Plant activator

Abstract

To provide a plant activator which has low soil pollution and toxicity and has an excellent plant growth acceleration effect.SOLUTION: Provided is a plant activator comprising a hydroxy fatty acid derivative, a salt thereof, or an ester thereof as an effective ingredient, the hydroxy fatty acid having a structural formula of HOOC-(R1)-CH(OH)-CH(OH)-CH=CH-CH(OH)-R2 (I) and / or HOOC-(R1)-CH(OH)-CH=CH-CH(OH)-CH(OH)-R2 (II) (in the formula, R1 is a linear or branched hydrocarbon group having 4 to 12 carbon atoms, which may contain 1 or more double bonds and / or hydroxy groups and, when it contains a double bond(s), the position thereof is not limited; and R2 is a linear or branched hydrocarbon group having 2 to 8 carbon atoms, which may contain 1 or more double bonds and / or hydroxy groups and, when it contains a double bond(s), the position thereof is not limited).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a plant activator. [Background technology]

[0002] Since ancient times, measures such as optimizing temperature and sunlight conditions and applying fertilizer have been taken to promote plant growth. However, these measures have their limits. For example, not only can the amount of fertilizer used be increased, but it is also difficult to expect growth promotion beyond a certain level. In addition, applying too much fertilizer can actually hinder plant growth and even lead to soil contamination.

[0003] In addition to the above-mentioned measures, methods have been reported for activating plants using plant activators that have plant growth regulating effects such as growth promotion, dormancy suppression, and stress suppression. For example, Patent Document 1 describes a plant activator whose active ingredient is a ketol fatty acid having 4 to 24 carbon atoms. Patent Document 2 reports a plant activator containing fatty acid metabolites obtained by metabolizing fatty acids having 4 to 30 carbon atoms with Proteobacteria in an environment with a dissolved oxygen concentration of 0.1 to 8 mg / L. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-131006 [Patent Document 2] International Publication No. 2018 / 47918 Summary of the Invention [Problem to be solved by the invention]

[0005] There is a demand for a plant activator that has a growth-promoting effect superior to that of the plant activator containing a ketol fatty acid as an active ingredient, as described in Patent Document 1, and the plant activator described in Patent Document 2, and that has excellent uniformity and dispersibility when applied by irrigation or spraying.

[0006] An object of the present invention is to provide a plant activator which is less likely to pollute soil and is less toxic, and which has an excellent plant growth-promoting effect. [Means for solving the problem]

[0007] The present invention relates to a compound represented by the following formula (I) and / or (II): HOOC-(R 1 )-CH(OH)-CH(OH)-CH=CH-CH(OH)-R 2 (I) HOOC-(R 1 )-CH(OH)-CH=CH-CH(OH)-CH(OH)-R 2 (II) During the ceremony, R 1 represents a linear or branched hydrocarbon group having 4 to 12 carbon atoms, which may contain one or more double bonds and / or OH groups, and when a double bond is contained, the position of the double bond is not limited; R 2 represents a linear or branched hydrocarbon group having 2 to 8 carbon atoms, which may contain one or more double bonds and / or OH groups, and when a double bond is contained, the position of the double bond is not limited; The present invention relates to a plant activator characterized by containing, as an active ingredient, a hydroxylated fatty acid derivative having the structural formula: 1 is -(CH2) n - (where n is an integer of 4 to 12) is preferred.

[0008] The hydroxylated fatty acid derivative is R 1 The hydrocarbon group has 6 to 8 carbon atoms, and R 2 A plant activator that is a hydroxylated fatty acid derivative in which the hydrocarbon group has 4 to 6 carbon atoms is preferred.

[0009] The hydroxylated fatty acid derivative is R 1 But -(CH2) n -(n is an integer between 4 and 12), and R2 But C n H 2n+1 A plant activator that is a hydroxylated fatty acid derivative having the structure - (n is an integer of 2 to 8) is preferred.

[0010] The hydroxylated fatty acid derivative is R 1 is an alkylene group having 7 carbon atoms (-(CH2)7-), and R 2 However, a plant activator that is a hydroxylated fatty acid derivative having an alkyl group of 5 carbon atoms (CH3CH2CH2CH2CH2-) is preferred.

