculturally acceptable in the sense of being compatible with the other ingredients of the composition. It must also be suitable for use in contact with the plant without excessive toxicity or other problems or complications commensurate with a reasonable benefit / risk ratio.

[0068] Within the context of this specification, “a plant adaption trait” or “a plant trait” is defined as at least one of the following: the growth physiology, the tolerance to an abiotic stress, a vascular transport and / or the defence response.

[0069] A “wild-type” or “normal” or “untreated” or “control” or “reference” plant in this specification is meant to comprise a plant that has not been genetically modified nor has been treated with a compound that may induce its tolerance to stress or affect its growth development. In the context of the present invention these terms are interchangeably and are regarded as synonyms. A control plant in this specification may also be a plant known to the person skilled in the art to be sensitive to stress, which can be abiotic stress, such as heat, osmotic, cold, freeze, floods and / or drought stress, or biotic stress, such as those produced by a living organism.

[0070] Within the context of this specification, a “biotic stress” is defined as the negative impact caused by a living organism or pathogen, such as bacteria, viruses, fungi, parasites, andinsects, on another living organism, such as a plant. The negative impact caused by biotic stress may also refer to a decrease in yield or growth of the plant due to competition with weeds. Examples of biotic stress may include those produced by a living organism selected from the group consisting of bacteria, viruses, fungi, parasites, and insects.

[0071] As mentioned above, the use of a compound of formula (I) or an agriculturally acceptable salt thereof, either for promoting growth, yield, flowering, fruit set, or a combination of any of them of a plant at any development stage; or for protect plants against abiotic and biotic stresses at any developmental stage; in all cases as compared to the non-treated plant of the same species and at the same developmental stage,

[0072]

[0073] (I)

[0074] wherein: Ri, R12, and R13 are radicals independently selected from H, halogen, OR14, NR14R15, SR14, (Ci-C4)-alkyl, and (Ci-C4)-alkoxy; X is a biradical or a triradical selected from O, S, and NRie; the atom joined to the naphthalene is joined to any of the carbons to which R12 and R13 are attached, and the corresponding radical of this carbon is absent, and R2-R11 are radicals independently selected from H, halogen, OH, NH2, NO2, SH, (C1-C6)-alkyl, O-(Ci-C6)-alkyl, NH-(Ci-C6)-alkyl, S-(Ci-C6)-alkyl, (C3-C6)-cycloalkyl, phenyl, -(Ci-C3)-alkyl-NHRi6, -(Ci-C3)-alkyl-COH, -(Ci-C3)-alkyl-CO-(Ci-C3)-alkyl and chlorophenyl; Ri4 and R15 are radicals independently selected from H, (Ci-Ce)-alkyl, (C3-C6)-cycloalkyl, phenyl, and chlorophenyl; and R16 is selected from the group consisting of H, (Ci-Ce)-alkyl, and (C3-C6)-cycloalkyl, is part of the invention.

[0075] The expression “agriculturally acceptable salt” refers to any salt formed, provided that it is a non-toxic salt for plants, in the present with an organic or inorganic cation or with an organic or inorganic anion. Suitable agriculturally useful salts are those formed with cations and anions that do not have any adverse effect on the action of the compounds according to the present invention.

[0076] Examples of suitable cations are alkali metals, such as lithium, sodium, and potassium,alkaline earth metals such as calcium, magnesium, and barium, and transition metals, such as manganese, copper, zinc, and iron. Other examples of suitable salts include methylamine, dimethylamine, triethylamine, triethanolamine, ethylenediamine, tris(hydroxymethyl)methylamine, and those formed with ammonium (NH4+) and substituted ammonium, such as ethylammonium, isopropylammonium, dimethylammonium, diisopropylammonium, trimethylammonium, tetramethylammonium, tetraethylammonium, tetrabutylammonium, 2-hydroxyethylammonium, 2-(2-hydroxyethoxy)ethylammonium, bis(2-hydroxyethyl)ammonium, benzyltrimethylammonium, and benzyltriethylammonium. Other suitable cations include phosphonium and sulfonium ions, such as tri(Ci-C4-alkyl)sulfonium, and sulfoxonium ions such as tri(Ci-C4- alkyl)sulfoxonium.

[0077] Examples of suitable anions include chloride, bromide, fluoride, hydrogen sulphate, sulphate, dihydrogen phosphate, hydrogen phosphate, phosphate, nitrate, citrate, hydrogen carbonate, carbonate, hexafluorosilicate, hexafluorophosphate, benzoate, besylate, maleate, Ci-Ce carboxylate, such as formate, acetate, propionate, and butyrate.

[0078] The compounds of formula (I) or their salts, or their stereoisomers, can exist in solvated, as well as unsolvated forms, including hydrated forms. Thus, they can contain in its structure stoichiometric amounts of solvent in the case of solvates, or of water in the case of hydrates. It is to be understood that the invention encompasses all such solvated, as well as unsolvated forms.

[0079] In a particular embodiment of the use as defined above, the compounds of formula (I) are those wherein X is O, having the formula (I’), wherein: Ri-Riahave the same meaning as in formula (I).

[0080] o

[0081] K2

[0082]

[0083] (I’)

[0084] In another particular embodiment, the compounds of formula (I’) are those where in OR14, NR14R15, SR14, Ri4is H.In another particular embodiment of the use according to the invention, the compounds of formula (I’) are those having formula (I”) where R1-R12 have the same meaning as in formula (I’).

[0085] R o o

[0086] 10 ^11K2

[0087]

[0088] (I”)

[0089] In another particular embodiment of the use according to the invention, the compounds of formula (I”) as defined above, are those where R3 is OH.

[0090] In another particular embodiment of the use according to the invention, the compounds of formula (I) are selected from the following list:

[0091] 7-hydroxy-3-(2-naphthyloxy)-4H-chromen-4-one (la);

[0092] 7-hydroxy-2-methyl-3-(2-naphthyloxy)-4H-chromen-4-one (lb),

[0093] - 7-hydroxy-2-methyl 3-(1-naphthyloxy)-4H-chromen-4-one (Ic),

[0094] 7-hydroxy-3-(2-naphthylsulfanyl)-4H-chromen-4-one (Id)

[0095] 7-hydroxy-3-(2-naphthylsulfanyl)chromen-4-one (le),

[0096] 7-hydroxy-3-(1-naphthyloxy)chromen-4-one (If)

[0097] 5,7-dihydroxy-3-(2-naphthyloxy)chromen-4-one (Ig),

[0098] - 7-hydroxy-3-[(7-methyl-2-naphthyl)oxy]chromen-4-one (Ih),

[0099] 3-[(6-chloro-2-naphthyl)oxy]-7-hydroxy-chromen-4-one (li), and

[0100] 7-hydroxy-3-[(1-nitro-2-naphthyl)oxy]chromen-4-one (Ij).

[0101] and having the following structures:

[0102]

[0103]

[0104] The present invention also relates to a method to increase growth and / or yield and / or flowering of a plant, at any developmental stage, as compared to the non-treated plant of the same species and at the same developmental stage, comprising administering an effective amount of a compound of formula (I) or an agriculturally acceptable salt thereof, as defined above.All the particular embodiments of the use of the invention are also embodiments of the method to increase growth and / or yield and / or flowering of a plant, at any developmental stage, as compared to the non-treated plant of the same species and at the same developmental stage, comprising administering an effective amount of a compound of formula (I) or an agriculturally acceptable salt thereof, as defined above.

[0105] In a particular embodiment, the use of the compounds of formula (I) as defined above is to increase growth and / or yield of a plant, at any developmental stage, as compared to the non-treated plant of the same species and at the same developmental stage.

[0106] In another particular embodiment, the use of the compounds of formula (I) as defined is to promote flowering, and fruit setting.

[0107] It is particularly surprising and advantageous that the compounds of the invention, as shown in the Examples, are not only capable of accelerating growth and development rates of plants, in particular when applied to seeds, seedlings or mature plants, which are cultivated under optimal conditions, but most importantly, they are capable of enabling plants to maintain growth and development rates and yield even when the plant is subject to abiotic conditions, such as floods, drought, heat and / or osmotic stress. In comparison to a genetically modified plant, the present invention offers several advantages, not only from an economic perspective, but also for the simplicity of application of the compounds of the invention, at any developmental stage of the plant, and by well-known application methods.

[0108] Thus, in a particular embodiment of the use of the compounds of formula (I) as defined above, in combination with any of the embodiments above or below, the plant is a plant subject to an abiotic stress, and the use further comprises an increase in the adaptability of the plant to an abiotic stress. In a more particular embodiment of the use of the compounds of formula (I) as defined above, the abiotic stress is selected from the group consisting of floods, heat stress, drought stress, cold stress and osmotic stress.

