Application of 4-hydroxycinnamyl aldehyde in prevention and treatment of plant fungal diseases

Abstract

The invention belongs to the technical field of plant protection, discloses application of 4-hydroxycinnamyl aldehyde in inhibiting plant fungal pathogenic bacteria and application of 4-hydroxycinnamyl aldehyde in preventing and treating plant fungal diseases, and further discloses a product for inhibiting the plant fungal pathogenic bacteria and a product for preventing and treating the plant fungal diseases. Starting from the response of plants to pathogenic bacteria, the metabolite 4-hydroxycinnamyl aldehyde with obvious expression up-regulation in rice plants is detected, the metabolite 4-hydroxycinnamyl aldehyde is also a compound generated by an immune system after the plants cope with external pathogenic bacteria infection, and the research proves that the metabolite 4-hydroxycinnamyl aldehyde has an inhibition effect on various plant pathogenic bacteria, belongs to a broad-spectrum inhibitor, and can be used for preparing a compound for preventing and treating various plant pathogenic bacteria. There is no agent registered with the component in botanical pesticides registered at present, and the invention has important significance for development of environment-friendly novel botanical pesticides or synthesis of lead compounds, and provides technical support for large-scale production and large-area application of the botanical pesticides.

Description

Technical Field

[0001] The invention relates to the technical field of plant protection, and in particular to application of 4-hydroxycinnamaldehyde in preventing and controlling plant fungal diseases. Background Art

[0002] Rice is one of the most important food crops in the world. Effective disease prevention and control is the key to ensuring high and stable rice yields. ) is a soil-borne fungal disease that mainly occurs in the late tillering stage to the panicle differentiation stage of rice. It not only harms the rice leaf sheaths, but also the leaves and rice panicles, seriously affecting the yield and quality of rice. Rhizoctonia solani is a deutero-fungi in the kingdom of fungi that can cause a variety of plant diseases, such as rice damping-off, rapeseed damping-off, sesame damping-off, vegetable damping-off, etc. The pathogen can overwinter in the soil in the form of hyphae in diseased remains or in the form of sclerotia, and infect rice when the temperature rises the following year. Rice fields that have experienced sheath blight often suffer from the disease again every year. In recent years, with the widespread promotion of short-stem and multi-tiller varieties, the adoption of lush cultivation methods, and the continuous increase in the application of nitrogen fertilizers, the occurrence of rice sheath blight has shown an upward trend. It can reduce rice production by 10%-30%, and in severe cases can reduce production by more than 50%. It has now developed into one of the most widely distributed and harmful diseases in my country. Since the disease mainly harms rice leaf sheaths, leaves and rice ears, destroys conductive tissues, and in severe cases, the leaves die, resulting in the inability of rice to head normally or even the death of the entire plant, and is closely related to the field environment, it is difficult to effectively prevent and control in production practice. Therefore, actively carrying out research on prevention and control measures for rice sheath blight is of great significance to the development of my country's rice industry and the quality and safety of agricultural products.

[0003] Common rice diseases include rice blast and false smut. Rice false smut is caused by Ustilaginoideavirens (Cooke) Tak., while rice blast is caused by Magnaporthe grisea (Cooke) Sacc. Magnaporthe grisea can cause rice blast, wheat blast and many other plant diseases.