[0011] The plant activator is preferably one in which the hydroxylated fatty acid derivative is hydroxyoctadecenoic acid.

[0012] The plant activator is preferably one in which the hydroxylated fatty acid derivative is 9,10,13-trihydroxy-11-octadecenoic acid.

[0013] The plant activator is preferably one in which the hydroxylated fatty acid derivative is 9,12,13-trihydroxy-10-octadecenoic acid.

[0014] "Octadecaenoic acid" is a conventional term (e.g., JP 3-14539 A, etc.), and the above-mentioned "9,10,13-trihydroxy-11-octadecenoic acid" can also be written as "9,10,13-trihydroxyoctadec-11-enoic acid" or "9,10,13-trihydroxy-11-octadecenoic acid." Similarly, the above-mentioned "9,12,13-trihydroxy-10-octadecenoic acid" can also be written as "9,12,13-trihydroxyoctadec-10-enoic acid" or "9,12,13-trihydroxy-10-octadecenoic acid." In the examples, the manufacturer's name is also listed in parentheses. The above explanation applies to all "octadecenoic acid" used in this specification, claims, drawings, and abstract.

[0015] The structural formula of "9,10,13-trihydroxy-11-octadecenoic acid" is shown in the following structural formula (1).

[0016] [ka]

[0017] The structural formula of "9,12,13-trihydroxy-10-octadecenoic acid" is shown in the following structural formula (2).

[0018] [ka]

[0019] The plant activator is preferably a plant activator further comprising a surfactant and / or a diluent or carrier.

[0020] The plant activator preferably contains the hydroxylated fatty acid derivative or its salt or ester at a concentration of 0.05 to 5 mg / L.

[0021] The plant activator is preferably a plant activator used as a spray or dipping agent to be brought into contact with the stems, leaves or roots of plants, or as a soil drench agent.

[0022] The plant activator is preferably a plant activator used for plants selected from the Brassicaceae, Poaceae, Leguminosae, Solanaceae, Rosaceae, Amaranthaceae, Cucurbitaceae, and Malvaceae families. [Effects of the Invention]

[0023] The plant activator of the present invention is easily decomposed in the environment, so that it is less likely to pollute soil and is less toxic, and has an excellent plant growth-promoting effect. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a graph showing the growth-promoting effect on plant weight of mizuna, a Brassicaceae plant. [Figure 2]1 is a graph showing the growth-promoting effect on the leaf length of mizuna, a plant of the Brassicaceae family. [Figure 3] 1 is a graph showing the growth-promoting effect on plant weight of spinach, a plant of the Amaranthaceae family. [Figure 4] 1 is a graph showing the growth-promoting effect on the leaf length of spinach, a plant of the Amaranthaceae family. [Figure 5] 1 is a graph showing the expression level of resistance-inducing genes in tomato, a plant of the Solanaceae family. [Figure 6] 1 is a graph showing the expression level of resistance-inducing genes in cucumber, a plant of the Cucurbitaceae family. [Figure 7] 1 is a graph showing the expression level of resistance-inducing genes in Arabidopsis thaliana, a plant of the Brassicaceae family. DETAILED DESCRIPTION OF THE INVENTION

[0025] Plant activators The plant activator of the present invention is a hydroxylated fatty acid derivative, The following formula (I) and / or (II): HOOC-(R 1 )-CH(OH)-CH(OH)-CH=CH-CH(OH)-R 2 (I) HOOC-(R 1 )-CH(OH)-CH=CH-CH(OH)-CH(OH)-R 2 (II) During the ceremony, R 1 represents a linear or branched hydrocarbon group having 4 to 12 carbon atoms, which may contain one or more double bonds and / or OH groups, and when a double bond is contained, the position of the double bond is not limited; R 2 represents a linear or branched hydrocarbon group having 2 to 8 carbon atoms, which may contain one or more double bonds and / or OH groups, and when a double bond is contained, the position of the double bond is not limited; The present invention is characterized in that it contains, as an active ingredient, a hydroxylated fatty acid derivative having the structural formula represented by the following formula: 1 is -(CH2) n - (where n is an integer of 4 to 12). The present invention also relates to a plant activator containing, as an active ingredient, a compound of formula (I) and / or (II) or a salt or ester thereof, including all geometric isomers and stereoisomers.