[0109] In another embodiment of the use of the compounds of formula (I) as defined above, in combination with any of the embodiments above or below, the plant is a plant subject to a biotic stress, and the use further comprises an increase in the adaptability of the plant to a biotic stress. In a more particular embodiment of the use of the compounds of formula (I) as defined above, the biotic stress of the plant is that which is produced by a living organism selected from the group consisting of bacteria, viruses, fungi, parasites, and insects.The expression “osmotic stress” response is meant to encompass a degree of adaptation to a sudden change in the solute concentration to which the plant it is exposed. Such osmotic stress might be provoked by an increased ion concentration {e.g. increased salinity, heavy metals) or decreased water contents which are mostly the results of drought or salinity / salt stress. Osmotic stress will result in a decreased water potential in the leaves of the plant and reduced turgor pressure in the cells. Osmotic stress includes changes in turgor, cell wall stiffness and integrity, membrane tension, and cell fluid volume at cellular level reducing plants growth and production.

[0110] The expression “drought tolerant” is meant to encompass a degree of adaptation to arid or drought conditions, reduced water availability or stress factors associated therein. Drought or water stress, for the purpose of this invention, is an extended period of time of 1 to 13 days, or 2 to 13 weeks, or longer, wherein a plant receives less water and is hence under drought stress.

[0111] In a particular embodiment of the use of the compounds of formula (I) as defined above, in combination with any of the embodiments above or below, the plant receives less water than normal, for example 0.5% to 80% less water or less compared to normal or average conditions.

[0112] Drought is known to vary in length depending on the plant species and the conditions it typically grows in. Typically, a drought sensitive plant has a decreased survival rate of at least 5% to 90% or more during drought or after a drought period when compared to the survival rate of said plant when not exposed to drought. A drought resistant plant, a drought tolerant plant, a plant that survives longer during or after water or drought stress, and a plant with improved survival and / or growth during or after a drought or water stress period in the context of this application are considered synonymous to each other and used interchangeably.

[0113] Typically, an abiotic stress sensitive plant has a decreased survival rate, a reduced fertility and / or yield loss of at least 5% to 90% or more during or after a heat, osmotic, cold and / or drought stress period when compared to the survival rate, fertility and / or yield of said plant when not exposed to an abiotic stress.

[0114] Similarly, a biotic stress sensitive plant has a decreased survival rate, a reduced fertility and / or yield loss of at least 5% to 90% or more during or after a stress period produced by a living organism, when compared to the survival rate, fertility and / or yield of said plant when not exposed to a biotic stress.In a particular embodiment of the use of the compounds of formula (I) as defined above, in combination with any of the embodiments above or below, an abiotic stress sensitive plant treated with compounds of the invention may exhibit a growth adaptation to such stress. For instance, Example 4 shows enhanced growth in wheat seedlings treated with compounds of the invention and subjected to osmotic stress, showing longer roots and shoots than control wheat seedlings cultivated under the same conditions.

[0115] Likewise, mature plants treated with the compounds of the invention and subject to heat stress showed higher survival rate compared to the non-treated plants, as well as higher levels of photosynthesis rate, indicating a better performance during stress conditions.

[0116] “Heat stress” and “elevated temperature” are synonymous in the context of the application. “Heat stress” or “elevated temperature”, for the purpose of this invention, is an extended period of time of at least 1 to 13 days, or 2 to 13 weeks, or longer, wherein the temperature is higher than the temperature under normal or average conditions, which may also be called the optimum growth temperature. This is the temperature at which a plant will grow the best. Such optimum temperature is different for each plant species / variety. The temperature is higher than the temperature under normal or average conditions when it is at least 1 to 15 degrees Celsius higher than the optimum growth temperature for each species or variety.

[0117] Obviously, “heat stress” is plant species specific and one plant species may experience a “heat stress” at a given temperature while another plant species will not experience such a “heat stress” at the same temperature. As soon as a plant (or plant species) has a decreased survival rate, reduced fertility and / or yield loss of at least 5% to 90% or more after a period of from 1-15 days during which said period the temperature is at least 1 to 15 degrees Celsius higher than the optimum growth temperature, one can say that this plant is sensitive for heat stress.

[0118] “Cold stress” and “low temperature” are synonymous in the context of the application. “Cold stress” or “low temperature”, for the purpose of this invention, is an extended period of at least 1 to 13 days, or 2 to 13 weeks, or longer, wherein the temperature is lower than the temperature under normal or average conditions, which may also be called the optimum growth temperature. This is the temperature at which a plant will grow the best. Such optimum temperature is different for each plant species / variety. Cold stress is characterized by three temperature ranges that are common for plant cultivation: (1) freezing (<0 °C), (2) chilling (>0 °C to growth limit), and (3) suboptimum (growth limit to optimum) conditions. Cold stress is characterized by three temperatures zones that are common for plant cultivation: (1) freezing (<0 °C), (2) chilling (>0 °C to growth limit), and(3) suboptimum (growth limit to optimum) conditions.

[0119] Obviously, “cold stress” is plant species specific and one plant species may experience a “cold stress” at a given temperature while another plant species will not experience such a “cold stress” at the same temperature. As soon as a plant (or plant species) has a decreased survival rate, reduced fertility and / or yield loss of at least 5% to 90% or more after a period of from 1-15 days during which said period the temperature is in any of the above-defined zones (1), (2) or (3), one can say that this plant is sensitive for cold stress.

[0120] The treated plants with the compounds of the present invention are resistant or tolerant to heat and cold stress, showing improved survival rate, fertility, growth and / or yield compared to the control plant as previously defined. The improvement is of at least 5% to 90% or more measured during the same period of time and under the same stress conditions.

[0121] Heat stress tolerance in this specification is meant to encompass a degree of adaptation to heat or elevated temperatures or stress factors associated with elevated temperatures. Examples of stress factors associated with heat or elevated temperatures include increased light intensity, increase of factors associated with greater water evaporation from soil such as decreased water availability or increase in soil solute (salt) concentrations. A plant that survives longer during or after heat stress and a plant with improved survival or growth during or after a heat period in the context of this specification are considered synonymous to each other and used interchangeably.

[0122] Cold-stress tolerance in this specification is meant to encompass a degree of adaptation to cold or low temperatures, freezing or stress factors associated with low temperatures. In chillling temperatures plants can be affected at any developmental stage, observed in the form of chlorosis, stiffness of seedlings, withering and often the death of

[0123] seedlings. Effects can range from slight delays in development from growth inhibition to plant death. Other commonly observed stress responses include leaf chlorosis and necrotic lesions. Many physiological processes in plants are impeded by low temperatures, such as photosynthetic capacity, membrane rigidity, transpiration, and enzyme activity (Ritonga FN, Chen S. Physiological and Molecular Mechanism Involved in Cold Stress Tolerance in Plants. Plants (Basel), 2020, vol. 9(5), p. 560). Together, these physiological effects of cold stress can result in poor agronomic performance. A plant that survives longer during or after cold stress and a plant with improved survival or growth during or after a cold period in the context of this specification are considered synonymous to each other and used interchangeably.In a particular embodiment of the use of the compounds of the present invention, in combination with any of the embodiments above or below, the tolerance of the plant to an abiotic stress (preferably floods, heat, osmotic, cold and / or drought stress) has been improved, in that the plant may have an improved root hydrotropism, an enhanced programmed cell death in root meristems under osmotic stress, a greater hypocotyl growth, a greater petiole elongation, improved survival rate, an improved carbon utilization and / or reduced or repressed photorespiration pathway signaling in normal conditions and under heat stress, and / or a capacity to accumulate metabolites in normal conditions and under heat stress.

[0124] In a particular embodiment of the use of the compounds of the present invention, in combination with any of the embodiments above or below, the growth physiology of the treated plant, whether it is subjected or not to an abiotic stress, may be different to that of the control plant in that the treated plant may have an increased hypocotyl growth, an increased root growth, an increased petiole length, an altered flowering time and / or a modulation of a marker gene involved in phytohormone response, among other.

[0125] Preferably, the hypocotyl growth of said plant is increased by at least 5% to 90% or higher when compared to the corresponding percentage of a control or reference plant under the same conditions. Preferably, the root growth of said plant is increased by at least 5% to 90% or higher when compared to the corresponding percentage of a control or reference plant under the same conditions.

[0126] Improved growth can be seen as increased accumulated biomass or increased average accumulated biomass. For example, the biomass of treated plants as envisioned by the invention compared to the biomass of wild-type plant is higher by 5% to 90% or more. Biomass can be determined be weighing the entire plant or a specified part thereof, such as roots, stem, stalk, leaves, fruit, seeds, or a combination thereof.

[0127] Within the context of this invention, a plant with improved root hydrotropism is defined as a plant with an increase in average or mean root curvature distribution, or an increase in percentage of roots with a curvature close to 180 degrees (Takahashi N et al., “Hydrotropism in abscisic acid, wavy, and gravitropic mutants of Arabidopsis thaliana”, Planta, 2002, vol. 216(2), pp. 203-211). Preferably, a plant with improved root hydrotropism contains a root curvature distribution where the percentage of roots with an angle between 160 and 180 degrees is increased by at least 5% to 90% or higher when compared to the corresponding percentage of a normal or wild-type plant under the same conditions (period of time and drought). Root curvature can be measured by growing seedlings vertically on MS standard medium or 1 MS standard medium and treated during 24-48h or during 30 min to 24 hours in a gradient concentration of sorbitol,subsequently measuring 3 to 10-day old seedling root curvature and analyzing the angle in Image J software. 14 MS standard medium is MS standard medium, which has been, diluted 14.