[0026] In the present invention, "plant activation" refers to regulating plant growth activity in some way to activate or maintain it, and encompasses plant growth regulating effects such as growth promotion (a concept that includes stem and leaf expansion, promotion of tuber and root growth, etc.), dormancy suppression, induction or conferring of plant resistance to stress (e.g., disease), and anti-aging. For example, contacting a part of a plant's stem, leaf, or root with the plant activator of the present invention can impart a growth-promoting effect to the plant. Inoculation of plants with the plant activator of the present invention has been confirmed to increase leaf length and leaf weight, which are indicators of plant growth, and promote tuber or root growth, compared to untreated plants. Therefore, it is believed that the plant activator of the present invention imparts a growth-promoting effect to plants. Use of the plant activator of the present invention can promote plant growth and increase the yield of plants such as vegetables, grains, and fruits. The plant activator of the present invention has an extremely high plant growth-promoting effect, which can result in an excellent increase in the yield of commercial crops and improved harvest efficiency.

[0027] In one embodiment of the present invention, 9(S),10(S),13(S)-11(E)-trihydroxyoctadecenoic acid and / or 9(S),12(S),13(S)-10(E)-trihydroxyoctadecenoic acid and their derivatives are used as examples of hydroxylated fatty acid derivatives and are suitable as plant activators of the present invention. In this specification, hydroxylated fatty acids including hydroxyoctadecenoic acid or its derivatives, or derivatives thereof, are collectively referred to as hydroxylated fatty acid derivatives.

[0028] The salts of the hydroxylated fatty acid derivatives of the present invention are not particularly limited as long as they are one or more agriculturally acceptable salts, such as ammonium salts, alkylammonium salts such as ammonium salts and tetramethylammonium salts; alkaline earth metal salts such as calcium salts and magnesium salts; alkali metal salts such as sodium salts, lithium salts, and potassium salts; metal salts such as cobalt salts and manganese salts; and salts contained in fertilizers. For example, by converting the hydroxylated fatty acid derivatives into salts, high water solubility and / or low deliquescence can be achieved, making the hydroxylated fatty acid derivatives easier to handle. Furthermore, in the present invention, the salts of the hydroxylated fatty acid derivatives include various forms of salts of the hydroxylated fatty acid derivatives, such as salts formed between the hydroxylated fatty acid derivatives and acids or bases, hydrates thereof, and mixtures thereof.

[0029] Examples of the esters of the hydroxylated fatty acid derivatives of the present invention include, but are not limited to, methyl esters, ethyl esters, propyl esters, butyl esters, pentyl esters, isopentyl esters, octyl esters, and the like.

[0030] As described below, the plant activator containing the hydroxylated fatty acid derivative of the present invention is characterized by exhibiting a significantly superior plant growth-promoting effect on plants when applied to plants, compared with known plant growth-promoting materials. This indicates that the plant activator of the present invention has a high plant growth-promoting effect. It also indicates that application of the plant activator to plants suppresses plant diseases by expressing resistance-inducing genes in the salicylic acid pathway and the jasmonic acid pathway, which provide plants with immune mechanisms against diseases.

[0031] The plant activator of the present invention may optionally contain a compatible surfactant and / or diluent or carrier suitable for use in the plant activator. For example, the diluent may improve the dispersibility of the hydroxylated fatty acid derivative, e.g., hydroxyoctadecenoic acid or its salt or ester, in the solvent. Furthermore, surfactants such as dispersing aids and wetting agents may be included to improve the solubility and dispersibility of the hydroxylated fatty acid derivative used in the present invention in the diluent. These additional components are not particularly limited as long as they are agriculturally acceptable. Furthermore, the plant activator of the present invention may further contain, in addition to the hydroxylated fatty acid derivative or its salt or ester, other components beneficial to plants, such as components commonly used in pesticide formulations or one or more fertilizer components, other than the surfactant, diluent, and carrier.

[0032] The plant activator of the present invention may contain a hydroxylated fatty acid derivative or its salt or ester, and the origin thereof is not particularly limited. The hydroxylated fatty acid derivative, such as hydroxyoctadecenoic acid, or its salt or ester may be obtained, for example, by chemical synthesis, or may be produced using a microorganism or by the action of a microbial enzyme on a substrate such as a fatty acid. The plant activator of the present invention may contain the hydroxylated fatty acid derivative at the desired concentration. For example, when hydroxyoctadecenoic acid produced using a microorganism is used as the hydroxylated fatty acid derivative, a mixture containing hydroxyoctadecenoic acid may be used as the plant activator. When a biosurfactant secreted by a microorganism is contained in the mixture, the dispersibility of the plant activator of the present invention may be improved without the addition of the aforementioned additive components. Even if the hydroxylated fatty acid derivative itself is insoluble, it may be emulsified with a biosurfactant and dispersed in water.

[0033] The plant activator of the present invention can be applied to plants by any method. Any method is acceptable as long as it contacts the plant body, such as the roots, stems, or leaves. It may be applied directly to the plant body, or it may be applied to a cultivation support, such as soil, in which the plant body is established. For example, the plant activator of the present invention can be used as a spray or immersion agent that contacts the plant stems, leaves, or roots, or as a soil drench agent. The plant activator of the present invention may also be used as a sustained-release agent by being encapsulated in a porous structure or capsule, or by being impregnated in a sheet or the like. For storage stability, the plant activator may be powdered with an appropriate excipient by freeze-drying or spray-drying. The plant activator of the present invention imparts a plant growth-promoting effect to plants, resulting in increased yields due to increased plant body, such as increased leaf length, plant weight, leaf number, and crop weight, and improved harvest efficiency due to increased stem number per plant. It also suppresses plant diseases through the expression of resistance genes.

[0034] The plant activator of the present invention can promote plant growth and suppress disease by a simple treatment such as spraying, eliminating the need for special equipment, etc., making the present invention extremely advantageous in this respect as well. Furthermore, because hydroxyoctadecenoic acid, for example, is an oxide of a naturally occurring fatty acid, the plant activator of the present invention is excellent in that it has a low environmental impact and causes almost no phytotoxicity to the plants to which it is applied.

[0035] The application of the hydroxylated fatty acid derivative or its salt or ester, which is the active ingredient of the plant activator of the present invention, to a plant and / or cultivation support can be carried out, for example, by applying the hydroxylated fatty acid derivative or its salt or ester to the plant and / or cultivation support in the form of a liquid dissolved or dispersed in water and / or a water-soluble solvent. For example, a liquid in which the hydroxylated fatty acid derivative or its salt or ester is dissolved or dispersed can be sprayed or applied to the above-ground parts (stems, leaves, etc.) of the target plant. The plant activator of the present invention may be applied to the target plant at least once, for example, after emergence and before harvest, or may be applied multiple times.

[0036] In one embodiment of the present invention, the hydroxylated fatty acid derivative, or its salt or ester, can be used at a concentration of 500 mg / L or less. The preferred concentration of the hydroxylated fatty acid derivative, or its salt or ester, depends on the plant species and its condition, but concentrations exceeding 500 mg / L may cause phytotoxicity to the plant. There is no particular lower limit for the concentration of the hydroxylated fatty acid derivative, or its salt or ester, but 0.05 mg / L or higher is preferred. In a preferred embodiment of the present invention, the concentration of the hydroxylated fatty acid derivative, or its salt or ester, is 0.01 to 100 mg / L.

[0037] The plants to which the plant activator of the present invention can be applied are not particularly limited, and can be used effectively on plants in general, including plants of the Poaceae, Fabaceae, Solanaceae, Rosaceae, Amaranthaceae, Malvaceae, Cucurbitaceae, and Brassicaceae families. For example, the growth of Poaceae plants such as grass, rice, wheat, and corn, Leguminaceae plants such as soybean, broad bean, kidney bean, and licorice, Solanaceae plants such as tomato, eggplant, chili pepper, bell pepper, and potato, Rosaceae plants such as strawberry, Amaranthaceae plants such as spinach, Malvaceae plants such as cotton and okra, Cucurbitaceae plants such as cucumber, pumpkin, and watermelon, and Brassicaceae plants such as komatsuna and mizuna can be effectively promoted. Furthermore, the target plants to which the plant activator can be applied are not limited to wild-type plants, and may also be mutants or transformants, for example. Furthermore, the variety of each plant is not particularly limited. [Example]

[0038] The present invention will be described based on examples, but the present invention is not limited to only the examples.