[0128] Within the context of the invention, the vascular transport properties of the treated plant according to the invention have been improved when plants treated with the compounds of the invention are compared to control plants, and the treated plant exhibits an increased accumulation of metabolites, as shown in Example 15. Such metabolites may be osmoprotectant and / or relevant for the plant stress response and nutrient efficiency. Examples of such metabolites include sucrose, trehalose, ornithine, urea, proline, arginine, galacturonic acid, glycerol, erythritol, glutamine, maleic acid and beta alanine. Within the context of this invention, a plant exhibiting an increased accumulation of metabolites, wherein the length of the root is an indication of the status of the accumulation of metabolites, an increase of the length of the root usually correlating with an increased accumulation of metabolites. In a particular embodiment of the use of the compounds of formula (I) as define above, in combination with any of the embodiments above or below, the increase is an increase of at least 5% to 95% or more when compared to the length of the root in a control plant under the same conditions (time and heat and / or water availability).

[0129] Inventors have found, as can be seen in several Examples, that the application of the compounds of the invention, whether it be on plants subject to an abiotic or biotic stress or neither, promote development and growth rates at any stage of the plant’s life. The compounds of the invention have proven to be non-toxic at different dose ranges, for several species and families of plants tested and at different developmental stages, providing moreover benefits for such plants. Thus, in a particular embodiment of the use of the compounds of formula (I) as defined above, in combination with any of the embodiments above or below, the plant is a mature plant. In another particular embodiment of the use of the compounds of formula (I) as defined above, the plant is a seed or a seedling.

[0130] In an embodiment, in combination with any of the embodiments above or below, the compounds of formula (I) to be used as defined above are in form of a solution or a suspension in water.

[0131] In a particular embodiment, in combination with any of the embodiments above or below, the compounds of formula (I) to be used as defined above are in a concentration range from 0.001 nM to 1000 pM in the solution, suspension or emulsion to be administered to the plant. In a more particular embodiment, the compounds of formula (I) to be used asdefined above are in a concentration range from 0.001 pM to 500 pM in the solution or suspension to be administered to the plant. In a more particular embodiment, the compounds of formula (I) for use as defined above are in a concentration range from 0.01 pM to 200 pM in the solution or suspension to be administered to the plant. In a more particular embodiment, the compounds of formula (I) for use as defined above are in a concentration range from 0.5 pM to 50 pM in the solution or suspension to be administered to the plant.

[0132] “Administering" or “applying” in the context of the invention comprises providing the compound (dissolved in water) to the plant by way of spraying or otherwise applying directly on or to the plant, to the seed, by any seed coating or directly to the soil or other support on which the plant is growing, or by dissolving it in the agar medium provided for plant germination.

[0133] In an embodiment, in combination with any of the embodiments above or below, the compounds of the invention are applied to the plant, seed or soil through any administration form, such as injectable, and by any chemical delivery method, such as nanoparticles, conjugated with lipids, or hydrogels.

[0134] In an embodiment, in combination with any of the embodiments above or below, the compounds of the invention are applied to the plant, seed or soil by means of a spray. In a particular embodiment, the spray also comprises a surfactant.

[0135] For the purpose of the invention, an “adult” or “mature” plant, which are synonymous in the context of the application and may be used interchangeably, is defined as a plant of at least 2 weeks old. The person skilled in the art will be aware that the minimal age to reach adulthood may differ depending on the plant species. Depending on the developmental stage of the plant, the compounds of the invention may be applied using different methods, all of which show non-toxicity and effectivity in terms of conferring resistance and promoting growth to the plant. Thus, in a particular embodiment of the use of the compounds of formula (I) as defined above, in combination with any of the embodiments above or below, the plant is a mature plant, and the compounds of formula (I) are applied to the mature plant by foliar application.

[0136] Foliar application is known in the art, however, this method of application has not been described for the use of the compounds of the invention, let alone for the purpose of the present invention. Foliar application for the use of the present invention has proven to be a great method of supplying plant requirements for secondary nutrients and micronutrients, and in this case the compounds of the invention, since they are sprayeddirectly on the leaves and other developed parts of the plant, not only having an impact on the absorption of the compounds, but also simplifying the process. On the other hand, since seeds and / or seedlings have not yet developed, foliar application is not possible and other methods, which have proven to have effect in the Examples, are applied. Thus, in another particular embodiment of the use of the compounds of formula (I) as defined above, in combination with any of the embodiments above or below, the plant is a seed or a seedling, and the compounds of formula (I) are applied to the seed or seedling by immersion, coating, incubation and / or supplementation.

[0137] As mentioned above and as can be seen in the Examples, the compounds of the invention have proven to be non-toxic for several species and families of plants tested and at different developmental stages, providing benefits for such plants in terms of resistance to stress, development and growth rates, and crop yields. The compounds of the invention may be applied to different plant species, in the field of agriculture as well as other fields, including edible and non-edible species.

[0138] In an embodiment, plants to which the compounds of the invention may be applied include, but are not limited to, those belonging to the following groups: crops of cereals, oilseeds and protein crops, forest crops, viticulture, horticulture, sod, flax, cotton, vegetables, fruit gardens, aromatics and spice, arboriculture, and industrially cultivated plants for use in the production of raw materials. In another embodiment, plants to which the compounds of the invention may be applied are selected from the group comprising Rosaceae sp., Ribesioidae sp., Juglandaceae sp., Betulaceae sp., Anacardiaceae sp., Fagaceae sp., Moraceae sp., Pinaceae sp., Oleaceae sp., Actinidaceae sp., Lauraceae sp., Musaceae sp., Rubiaceae sp., Theaceae sp., Sterculiceae sp., Rutaceae sp., Solanaceae sp., Vitaceae sp. Liliaceae sp., Asteraceae sp., Umbelliferae sp., Cruciferae sp., Chenopodiaceae sp., Cucurbitaceae sp., Papilionaceae sp., such as Graminae sp., Fabacae sp., as well as genetically modified homologues of these crops. In another embodiment, the compounds of the invention may be applied to a plant that is a food crop selected from the group comprising wheat, buckwheat, rice, brown rice, lentils, couscous, com, soybean, potato, barley, oat, quinoa, peas, red bean, and millet. In another embodiment, the plant is a vegetable crop selected from the group comprising tomato, radish, cress, cucumber, cabbage, watermelon, melon, cabbage, Chinese cabbage, scallion, onion, carrot, zucchini, and Arabidopsis thaliana. In another embodiment, the plant is a fruit crop selected from the group comprising avocado, apple, pear, date, peach, kiwi, grape, orange, persimmon, plum, apricot, banana, and tangerine. In another embodiment, the plant is a special crop selected from the group comprising mustard, ginseng, tobacco, cotton, sesame, sugar cane, sugar beet, peanut, and rapeseed. In another embodiment, the plant is a flower crop selected from the group comprising rose,gerbera, gladiolus, carnation, chrysanthemum, lily, and tulip. In another embodiment, the plant is a feed crop selected from the group comprising rye grass, red clover, orchard grass, alfalfa, and tall fescue.

[0139] The fact that the compounds show positive effects on different plant families is a great advantage in the field of agriculture, in particular in the fight for maintaining food security in an ever-more inhospitable world for plant cultivation, due to frequent periods of drought and extreme heat associated to climate change. The inventors have found that the compounds of the invention have effect on plant families which are crucial in terms of food and nutrition worldwide, in particular, cereals, such as wheat, solanaceous plants, from which we obtain tomatoes, potatoes, eggplants, among others, and crucifers, from which we obtain, for example, broccoli and cauliflower. Thus, in a particular embodiment of use of the compounds of formula (I) as defined above, in combination with any of the embodiments above or below, the plant family is selected from Brassicaceae, Poaceae, and Solanaceae. In a more particular embodiment of use of the compounds of formula (I) as defined above, the plant genus is selected from Arabidopsis, Solanum, Triticum, Sorghum, Vitis, and Cucurbitaceae.

[0140] A second aspect of the invention relates to a compound of formula (h) or an agriculturally acceptable salt thereof,

[0141]

[0142] (h)

[0143] wherein:

[0144] Ri’, R11’ and R12’ are radicals independently selected from H, halogen, OR14, NR14R15, SH, (C2-C4)-alkyl, and (Ci-C4)-alkoxy;

[0145] X is a biradical or a triradical selected from O, S, and NRie;

[0146] the atom joined to the naphthalene is joined to any of the carbons to which Rn’ and R12’ are attached, and the corresponding radical of this carbon is absent, and R2’-R ’ are radicals independently selected from H, halogen, OH, NH2, NO2, SH, (Ci-Ce)-alkyl, O-(Ci-Ce)-alkyl, NH-(Ci-Ce)-alkyl, S-(Ci-Ce)-alkyl, (C3-C6)-cycloalkyl, phenyl, -(Ci-Csj-alkyl-NHR16, -(Ci-Csj-alkyl-COH, -(Ci-C3)-alkyl-CO-(Ci-C3)-alkyl and chlorophenyl,R14-R15 are radicals independently selected from H, (Ci-Ce)-alkyl, (C3-C6)-cycloalkyl, phenyl, and chlorophenyl, R16 is selected from the group consisting of H, (Ci-Ce)-alkyl, and (C3-C6)-cycloalkyl, is part of the invention;

[0147] with the proviso that compound of formula (11) is other than:

[0148] 7-hydroxy-3-(2-naphthyloxy)-4H-chromen-4-one (la);

[0149] 7-hydroxy-2-methyl-3-(2-naphthyloxy)-4H-chromen-4-one (lb), and

[0150] 7-hydroxy-3-(1-naphthyloxy)-4H-chromen-4-one (If).