[0039] Example 1 Evaluation of Mizuna Growth In Example 1, a 2:1 mixture of 9,10,13-trihydroxy-11-octadecenoic acid (manufactured by Larodan Fine Chemicals, named 9(S),10(S),13(S)-trihydroxy-11(E)-octadecenoic acid in English: 9(S),10(S),13(S)-trihydroxy-11(E)-octadecenoic acid in Japanese), 200 mg / L ethanol solution) and 9,12,13-trihydroxy-10-octadecenoic acid (manufactured by Larodan Fine Chemicals, named 9(S),12(S),13(S)-trihydroxy-10(E)-octadecenoic acid in English: 9(S),12(S),13(S)-trihydroxy-10(E)-octadecenoic acid in Japanese), 200 mg / L ethanol solution) was used as a trihydroxyoctadecenoic acid solution.

[0040] As a comparative example, a plant activator containing ketol fatty acids and fatty acid metabolites prepared by the following method was used.

[0041] Preparation of ketol fatty acids 10 mg of soybean-derived lipoxidase (Sigma-Aldrich) was added to a linoleic acid suspension consisting of 1 g of linoleic acid, 0.15 g of potassium dihydrogen phosphate, and 100 mL of distilled water, and the mixture was stirred overnight to produce lipid peroxide 1. The production of lipid peroxide 1 was confirmed by comparison with a standard substance by TLC (chloroform:ethanol = 20:1, sulfuric acid coloring) and by an increase in OD 234 nm. The major component of lipid peroxide 1 was confirmed by NMR analysis to be 13-HPODE ((9Z,11E)-13-(hydroperoxy)-9,11-octadecadienoic acid). 0.1 mg of allene oxide synthase (Sigma-Aldrich) was added to the resulting peroxide 1 and stirred overnight to produce ketol fatty acids. The enzymatic reaction was then terminated by adding dilute hydrochloric acid under ice cooling to adjust the pH of the reaction solution to 3.0. The pH was then adjusted to 6.5 to prepare an aqueous solution of ketol fatty acid (9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid, 13-KODA).

[0042] Preparation of plant activators containing fatty acid metabolites <Preculture process> 20 g of peptone (protein hydrolysate manufactured by Difco), 1.5 g of magnesium sulfate heptahydrate, and 1.5 g of dipotassium hydrogen phosphate were dissolved in 1 L of water in a glass Erlenmeyer flask, and the flask was sterilized by autoclaving at 121°C for 20 minutes. After cooling to room temperature, the flask was filled with proteobacteria (Azoarcus buckelii, Propionivibrio pelophilus, Thauera selenatis, Pandoraea pulmonicola, Pusillimonas noertemannii, Rhodovulum kholense, Haematobacter massiliensis, Hyphomicrobium hollandicum, Chelatovorus multitrophus, Nitrosococcus halophilus, Thioalkalivibrio thiocyanodenitrificans, Marinobacter hydrocarbonoclasticus, Halomonas xinjiangensis, Pseudomonas A bacterial solution of a complex flora including Bacillus subtilis, ... 8 After the cultivation, the culture medium was centrifuged at 15,000×G and 20° C. to separate the bacterial cells from the culture medium, and the bacterial cells were collected. <Fatty acid metabolic process> To 1 L of sterilized water in a glass Erlenmeyer flask, 12 g of linoleic acid (primary linoleic acid, Fujifilm Wako Pure Chemical Industries, Ltd.), 1.5 g of magnesium sulfate heptahydrate, 1.5 g of dipotassium hydrogen phosphate, and the entire amount of bacterial cells obtained in the pre-culture step were added. This mixture was cultured for 4 days using a Bioshaker® (BR-23UM, Taitec Corporation) at 20°C, 120 rpm, and a dissolved oxygen concentration of 4 mg / L. Linoleic acid degradation was confirmed by analyzing the culture solution by measuring absorbance at 230 nm using a Shimadzu BioSpec-mini spectrophotometer. The culture solution containing the bacterial cells after culture was used as the fatty acid metabolite contained in the fatty acid metabolite-containing plant activator.

[0043] The trihydroxyoctadecenoic acid solution, ketol fatty acid aqueous solution, and culture solution containing fatty acid metabolites obtained above were diluted with distilled water to a final concentration of 0.05 mg / L for trihydroxyoctadecenoic acid, ketol fatty acid, and fatty acid metabolites, respectively, to prepare treatment solutions. A 72-well cell tray was filled with culture soil (Takii Seed Co., Ltd., product name "Seed Maki Culture Soil") and sown with accelerated germination-treated mizuna seeds. After germination, the mizuna seedlings were thinned to two plants per cell. Light conditions were set at 12 hours light / 12 hours dark. Water was supplied by irrigating with tap water approximately once every four days. Nine and 12 days after sowing, each treatment solution was sprayed onto the aboveground parts of the plants using a sprayer (300 L / 10 a). The negative control ("untreated") was not sprayed with any treatment solution.

[0044] The plants were harvested 21 days after sowing, and the wet weight of the aboveground parts per plant and the length of the leaves were measured. The results are shown in Figures 1 and 2, respectively.

[0045] As shown in Figures 1 and 2, the average aboveground wet weight and leaf length of mizuna plants (n = 20) treated with hydroxyoctadecenoic acid were increased compared to the untreated control. The wet weight of aboveground shoots was 0.19 g / plant in the untreated control, while the hydroxyoctadecenoic acid-treated plants were 0.35 g / plant. Furthermore, the leaf length was 9.6 cm in the hydroxyoctadecenoic acid-treated plants, compared to 8.1 cm in the untreated control. A t-test revealed significant differences in both aboveground wet weight and leaf length in the hydroxyoctadecenoic acid-treated plants compared to the untreated control. In contrast, little increase in aboveground wet weight was observed in the plants treated with fatty acid metabolites or ketol acids. Furthermore, leaf length decreased in the ketol fatty acid-treated plants.

[0046] Example 2 Evaluation of spinach growth A 72-well cell tray was filled with culture soil (Takii Seed Co., Ltd., product name "Seed Maki Culture Soil") and sown with accelerated-germination spinach seeds. After germination, the spinach seedlings were thinned to two plants per cell. Light conditions were set at 12 hours light / 12 hours dark. Water was supplied by irrigating with an appropriate amount of tap water approximately once every three days. The treatment solution used was the hydroxyoctadecenoic acid treatment solution prepared in Example 1, and 16 days after sowing, the treatment solution was sprayed onto the above-ground parts of the plants (300 L / 10 a) using a sprayer, as a foliar application. No treatment solution was sprayed on the negative control ("untreated group").

[0047] The plants were harvested 23 days after sowing, and the wet weight of the aboveground parts and leaf length per plant were measured. The results are shown in Figures 3 and 4, respectively.

[0048] As shown in Figures 3 and 4, the average aboveground wet weight and leaf length of spinach plants (n = 46) treated with hydroxyoctadecenoic acid were both increased compared to the untreated control. The wet weight of aboveground shoots was 0.20 g / plant in the untreated control, while it was 0.26 g / plant in the hydroxyoctadecenoic acid-treated control. Furthermore, the leaf length was 5.2 cm in the untreated control, while it was 5.7 cm in the hydroxyoctadecenoic acid-treated control. A t-test revealed significant differences in both aboveground wet weight and leaf length in the hydroxyoctadecenoic acid-treated control.

[0049] 1 to 4, an increase in the wet weight of the above-ground parts and an increase in leaf length were confirmed for mizuna, a plant of the Brassicaceae family, and spinach, a plant of the Amaranthaceae family. This shows that the plant activator of the present invention has an excellent growth-promoting effect on plants.

[0050] Example 3 Evaluation of resistance induction in tomato Distilled water was added to the trihydroxyoctadecenoic acid (trihydroxyoctadecenoic acid) solution (ethanol solution of a mixture of 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid) prepared in the first part of Example 1 to prepare diluted solutions with final trihydroxyoctadecenoic acid concentrations of 5 mg / L (5 ppm) and 50 mg / L (50 ppm), respectively, to prepare two types of treatment solutions.