[0151] In a particular embodiment, the compound of formula (h) as defined above is that where: in OR14, NR14R15, SR14, R14 is H and the compounds of formula (h) has the formula (h’) wherein R1-R12 have the same meaning as in formula (h),

[0152]

[0153] In another particular embodiment, the compound of formula (h’) as defined above is that where: the oxygen joined to the naphthalene is joined to the carbon to which R12’ is attached, and thus R12’ is absent; R1’ and Rn’are radicals independently selected from H or halogen; and R2’-R ’are radicals independently selected from H, halogen, OH, (Ci-C6)-alkyl, O-(Ci-C6)-alkyl, -(Ci-C3)-alkyl-NHRi6, -(Ci-C3)-alkyl-COH,

[0154] and -(Ci-C3)-alkyl-CO-(Ci-C3)-alkyl.

[0155] In a particular embodiment, the compounds of formula (h’) are those having the formula (h”), where R1’ - Rn’ have the same meaning as defined in formula (h’).

[0156]

[0157] In another particular embodiment, a compound of formula (h) as defined above is administered in the form of a composition, which comprises an effective amount of compound of formula (h) or an agriculturally acceptable salt thereof, together with agriculturally acceptable excipients or carriers.

[0158] Finally, as mentioned above, an agrochemical composition comprising an effective amount of the compound of formula (h) as defined above, together with appropriate amounts of one or more agricultural excipients or carriers is part of the invention, wherein the effective amount of compound of formula (h) is either for promoting growth, yield, flowering, fruit set, or a combination of any of them of a plant at any development stage; or for protect plants against abiotic and biotic stresses at any developmental stage; in all cases as compared to the non-treated plant of the same species and at the same developmental stag, is part of the invention. In a particular embodiment, the composition is an spray.

[0159] The agriculturally acceptable excipients or carriers may include diluents such as lactose monohydrate, talc, extender agents, anticaking agents such as citric acid or calcium sterate, lubricants such as magnesium stearate, disintegrants such as cellulose, stabilisers, antioxidants such as vitamin C or vitamin E, preservatives like thymol, buffers, emulsifiers such as soy lecithin, bittering agents (to protect from the plant predators), colouring agents (to check the distribution of the product), thickeners such as cornstarch, correctors, dissolution aids, and other additives such as water, vegetable oil, alcohols, gelatine, carbohydrates (e.g. lactose, starch, etc.), talc, lanolin, beeswax and the like.

[0160] The compounds of the present invention can be prepared in an analogous way to the compounds described in the examples.

[0161] For example, a-aryloxy-2,4-dihydroxyacetophenones can be prepared from commercially available compounds by Houben-Hoesch condensation, using for instance hydrogen chloride, and with Resorcinol or Phloroglucinol in the presence of zinc chloride.

[0162] The preparation of 3-phenoxy chromone can be achieved by cyclisation of the intermediate ketone under Vilsmeier conditions whereas 2-methyl substituted chromones can be obtained by reaction of the corresponding ketones with acetic anhydride in the presence of triethylamine and subsequent deacetylation in acidic conditions.

[0163] Throughout the description and claims the word “comprise” and variations of the word, are not intended to exclude other technical features, additives, components, or steps.

[0164] Furthermore, the word “comprise” encompasses the case of “consisting of”. Additional objects, advantages and features of the invention will become apparent to those skilled inthe art upon examination of the description or may be learned by practice of the invention. The following examples and drawings are provided by way of illustration, and they are not intended to be limiting of the present invention. Reference signs related to drawings and placed in parentheses in a claim, are solely for attempting to increase the intelligibility of the claim and shall not be construed as limiting the scope of the claim. Furthermore, the present invention covers all possible combinations of particular and preferred embodiments described herein.

[0165] Abbreviations

[0166] Wild type (WT), materials and methods (MM), interquartile range (IQR).

[0167] Materials and methods

[0168] MM.1. Sterilized Arabidopsis seeds (Col-0) were vernalized at 4°C for 48h and germinated in 0.5MS soft agar media + 5 pM of one of the compounds of the invention (la), (lb), and (Ic) at 22 °C or 28°C. Hypocotyl length was measured after 6 days at 28°C or 22°C light intensity around 120 pmoles / m2 / s and 60% relative humidity.

[0169] MM.2. Sterilized Sorghum (Sorghum bicolor) TX430 seeds were soaked in plates with a primming solution of 0.5 pM of compound (la) (treatment), or with water (control) at 28°C for germination. After 4 days the number of germinated seeds and the length of the root and aerial part was measured. The experiment was performed with 12 seeds per treatment and 3 independent replicas.

[0170] MM.3. Sterilized tomato commercial variety " Marmande" were soaked in plates with a primming solution of 0.5pM of one of the compounds of the invention (la), (lb), and (Ic) (treatment), or water (control) at 24°C for germination. After 3 days the number of germinated seeds and the length of the root and aerial part were measured. The experiment was performed with 20 seeds per treatment and 3 independent replicas.

[0171] MM.4. Sterilized and germinated Sorghum (Sorghum bicolor) TX430 were primed with a 0.5 pM solution of compound (la) (treatment) or with water (control). Three day-old-seedlings transferred either to control or to 270 mM sorbitol for 72h. Root and aerial part length was measured after 72h of treatment.

[0172] MM. 5. Sterilized Arabidopsis seeds were vernalized at 4°C for 48h and germinated in 0.5MS agar at 22°C. Seedlings of 3-day-old were transferred to either control or 270 mMsorbitol media with the addition of 5 pM of one of the compounds of the invention (la), (lb), and (Ic), or without treatment. Root length was measured after 4 days of treatment

[0173] MM.6. Sterilized tomato commercial variety " Marmande" were germinated at 24°C for germination and transferred to pots containing (3:1:1 turba, vermiculite, perlite). Two-week old plants were treated by foliar application with a 2pM solution of one of the compounds of the invention (la), (lb), and (Ic), or with water (control). Formulation containing the compound and Tween 20 at 0.01% emulsifier were sprayed on leaves till run off. A solution of Tween 20 at 0.01% was used as control. After two daily applications, plants were subjected to severe drought stress by withholding water for 15 days followed by rewatering for the following 2 weeks. After 15 days of recovery: biomass, survival rate and photosynthesis parameters were measured. The experiment was performed with 10 plants and 3 independent replicas.

[0174] MM.7. Sterilized wheat commercial variety " Tocayo" were germinated at 24°C. Five-day-old seedlings were transferred to pots containing (3:1:1 turba, vermiculite, perlite). Two-week-old plants were treated by foliar application with a 2 pM solution of compound (la) or with water (control). Formulation containing the compound and Tween 20 at 0.01% emulsifier were sprayed on leaves till run off. A solution of Tween 20 at 0.01% was used as control. After two daily applications, plants were subjected to severe drought stress by withholding water for 20 days followed by re-watering for 5 weeks. Biomass and yield were followed during the stress and the recovery period. The experiment was performed with 12 plants per treatment.

[0175] MM 8. Grapevine plants commercial variety " Merlot" were treated by foliar application with a 25 pM solution of compound (la) or with water (control). Formulation containing the compound and Tween 20 at 0.01% emulsifier were sprayed on leaves till run off.

[0176] Application was performed before flowering and a second application performed after 30 days. Flowering and fruit production was followed along a time course (30 and 60 days after treatment). The experiment was performed with 75 plants per treatment.

[0177] MM 9. Sterilized tomato commercial variety " Marmande" were germinated at 24°C for germination and transferred to pots containing (3:1:1 turba, vermiculite, perlite). Two-week old plants were treated by fertirrigation with a 1 or 5pM solution of one of the compounds of the invention (le), (If), and (Ig), or with water (control). Formulation containing the compound was added to the soil. After the priming treatment, plants were subjected to severe drought stress by withholding water for 11-13 days followed by re-watering for the following 2 weeks. After 15 days of recovery: biomass, height and root biomass were measured. The experiment was performed with 12 plants per treatment.MM 10. Sterilized Arabidopsis seeds (Col-0) were vernalized at 4°C for 48h and germinated in 0.5MS soft agar media + 50 pM of one of the compounds of the invention (le), (Ig), (Ih), (li) and (Ij). Hypocotyl length was measured after 6 days at28°C light intensity around 120 pmoles / m2 / s and 60% relative humidity.

[0178] MM 11. Sterilized tomato commercial variety " Marmande" were germinated at 24°C for germination and transferred to pots containing (3:1:1 turba, vermiculite, perlite). Two-week old plants were treated by fertirrigation with a 5pM solution of one of the compounds of the invention (Ih) and (li) or with water (control). Formulation containing the compound was added to the soil. After the priming treatment, plants were subjected to severe drought stress by withholding water for 11-13 days followed by re-watering for the following 2 weeks. After 15 days of recovery: biomass, height and root biomass were measured. The experiment was performed with 12 plants per treatment.

[0179] Examples

[0180] Example 1: Preparation of 1-(2,4-Dihydroxyphenyl)-2-(1-naphthyloxy)ethanone

[0181] Dry hydrogen chloride was passed into a solution of 13 mmol of 2-(1-naphthyloxy)acetonitrile (1c) in dry Toluene (32 mL) at 0 °C. A solution of 15.6 mmol of resorcinol (R=H) and ZnCh ( 6.5 mmol) in dry ether (32mL) were then added. The passage of hydrogen chloride was continued for 2 h at 0 °C and the reaction mixture was left overnight at room temperature. The liquid supernatant was decanted from the solid, water (52 mL) was added to the residue and the mixture was boiled for 1 h. After cooling down the mixture, the solid formed was filtered off and washed with water until pH 7 was reached. Solids obtained were used without further purification. Crude solid (2.70 g) was recrystallized from ethanol (28 mL) for its characterization to yield 1.60 g of light pink solid. Yield 42%; m.p. 205-210 °C. IR (cm-1): 3254, 1627, 1607, 1504, 1440, 1250, 1231, 1114.

[0182] 1H-NMR (600 MHz, DMSO-d6): 11.76 (bs, 1H, OH); 8.27 (m, 1H); 7.87 (m, 1H); 7.85 (d, J = 8.8 Hz; 1H); 7.54 (m, 2H); 7.48 (d, J = 8.2 Hz; 1H); 7.38 (t, J= 7.9 Hz; 1H); 6.88 (d, J = 7.7 Hz; 1H); 6.41 (dd, J = 8.8, 2.3 Hz; 1H); 6.34 (d, J = 2.3 H; 1H); 5.61 (s, 2H).

[0183] Example 2: 7-hydroxy-2-methyl-3-(1-naphthyloxy)-4H-chromen-4-one (Ic)

[0184] A suspension of 200 mg 1-(2,4-Dihydroxyphenyl)-2-(1-naphthyloxy)ethanone in 0.32 ml acetic anhydride and 0.38 mL triethylamine was heated at 130 °C for 3 h. After cooling down, the mixture was poured into cold water (15 mL) and product was extracted with ethyl acetate (3x25 mL). The combined organic layers were washed with a 0.1N solution of HCI (30 mL) and brine (30 mL), dried over anhydrous Na2SO4, filtrated andconcentrated under reduced pressure. The residue (274 mg) was then dissolved in ethanol (3 mL) and hydrochloric acid (0.2 mL) was added. The mixture was boiled for 1 hourv The solvent was evaporated under vacuum and the residue was crystallised from 96% ethanol to yield 7-hydroxy-2-methyl-3-(naphthalen-1-yloxy)-4H-chromen-4-one (81mg, 37% yield) as off-white solid. M.p. > 280 °C, Rf (CH2CI2: CH3OH 98:2): 0.35, IR (cm-1): 3207, 1625, 1592, 1568, 1391, 1243, 1202; 1H-NMR (600 MHz, DMSO-d6): 10.87 (bs, 1H, OH); 8.32 (m, 1H); 7.94 (m, 1H); 7.87 (d, J = 8.5 Hz; 1H); 7.59 (m, 3H); 7.30 (t, J = 7.9 Hz; 1H); 6.94 (m, 2H); 6.75 (d, J = 7.7 Hz; 1H); 2.38 (s, 3H, CH3).

[0185] Example 3: Preparation of 7-hydroxy-3-(2-naphthylsulfanyl)-4H-chromen-4-one (Id)

[0186] A suspension of 200 mg 1-(2,4-dihydroxyphenyl)-2-(naphthalen-2-ylthio)ethanone in 0.30 mLacetic anhydride and 0.36 mL of triethylamine was heated at 130 °C for 3 h. After cooling down, the dark mixture was poured into cold water (15 mL) and product was extracted with ethyl acetate (3x25 mL). The combined organic layers were washed with a 0.1 N solution of HCI (30 mL) and brine (30 mL), dried over anhydrous Na2SC>4, filtrated and concentrated under reduced pressure. The residue was then dissolved in ethanol (3 mL) and hydrochloric acid (0.2 mL) was added. The mixture was boiled for 2 hours. The precipitate formed during the reaction was collected by filtration and washed with water until pH 7 was reached. The product was recrystallised from 96% ethanol to yield 7-hydroxy-2-methyl-3-(naphthalen-2-ylthio)-4H-chromen-4-one (3d; 96 mg, 45% yield) as beige solid. M.p. > 250 °C. Rf (CH2CI2: CH3OH 98:2): 0.34 IR (cm-1): 3222, 1638, 1609, 1583, 1560, 1345, 1240. 1H-NMR (600 MHz, DMSO-d6): 10.90 (bs, 1H, OH); 7.84 (m, 2H); 7.81 (d, J = 8.7 Hz; 1H); 7.78 (d, J = 8.0 Hz; 1H); 7.66 (d, J = 1.1 Hz; 1H); 7.44 (m, 2H); 7.33 (dd, J = 8.6, 1.1 Hz; 1H); 6.93 (dd, J= 8.7, 2.2 Hz; 1H); 6.89 (d, J = 2.2 Hz; 1H); 2.69 (s, 3H, CH3).

[0187] Examples 4. General Method for the synthesis of a-aryloxy-2,4-dihydroxyacetophenones (lh, li, lj)

[0188] Dry hydrogen chloride was passed for 1h into a solution of 10.0 mmol (1.0 eq) of the corresponding substituted (2-Naphthyloxy)acetonitrile in dry Toluene (25 mL) at 0 °C. A solution of 12.0 mmol (1.2 eq) of resorcinol and freshly melted ZnCI2 (5.0 mmol; 0.5 eq) in dry ether (25 mL) were then added. The passage of hydrogen chloride was continued for an additional 2 h at 0 °C and the reaction mixture was left overnight at room temperature. The liquid supernatant was decanted from the solid, water (40 mL) was added to the residue and the mixture was boiled for 1 h. After cooling down the mixture, the solid formed was filtered off and washed with water until pH 7 was reached. Solids obtained were used without further purification unless otherwise noted.

[0189]

[0190] 5: of 7- '-3-I l-2-i i-4-one (Ih)

[0191] Following the general method of example 4, starting from 2-((7-methylnaphthalen-2-yl)oxy)acetonitrile (5 mmol) and resorcinol (6 mmol), the crude solid obtained was purified by silica flash column chromatography (Cyclohexane / ethyl acetate 8:2) to yield 1-(2,4-dihydroxyphenyl)-2-((7-methylnaphthalen-2-yl)oxy)ethenone, 420 mg (27%) of light pink solid. M.p. 213-215 °C. IR (cm-1): 3307, 1622, 1610, 1512, 1442, 1252, 1207, 1139, 1083.

[0192] 1H-NMR (600 MHz, DMSO-d6): 11.75 (s, 1H), 10.64 (s, 1H), 7.84 (d, J= 8.9 Hz, 1H), 7.77 (d, J = 8.7 Hz, 1H), 7.72 (d, J = 8.3 Hz, 1H), 7.52 (s, 1H), 7.20-7.13 (m, 3H), 6.43 (dd, J = 8.8, 2.3 Hz, 1H), 6.35 (d, J = 2.3 Hz, 1H), 5.51 (s, 2H), 2.42 (s, 3H).

[0193] To a solution of 1-(2,4-Dihydroxyphenyl)-2-((7-methylnaphthalen-2-yl)oxy)ethanone (200 mg, 0.65 mmol, 1.0 eq) in dry dimethylformide (1.5 mL), boron trifluoride diethyl etherate (0.37 mL, 2.92 mmol, 4.5 eq) was added cautiously, with stirring. A previously prepared solution of methanesulfonyl chloride (0.13 mL, 1.63 mmol, 2.5 eq) in dimethylformamide (1.5 mL) was then added and the mixture was heated at 100 °C for 2 hours. The dark mixture was cooled down to room temperature, poured slowly into cold water (20 mL) with stirring and allowed to stand overnight. The solid formed was collected by filtration, dried under vacuum and recrystallized from dichloromethane to yield 7-hydroxy-3-((7-methylnaphthalen-2-yl)oxy)-4H-chromen-4-one (Ih, 72 mg, 35% yield) as yellow solid. M.p.