[0051] Tomato seedlings (variety: CF House Momotaro; purchased from Ibigawa Kogyo Co., Ltd.) at the two-leaf stage were transplanted into 9 cm pots filled with soil (Takii Seed Co., Ltd., product name "Seed Planting Soil"). The temperature was kept constant at 30°C, and the light conditions were set at 12 hours light / 12 hours dark using fluorescent lights. Water was supplied by irrigating with an appropriate amount of tap water approximately once a day. 24 hours after transplanting, the treatment solution of the two types of hydroxyoctadecenoic acid prepared above was sprayed onto the above-ground parts of the plants using a sprayer (10 mL / plant) as a foliar spray. Distilled water was sprayed as a negative control ("untreated group").

[0052] Forty-eight hours after foliar application, RNA was extracted from the true leaves of treated tomatoes and untreated control tomatoes using a commercially available RNA extraction kit (GPR1002, Viogene). cDNA was prepared from the RNA, and the expression levels of the resistance genes PR-1b, PR-2a, PR-2b, PR-3a, PR-3b, and PR-5 were analyzed by real-time PCR. Gene expression levels were normalized to those of housekeeping genes. Three tomato seedlings were tested for each treatment, and the average expression levels obtained are shown in Figure 5. The types of resistance genes measured were based on the Japanese Journal of Plant Pathology, Vol. 83, pp. 3–9, 2017. PR-1b, PR-2a, PR-3a, and PR-5 are resistance genes in the salicylic acid pathway, while PR-2b and PR-3b are resistance genes in the jasmonic acid pathway.

[0053] Example 4 Evaluation of resistance induction in cucumber Distilled water was added to the trihydroxyoctadecenoic acid (trihydroxyoctadecenoic acid) solution (ethanol solution of a mixture of 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid) prepared in the first part of Example 1 so that the final concentration of trihydroxyoctadecenoic acid was 50 mg / L (50 ppm), to prepare a diluted solution, which was used as the treatment solution.

[0054] Cucumber seedlings (variety: Hokushin; purchased from Ibigawa Kogyo Co., Ltd.) at the two-leaf stage were transplanted into 9 cm pots filled with soil (Takii Seed Co., Ltd., product name "Seed Planting Soil"). The temperature was kept constant at 25°C, and the light conditions were set at 12 hours light / 12 hours dark using fluorescent lights. Water was supplied by irrigating with an appropriate amount of tap water approximately once a day. Five days after transplanting, the treatment solution of hydroxyoctadecenoic acid prepared above was sprayed onto the above-ground parts of the plants using a sprayer (10 mL / plant) as a foliar spray. Distilled water was sprayed as a negative control ("untreated group").

[0055] Seventy-two hours after foliar spray, the expression levels of the resistance genes PR-8 and POX were examined in cucumbers treated with the treatment solution and untreated cucumbers as controls, using the same procedures as in Example 3. Three cucumber seedlings were tested for each treatment group, and the average expression levels obtained are shown in Figure 6. The types of resistance genes measured were determined based on the results in Journal of Plant Molecular Breeding, 2016, Vol. 4, No. 2, pp. 33-40 and Sono Gakuken, 2011, Vol. 10, No. 3, pp. 429-433. PR-8 and POX are resistance genes in the salicylic acid pathway.

[0056] Example 5 Evaluation of resistance induction in Arabidopsis thaliana Dilutions were prepared by adding distilled water to the trihydroxyoctadecenoic acid (trihydroxyoctadecenoic acid) solution (ethanol solution of a mixture of 9,10,13-trihydroxy-11-octadecenoic acid and 9,12,13-trihydroxy-10-octadecenoic acid) prepared in the first part of Example 1 so that the final concentrations of trihydroxyoctadecenoic acid were 4 mg / L (4 ppm) and 40 mg / L (40 ppm), respectively, to prepare two types of treatment solutions.

[0057] Arabidopsis seeds (Col-0; purchased from Inplanta Innovations, Inc.) were grown at one seed per 1cm on a 3cm x 3cm x 3cm rockwool medium (Rockwool Block 60P, manufactured by Yamato Plastic Co., Ltd.). 2 The seeds were sown at a cultivation density of 1000. The temperature was kept constant at 22°C, and the light conditions were set at 12 hours light / 12 hours dark using fluorescent lamps. For 15 days after sowing, the rock wool was immersed in a culture solution prepared by diluting commercially available liquid fertilizer (Sumitomo Chemical Gardening Co., Ltd., Vegeful liquid fertilizer) 1000 times, and the plants were grown hydroponically. After 15 days, 13 mL of the treatment solution containing the two types of hydroxyoctadecenoic acid prepared above was added to the rock wool, and the plant was left to stand for 5 hours, after which the original culture solution was replaced and the plants were allowed to continue growing. The negative control was left without any treatment solution ("untreated group").