[0194] 233-236 °C. Rf (CH2CI2: CH3OH 98:2): 0.32. IR (cm’1): 3255, 1636, 1593, 1508, 1383, 1244, 1209, 1196.1H-NMR (600 MHz, DMSO-d6): 10.87 (bs, 1 H), 8.65 (s, 1 H), 7.93 (d, J = 8.6 Hz, 1H), 7.83 (d, J = 8.9 Hz, 1H), 7.76 (d, J = 8.3 Hz, 1H), 7.54 (s, 1H), 7.25 (dd, J = 9.0, 2.6 Hz, 1 H), 7.20-7.23 (m, 2H), 6.99-6.94 (m, 2H), 2.40 (s, 3H).13C-NMR (151 MHz, DMSO-d6) 5 171.3, 162.9, 157.6, 155.7, 150.0, 138.8, 135.8, 134.0, 129.3, 127.6, 127.4, 127.0, 126.4, 125.8, 117.1, 116.7, 115.3, 108.8, 102.5, 21.3.

[0195] Example 6: Preparation of 3-[(6-chloro-2-naphthyl)oxy]-7-hydroxy-chromen-4-one (li)

[0196] Obtained following the general method of example 4, starting from 2-((6-chloronaphthalen-2-yl)oxy)acetonitrile (4.2 mmol) and resorcinol (5 mmol). The crude solid was recrystallized from methanol (6 mL) to yield 413 mg (30%) of pure compound (1-(2,4-Dihydroxyphenyl)-2-((6-chloronaphthalen-2-yl)oxy)ethanone) as off-white solid. M.p. 201-204 °C. IR (cm-1): 3631, 3213, 1638, 1612, 1592, 1501, 1443, 1325, 1204, 1175. 1H-NMR (600 MHz, DMSO-d6): 11.70 (s, 1 H), 10.63 (s, 1 H), 7.96 (d, J = 1.3 Hz, 1 H), 7.85 (d, J = 8.9 Hz, 1 H), 7.82 (d, J= 8.9 Hz, 1H), 7.80 (d, J= 8.8 Hz, 1H), 7.44 (dd, J= 8.8, 1.9 Hz, 1H), 7.34 (d, J= 1.9 Hz, 1H), 7.31 (dd, J= 8.9, 2.3 Hz, 1H), 6.42 (dd, J= 8.8, 2.0 Hz, 1H), 6.35 (d, J= 2.0 Hz, 1H), 5.54 (s, 2H).To a solution of 1-(2,4-Dihydroxyphenyl)-2-((6-chloronaphthalen-2-yl)oxy)ethanone (400 mg, 1.22 mmol, 1.0 eq) in dry dimethylformide (3.0 mL), boron trifluoride diethyl etherate (0.69 mL, 5.48 mmol, 4.5 eq) was added cautiously, with stirring. A previously prepared solution of methanesulfonyl chloride (0.24 mL, 3.04 mmol, 2.5 eq) in dimethylformamide (3.0 mL) was then added and the mixture was heated at 100 °C for 2 hours. The dark mixture was cooled down to room temperature, poured slowly into cold water (50 mL) with stirring and allowed to stand overnight. The crude solid collected by filtration was recrystallized from ethanol to yield 3-((6-chloronaphthalen-2-yl)oxy)-7-hydroxy-4H-chromen-4-one (li, 78 mg, 19% yield) as brown solid. M.p. > 250 °C. Rf (CH2CI2: CH3OH 98:2): 0.35 IR (cm-1): 3173, 1628, 1595, 1574, 1453, 1261, 1247, 1200, 1096.1H-NMR (600 MHz, DMSO-d6): 5 10.92 (s, 1H), 8.69 (s, 1H), 8.01 (s, 1H), 7.93 (d, J= 8.5 Hz, 1H), 7.91 (d, J= 8.9 Hz, 1H), 7.82 (d, J = 8.9 Hz, 1H), 7.45 (d, J= 9.0 Hz, 1H), 7.42 (d, J = 9.0 Hz, 1H), 7.38 (s, 1H), 7.00-6.94 (m, 2H).13C NMR (151 MHz, DMSO-d6) 5 171.2, 162.9, 157.6, 156.0, 150.2, 138.6, 132.3, 129.9, 129.0,129.0, 128.6, 127.0, 127.0, 126.2, 119.0, 117.1, 115.3, 109.4, 102.5.

[0197] Example 7: Preparation of 7-hvdroxy-3-f(1-nitro-2-naphthyl)oxy1chromen-4-one (lj)

[0198] Obtained following the general method of example 4, starting from 2-((1-nitronaphthalen-2-yl)oxy)acetonitrile (7.0 mmol) and resorcinol (8.4 mmol). Crude solid was recrystallized from a 3:1 mixture of ethanol / water (120 mL) to yield 1-(2,4-Dihydroxyphenyl)-2-((1-nitronaphthalen-2-yl)oxy)ethanone, 410 mg (17%) of light yellow solid. M.p. 228-230 °C. IR (cm-1): 3300, 1626, 1613, 1522, 1509, 1360, 1336, 1243, 1094.1H-NMR (600 MHz, DMSO-d6): 11.45 (s, 1H), 10.61 (s, 1H), 8.12 (d, J= 9.2 Hz, 1H), 8.03 (d, J= 8.2 Hz, 1H), 7.73 (d, J= 8.8 Hz, 1H), 7.69 (ddd, J= 8.3, 6.9, 1.3 Hz, 1H), 7.59 (d, J= 8.7 Hz, 1H), 7.57-7.49 (m, 2H), 6.41 (dd, J = 8.8, 2.0 Hz, 1 H), 6.35 (d, J = 2.0 Hz, 1 H), 5.76 (s, 2H).

[0199] To a solution of 1-(2,4-Dihydroxyphenyl)-2-((1-nitronaphthalen-2-yl)oxy)ethanone (230 mg, 0.68 mmol, 1.0 eq) in dry dimethylformide (1.5 mL), boron trifluoride diethyl etherate (0.38 mL, 3.05 mmol, 4.5 eq) was added cautiously, with stirring. A previously prepared solution of methanesulfonyl chloride (0.13 mL, 1.70 mmol, 2.5 eq) in dimethylformamide (1.5 mL) was then added and the mixture was heated at 100 °C for 2 hours. The dark mixture was cooled down to room temperature, poured slowly into cold water (20 mL) with stirring and allowed to stand overnight. The solid formed was collected by filtration, dried under vacuum and recrystallized from 96% ethanol to yield 7-hydroxy-3-((1-nitronaphthalen-2-yl)oxy)-4Hchromen-4-one (lj, 142 mg, 60% yield) as brown solid. M.p. 251-255 °C. Rf (CH2CI2: CH3OH 98:2): 0.36. IR (cm-1): 3078, 1642, 1603, 1569, 1520, 1451, 1356, 1251, 1203, 1099.1H-NMR (600 MHz, DMSO-d6): 10.98 (s, 1H), 8.80 (s, 1H), 8.11 (d, J= 9.2 Hz,1 H), 8.08 (d, J= 8.2 Hz, 1H), 7.91 (d, J= 8.5 Hz, 1H), 7.75 (ddd, J = 9.0, 6.9, 0.6 Hz, 1H), 7.71 (d, J= 8.5 Hz, 1H), 7.61(ddd, J= 8.3, 6.8, 0.6 Hz, 1H), 7.45 (d, J= 9.2 Hz, 1H), 7.00-6.96 (m, 2H).13C NMR (151 MHz, DMSO-d6) 5 170.7, 163.1, 157.7, 150.3, 146.6, 138.0, 134.8, 132.5, 129.7, 128.9, 128.5, 126.9, 126.0, 124.6, 120.0, 116.8, 115.7, 115.5, 102.6.

[0200] Example 8: Treatment with compounds of the invention tested on Arabidopsis seedlings promoted growth under heat stress.

[0201] Compounds (la), (lb), and (Ic) of the invention were tested on wild type (WT) Arabidopsis seedlings. Plants were cultivated for a period of six days on solid media, with the media supplemented with 5 pM of one of the compounds of the invention (la), (lb), and (Ic). Two different temperature conditions were tested: 22 °C as a control (optimal) and 28 °C to simulate elevated suboptimal temperatures (Rivero, L., et al., “Handling Arabidopsis plants: growth, preservation of seeds, transformation, and genetic crosses”, Methods Mol Biol., 2014, vol.1062, pp. 3-25). The results showed that this compound has a protective effect against the adverse effects of high-temperature exposure without compromising overall growth. In a WT background, treatment with the given compound of the invention promotes growth rate of the hypocotyl compared to growing in media without addition of the compound. There is an increase of the hypocotyl length of 22%, 19% and 16% for (la), (lb), and (Ic), respectively, compared to the untreated seedlings (FIG. 2). Six-day-old seedlings of WT plants were treated with 5 pM of compound (la) or without treatment (control), growing under normal 22°C or heat shock 28°C conditions. Data was retrieved from three independent biological replicates (n > 60), following the methods described in MM.1.

[0202] Example 9: Sorghum cereal treated by seed immersion with compounds of the invention showed enhanced seedling development and growth.

[0203] The impact of compound (la) on germination rate and seedling growth was assessed in sorghum seeds as cereal model following the methods described in MM.2. Four-day-old seedlings of sorghum were germinated in water (control) or supplemented with 0.5 pM of compound (la). Sorghum seeds germinated in water supplemented with 0.5pM of the compound exhibited notable acceleration in seedling development during a period of 4 days leading to an increase in overall seedlings growth (FIG. 3). The phenotype of root length revealed a significant effect on root growth. Compound (la) exhibited a remarkable performance in growth rate of root development compared to the control, inducing a notable increase in root length compared to the control (FIG. 4). Data were retrieved from three independent biological replicates (n > 60). The incubation of seeds with compound (la) did not show any indications of toxicity on seedling development. In addition, thecompound demonstrated a beneficial effect by significantly promoting seedling development and fostering a notable root growth rate in sorghum. In summary, this study underscores the non-toxic and high beneficial impact of these compounds on seedling development in sorghum.

[0204] Example 10: Seed coating with compound (la) showed enhanced germination rate and seedling growth in tomato (Solanum lycopersicum).

[0205] The effect of the given compound of the invention, (la), (lb), and (Ic), on germination rate and seedling development was also assayed for tomato as an important agronomic crop model. The experimental assays were performed with four replicas following the methods described in MM.3. The results revealed that tomato seeds, when germinated in water supplemented with 0.5 pM of one of the compounds of the invention (la), (lb), and (Ic), over a 5-day period, exhibited enhanced seed germination rates, accelerated seedling growth, and increased root development compared to the control group (water). Under non-stress conditions, root length measurements of commercial tomato “Marmande” after 5 days germination demonstrated an increase in root development with the tested compound compared to the control (FIG. 5). Data were retrieved from four independent biological replicates (n > 80). Boxplots represent the median and interquartile range (IQR). Collectively, these findings suggest that the germination of tomato seeds with treatments of compound (la) had no adverse effects on this plant species and instead promoted overall seedling growth.

[0206] Example 11: Seed coating with compound (la) provides protection against osmotic stress in sorghum seedlings.

[0207] To determine the role of compound (la) in the response to drought stress, an analysis of overall seedling growth rate and primary root growth was conducted in sorghum seedlings following the methods described in MM.4. Sorghum seedlings that were germinated in the presence of 0.5pM of compound (la) or not treated (control) were subjected to osmotic stress by transferring them to liquid media containing sorbitol. Subsequently, the level of inhibition in both shoots and roots growth in sorbitol relative to control conditions (in water, under no osmotic stress) was quantified. Results showed that sorghum seeds when germinated in the presence of 0.5pM of compound (la) exhibited enhanced overall growth under stress conditions. These seedlings displayed longer roots and shoots compared to the control (with no treatment) (FIG. 6). A significantly lower level of inhibition in shoots growth under osmotic stress was observed in pre-treated seedlings with compounds in contrast to the non-treated seedlings. In addition to the protection effect against osmotic stress, in control conditions, the compound promoted shoots and roots growth byincreasing 42% shoots growth. Boxplots in FIG. 6 depict the distribution of 7-day-old shoots lengths in water (plain colour filling) or sorbitol (dotted filling), both for seedlings treated with compound (la) or non-treated seedlings (control). Data was retrieved from 3 independent biological replicates (n >60). Boxplots represent the median and interquartile range (IQR).

[0208] Example 12: Treatment with compounds (la), (lb), and (Ic) promote root length in Arabidopsis seedlings under osmotic stress.

[0209] To determine the role of the compounds of the invention (la), (lb), and (Ic) in the response to osmotic stress, an analysis of was conducted in Arabidopsis seedlings following the methods described in MM.5. Arabidopsis seedlings were subjected to osmotic stress by transferring them to three separate sorbitol-containing media containing one of the compounds of the invention (la), (lb), and (Ic), and another sorbitol-containing media without treatment (WT). The level of inhibition in roots growth in sorbitol was quantified after 4 days. Results showed that seedlings in the presence of compounds exhibited a lower level of root growth inhibition mediated by osmotic stress compared to the untreated seedlings (FIG. 7 and FIG. 8). These seedlings displayed longer roots compared to the control (with no treatment). A significantly lower level of inhibition in shoots growth under osmotic stress was observed in pre-treated seedlings with compounds in contrast to the non-treated seedlings. Compounds promote shoots and roots growth by increasing 30% root growth for compound (la), 66.7% increase for compound (lb), and 36.7% for (Ic), when compared to the WT in sorbitol conditions. Boxplots in FIG. 8 depict the distribution of 7-day-old root lengths in untreated media (solid border) or sorbitol (dotted border) conditions. The trendline depicts relative root growth inhibition upon stress (ratio sorbitol / control). Different letters represent significant differences (p-value < 0.05). Data from 2 independent biological replicates (n > 30).

[0210] Example 13: Foliar application of compounds of the invention to commercial tomato mature plants confers drought stress protection.

[0211] The protection effect provided by compound (la), (lb), and (Ic) in abiotic stress was determined in tomato as a crop model. A drought assay was performed in the commercial cultivar of tomato cv. " Marmande" in an early vegetative stage following the methods described in MM.6. Foliar treatment with 2pM of compound (la), (lb), and (Ic) was provided to vegetative developmental stage of tomato plants (two-week-old) in two consecutive treatment days. Plants were grown with a period of 15 days without irrigation and physiological parameters were followed during this period and the recovery phase (rewater). Results show that foliar treatment in two-week-old tomato plants enhance thecapacity of plant survival up to 100% for (lb) after a severe drought compared to the control (non-treatment) (FIG. 9 and 10). The time course of photosynthesis parameters (Fv / Fm) at the beginning (day 1) and at half of the stress period (day 6), indicated that the treated plants were healthier (FIG. 11), reaching higher photosynthesis levels during the stress period (FIG. 12, where boxplots represent the median and interquartile range (IQR) and different letters represent significant differences (p-value < 0.05)). The results indicate that the protective effect of the compounds of the invention (la), (lb) and (Ic) towards a two-week period of severe drought can be extended to crops such as tomato with spray application in a vegetative stage. Data were retrieved from 3 independent biological replicates (n > 40).

[0212] Example 14: Drought stress protection in wheat mature plants by foliar application of compound (la)

[0213] The drought protection effect of compound (la) was also evaluated in commercial wheat plants cv. “Tocayo”, following the method described in MM.7.

[0214] An adaptation to drought stress may be seen, for instance, as a change in biomass production, such as seed production, grain size and / or root length, which not only denotes resistance to the abiotic stress but moreover an increase in growth and development of the plant. After foliar treatment of two-week-old wheat plants with 2 pM of compound (la), the plants were exposed to drought for a period of 2 weeks. Treated and non-treated plants survived the stress period. However, a significant biomass production was observed for the plants that were subjected to treatment, with a higher number of tillers after 15 days without water (FIG. 13 and 14) and a significant high seed production and grain size (FIG. 15 and 16) after recovery of drought period.

[0215] Overall, results shows that plants treated by foliar spray with 2 pM of compound (la) enhance the capacity of plant growth and seed production under severe stress (20 days without water) compared to the control. Data were retrieved from 3 independent biological replicates (n > 30).

[0216] Example 15: Osmoprotectant metabolites’ induction in Arabidopsis seedlings primed by compounds of the invention.

[0217] To investigate if the compounds of the present invention induce osmoprotectant metabolites, wild type Arabidopsis seedlings were incubated with 50 pM of compound (la) for a period of 4 days and were then compared to non-treated (WT control) seedlings. Differentially secondary metabolites, such as osmoprotectant metabolites, were detected for treated seedlings with compound (la) (FIG. 16).Example 16: Foliar application of compound (la) of the invention to commercial vineyards in a field trial induce flowering and fruit set

[0218] A field trial was performed in vineyard as in MM8. Application of compound (la) to grapevine (Vitis vinifera) improves fruit set and number of grape clusters compared to the untreated (control) (FIGs. 17 and 18) at an early fruit developmental stage. Compound (la) promotes grape cluster development after fruit set by increasing grape clusters weight (FIGs. 19, 20) at 60 days after treatment.

[0219] Example 17: Foliar application of compounds (Id) of the invention to commercial tomato mature plants confers drought stress protection.

[0220] The protection effect provided by compound (Id) in abiotic stress was determined in tomato as a crop model. A drought assay was performed in the commercial cultivar of tomato cv. " Marmande" in an early vegetative stage following the methods described in MM.6. Foliar treatment with 2pM of compound (Id) was provided to vegetative developmental stage of tomato plants (two-week-old) in two consecutive treatment days. Plants were grown with a period of 15 days without irrigation and physiological parameters were followed during this period and the recovery phase (re-water).

[0221] Results show that foliar treatment in two-week-old tomato plants enhance the capacity of plant survival up to 86% for (Id) after a severe drought compared to the control (nontreatment) (FIG. 21 and 22). Data were retrieved from 3 independent biological replicates (n >40).

[0222] Example 18: Fertirrigation application of compounds of the invention to commercial tomato mature plants confers drought stress protection.