[0058] Twenty-four hours after treatment, the expression levels of the resistance genes PR-1, PR-2, and PDF1.2 were measured in Arabidopsis plants treated with each treatment solution and untreated control plants using the same procedures as in Example 3. Three Arabidopsis seedlings were tested for each treatment group, and the average expression levels obtained are shown in Figure 7. The types of resistance genes measured were determined based on PLoS ONE, Vol. 9, No. 1, e86882. PR-1 and PR-2 are resistance genes in the salicylic acid pathway, and PDF1.2 is a resistance gene in the jasmonic acid pathway.

[0059] As can be seen from Figure 5 (Example 3), Figure 6 (Example 4), and Figure 7 (Example 5), an increase in the expression level of the resistance gene was confirmed in tomato (Solanaceae), cucumber (Cucurbitaceae), and Arabidopsis (Brassicaceae). This shows that the plant activator of the present invention has an excellent disease suppression effect on plants.

[0060] From the above results, it can be seen that the plant activator of the present invention is an excellent plant activator that has low soil contamination and toxicity, can promote plant growth, and can also suppress plant diseases by expressing resistance genes.

Claims

1. Formula (I) and / or (II) below: P.S. 1 )-CH(OH)-CH(OH)-CH=CH-CH(OH)-R 2 (I) P.S. 1 )-CH(OH)-CH=CH-CH(OH)-CH(OH)-R 2 (II) During the ceremony, R 1 represents a linear or branched hydrocarbon group having 4 to 12 carbon atoms, which may contain one or more double bonds and / or OH groups, and when a double bond is contained, the position of the double bond is not limited; R 2 represents a linear or branched hydrocarbon group having 2 to 8 carbon atoms, which may contain one or more double bonds and / or OH groups, and when a double bond is contained, the position of the double bond is not limited; A plant activator characterized by comprising as an active ingredient a hydroxylated fatty acid derivative having the structural formula:

2. The plant activator according to claim 1, wherein the hydroxylated fatty acid derivative: R 1 wherein the hydrocarbon group has 6 to 8 carbon atoms; R 2 The hydrocarbon group has 4 to 6 carbon atoms.

3. The plant activator according to claim 1, wherein the hydroxylated fatty acid derivative: R 1 But -(CH 2 ) n -(n is an integer from 4 to 12), R 2 But C n H 2n+1 -(n is an integer of 2 to 8).

4. The plant activator according to claim 3, wherein the hydroxylated fatty acid derivative: R 1 is an alkylene group having 7 carbon atoms (-(CH 2 ) 7 -) and R 2 is an alkyl group having 5 carbon atoms (CH 3 CH 2 CH 2 CH 2 CH 2 -).

5. 5. The plant activator according to claim 4, wherein the hydroxylated fatty acid derivative is hydroxyoctadecenoic acid.

6. 6. The plant activator according to claim 5, wherein the hydroxylated fatty acid derivative is 9,10,13-trihydroxy-11-octadecenoic acid (9,10,13-trihydroxy-11-octadecenoic acid).

7. 6. The plant activator according to claim 5, wherein the hydroxylated fatty acid derivative is 9,12,13-trihydroxy-10-octadecenoic acid (9,12,13-trihydroxy-10-octadecenoic acid).

8. The plant activator according to any one of claims 1 to 7, further comprising a surfactant and / or a diluent or carrier.

9. 9. The plant activator according to claim 1, wherein the concentration of the hydroxylated fatty acid derivative or its salt or ester is 0.05 to 5 mg / L.

10. The plant activator according to any one of claims 1 to 9, which is used as a spray or dipping agent to be brought into contact with the stems, leaves or roots of plants, or as a soil drench agent.

11. The plant activator according to any one of claims 1 to 10, which is used for a plant selected from the Brassicaceae, Poaceae, Leguminosae, Solanaceae, Rosaceae, Amaranthaceae, Cucurbitaceae, and Malvaceae families.

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