[0223] The protection effect provided by compound (le), (If), and (Ig) in abiotic stress was determined in tomato as a crop model. A drought assay was performed in the commercial cultivar of tomato cv. " Marmande" in an early vegetative stage following the methods described in MM 9. Fertirrigation treatment with compound (le), (If), and (Ig) was provided to vegetative developmental stage of tomato plants (two-week-old). Plants were grown with a period of 12 days without irrigation and physiological parameters were followed during this period and the recovery phase (re-water). Results show that treatment provide a protective effect of the compounds of the invention (le), (If) and (Ig) towards a two-week period of severe drought in crops such as tomato with only one application at vegetative stage (FIG 23)In terms of biomass production, treated plants with compounds increased biomass production up to 3X in root biomass for compound (le) and up to 2X in aerial biomass for compound (Ig) (FIG. 24A and B). Treated plants reached up to 2X in plant height for compound (Ig) compared to the non-treated tomato plants during the recovery periods (FIG. 25). Altogether, the results indicate that the protective effect of the compounds to protect plants from a period of severe drought which can be extended to crops such as tomato with application as primming in vegetative stage. Data were retrieved from 3 independent biological replicates (n > 40).

[0224] Example 19: Treatment with compounds of the invention tested on Arabidopsis seedlings promoted growth under heat stress.

[0225] Compounds (le), (Ig), (Ih), (li) and (Ij) of the invention were tested on wild type (WT) Arabidopsis seedlings. Plants were cultivated for a period of six days on solid media with the media supplemented with 50 pM of one of the compounds of the invention (le), (Ig), (Ih), (li) and (Ij). Plants were exposed to 28 °C to simulate elevated suboptimal temperatures (Rivero, L., et al). The results showed that the compounds have a protective effect against the adverse effects of high-temperature exposure. The treatment with the given compound of the invention promotes growth rate of the hypocotyl compared to growing in media without addition of the compound. There is an increase of the hypocotyl length in a range of 17% up to 49% compared to the untreated seedlings (FIG.26-27). Data was retrieved from two independent biological replicates (n > 180), following the methods described in MM.10.

[0226] Example 20: Fertirrigation application of compounds of the invention to commercial tomato mature plants confers drought stress protection.

[0227] The protection effect provided by compound (Ih) and (li) in abiotic stress was determined in tomato as a crop model. A drought assay was performed in the commercial cultivar of tomato cv. " Marmande" in an early vegetative stage following the methods described in MM. A. Fertirrigation treatment with compound (Ih) and (li) was provided to vegetative developmental stage of tomato plants (two-week-old). Plants were grown with a period of 12 days without irrigation and physiological parameters were followed during this period and the recovery phase (re-water). Results show that treatment provide a protective effect of the compounds of the invention (Ih) and (li) towards a two-week period of severe drought in crops such as tomato with only one application at vegetative stage (FIG. 28).

[0228] In terms of biomass production, treated plants with compounds increased aerial biomass production by 2X for compound (Ih) and 1,6X for compound (li) (FIG. 29A) and up to 2X for root biomass (FIG. 29B). Treated plants increased height in 33% for compound (Ih) and in22% for compound (li) compared to the non-treated tomato plants during the recovery periods (FIG. 30). Altogether, the results indicate that the protective effect of the compounds to protect plants from a period of severe drought which can be extended to crops such as tomato with application as primming in vegetative stage.

[0229] Citation List

[0230] Patent Literature

[0231] - WO2015177215A1

[0232] - WO2022253967A2

[0233] - US20090163545A1

[0234] Non-Patent Literature

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[0244] Rivero, L., etal., “Handling Arabidopsis plants: growth, preservation of seeds, transformation, and genetic crosses”, Methods Mol Biol., 2014, vol.1062, pp. 3-25.

Claims

Claims1. Use of a compound of formula (I) or an agriculturally acceptable salt thereof, either for promoting growth, yield, flowering, fruit set, or a combination of any of them of a plant at any development stage; or for protect plants against abiotic and biotic stresses at any developmental stage; in all cases as compared to the non-treated plant of the same species and at the same developmental stage,(I)wherein:Ri, R12, and R13 are radicals independently selected from H, halogen, OR14, NR14R15, SR14, (Ci-C4)-alkyl, and (Ci-C4)-alkoxy;X is a biradical or a triradical selected from O, S, and NRie;the atom joined to the naphthalene is joined to any of the carbons to which R12 and R13 are attached, and the corresponding radical of this carbon is absent, andR2-R11 are radicals independently selected from H, halogen, OH, NH2, NO2, SH, (Ci-Ce)-alkyl, O-(Ci-Ce)-alkyl, NH-(Ci-Ce)-alkyl, S-(Ci-Ce)-alkyl, (C3-C6)-cycloalkyl, phenyl, -(C1-C3)-alkyl-NHRi6, -(Ci-Csj-alkyl-COH, -(Ci-C3)-alkyl-CO-(Ci-C3)-alkyl and chlorophenyl; R14 and R15 are radicals independently selected from H, (Ci-Ce)-alkyl, (C3-C6)-cycloalkyl, phenyl, and chlorophenyl; andR16 is selected from the group consisting of H, (Ci-Ce)-alkyl, and (C3-C6)-cycloalkyl.

2. Use according to claim 1, wherein X is O, and the compounds of formula (I) has the formula (I’):DKg(I’)wherein: R1-R12 have the same meaning as in formula (I).

3. Use according to claim 2, wherein in OR14, NR14R15, and SR14, Ri4is H.

4. Use according to any of the claims 1-3, wherein in compound of formula (I) R3 is OH.

5. Use according to any of the claims 1-4, wherein the plant is a plant subject to an abiotic stress, and the use further comprises an increase in the adaptability of the plant to an abiotic stress.

6. Use according to claim 5, wherein the abiotic stress is selected from the group consisting of heat stress, drought stress, cold stress, osmotic stress and floods.

7. Use according to claim 5, wherein the plant is a plant subject to a biotic stress, and the use further comprises an increase in the adaptability of the plant to a biotic stress.

8. Use according to any of the claims 1-7, wherein the compound of formula (I) is applied to a mature plant by foliar application.

9. Use according to any of the claims 1-7, wherein the compound of formula (I) is applied to a seed or seedling by immersion, coating, incubation and / or supplementation.

10. Use according to any of the claims 1-9, wherein the plant family is selected from Brassicaceae, Poaceae, and Solanaceae.

11. Use according to claim 10, wherein the plant genus is selected from Arabidopsis, Solanum, Triticum, Sorghum, Vitis, and Cucurbitaceae.

12. A compound of formula (h) or an agriculturally acceptable salt thereof,(h)wherein:Ri’, R11’ and R12’ are radicals independently selected from H, halogen, OR14, NR14R15, SH, (C2-C4)-alkyl, and (Ci-C4)-alkoxy;X is a biradical or a triradical selected from O, S, and NRie;the atom joined to the naphthalene is joined to any of the carbons to which Rn’ and R12’ are attached, and the corresponding radical of this carbon is absent, and R2-Rio are radicals independently selected from H, halogen, OH, NH2, NO2, SH, (Ci-Ce)-alkyl, O-(Ci-Ce)-alkyl, NH-(Ci-Ce)-alkyl, S-(Ci-Ce)-alkyl, (C3-C6)-cycloalkyl, phenyl, -(Ci-Csj-alkyl-NHR16, -(Ci-Csj-alkyl-COH, -(Ci-C3)-alkyl-CO-(Ci-C3)-alkyl and chlorophenyl,R14-R15 are radicals independently selected from H, (Ci-Ce)-alkyl, (C3-C6)-cycloalkyl, phenyl, and chlorophenyl;R16 is selected from the group consisting of H, (Ci-Ce)-alkyl, and (C3-C6)-cycloalkyl; and with the proviso that compound of formula (h) is other than:7-hydroxy-3-(2-naphthyloxy)-4H-chromen-4-one;7-hydroxy-2-methyl-3-(2-naphthyloxy)-4H-chromen-4-one, and7-hydroxy-3-(1-naphthyloxy)-4H-chromen-4-one.

13. The compound according to claim 12, wherein in OR14, NR14R15, and SR14, R14 is H and the compounds of formula (h) has the formula (h’), wherein R1-R12 have the same meaning as in formula (h).

14. The compound according to claim 13, wherein:the oxygen joined to the naphthalene is joined to the carbon to which R12’ is attached, and thus R12’ is absent;R1’ and Rn’ are radicals independently selected from H or halogen; andR2’-RIO’ are radicals independently selected from H, halogen, OH, (Ci-Ce)-alkyl, O-(Ci-Ce)-alkyl, -(Ci-C3)-alkyl-NHRi6, -(Ci-C3)-alkyl-COH, and -(Ci-C3)-alkyl-CO-(Ci-C3)-alkyl.

15. An agrochemical composition comprising an effective amount of the compound of formula (h) as defined in any of the claims 12-14, together with appropriate amounts of one or more agricultural excipients or carriers; wherein the effective amount is either for promoting growth, yield, flowering, _fruit set, or a combination of any of them of a plant at any development stage; or for protect plants against abiotic and biotic stresses at any developmental stage; in all cases as compared to the non-treated plant of the same species and at the same developmental stage.

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