[0004] The research and development of botanical fungicides, from the perspective of compound structure, there are four main categories of antibacterial active ingredients in plants: terpenoids and their derivatives; nitrogen- and sulfur-containing compounds such as alkaloids, amides and proteins; fatty compounds, mainly long-chain carbon alkanes and fatty acids; aromatic compounds, including phenols, flavonoids and stilbenes, among which essential oils (compounds of esters, aldehydes, ketones, terpenes, etc.) are the most common antibacterial active ingredients in higher plants. At present, there are two main aspects of the development and application of botanical fungicides at home and abroad: one is the direct use of antibacterial plants, that is, directly processing natural products with antibacterial activity (usually crude extracts of active ingredients in the active parts of antibacterial plants) into appropriate dosage forms according to the standards of pesticides to control diseases. The main advantage of this method of use is that it can give play to the synergistic effect of various components in the crude extract, with low investment and short development cycle. Neem is currently recognized internationally as an ideal insecticide and fungicide plant, and is planted on a large scale in many places. Since the first commercial agent Margosan with azadirachtin as the main ingredient was registered in the United States in 1985, many neem preparations have been put into commercial production. These neem preparations are mainly insecticides, and there are also several commercial fungicides, such as the neem preparation TrilogyTriac 90EC, which can be used to prevent and control leaf spot disease, anthracnose, early blight, late blight, leaf spot, downy mildew, powdery mildew, scab, rust, and punch disease of fruit trees and vegetables. Matrine emulsifiable concentrate and matrine aqueous solution developed with Sophora flavescens as raw material can prevent and control a variety of fungal diseases of crops such as grain, fruit trees, and vegetables, such as sheath blight, black spot, ring rot, gray mold, downy mildew, and blight. However, this method of directly using antibacterial plants requires that the active ingredients of antibacterial plants have the advantages of broad spectrum, high efficiency, high content, high stability, low toxicity, ecological safety, and easy extraction. Otherwise, it lacks development and application value. The second is to use the antibacterial active substances in plants as templates to carry out biomimetic synthesis of biologically rational pesticides. my country has used the molecular structure of allicin (trisulfide propene) as a template to derive and synthesize the analogue ethoxyethyl allicin (ethyl thioethanesulfonate), and successfully developed the fungicide 402, which is highly efficient and broad-spectrum, and can widely inhibit a variety of pathogenic bacteria in crops such as grains and oils, cotton, vegetables, fruit trees, flowers, and medicinal materials; Meng Zhaoli and others isolated antibacterial active substances from ginkgo and carried out biomimetic synthesis to develop agricultural fungicides "Green Emperor" and "Yintai"; Japan isolated a fungicide compound containing a malonic acid fork structure from rice plants resistant to rice blast, and used it as a lead compound to develop the fungicide rice blast, which is mainly used to prevent and control rice blast and has certain activity against leafhoppers.

[0005] 4-Hydroxycinnamaldehyde (P-Coumaraldehyde) is a plant-derived compound, and there is no report on its application as a pesticide. Summary of the invention

[0006] Based on a large number of experiments, the present invention discovered a plant-derived compound, 4-hydroxycinnamaldehyde, from rice, and experimentally confirmed the antibacterial activity of the compound against three common pathogens of rice diseases, and experimentally verified its disease prevention effect on rice detached leaves and living plants infected by sheath blight. Based on this, the present invention provides the following technical solutions:

[0007] The first aspect of the present invention provides the use of 4-hydroxycinnamaldehyde in inhibiting plant fungal pathogens, wherein the fungal pathogens include Rhizoctonia solani, Ustilaginoidea virens, and Magnaporthe grisea.

[0008] In the above-mentioned technical scheme for the application of 4-hydroxycinnamaldehyde in inhibiting plant fungal pathogens, the application concentration of 4-hydroxycinnamaldehyde to plant fungal pathogens is 0.3-200 mg / L;

[0009] Preferably, the concentration of 4-hydroxycinnamaldehyde applied to Rhizoctonia solani is 70-200 mg / L, 70-150 mg / L, 70-100 mg / L, or 80-90 mg / L;

[0010] Preferably, the concentration of 4-hydroxycinnamaldehyde applied to Pyricularia oryzae is 8-100 mg / L, 10-80 mg / L, 10-50 mg / L, 10-30 mg / L, or 13-20 mg / L;

[0011] Preferably, the application concentration of 4-hydroxycinnamaldehyde to chlorosclerotium oryzae is 0.3-10 mg / L, 0.3-5 mg / L, 0.4-3 mg / L, or 0.5-2 mg / L.

[0012] The second aspect of the present invention provides a product for inhibiting plant fungal pathogens, wherein the active ingredient comprises 4-hydroxycinnamaldehyde, and the fungal pathogens include Rhizoctonia solani, Ustilaginoidea virens, and Magnaporthe grisea.

[0013] Preferably, the above-mentioned product for inhibiting plant fungal pathogens also includes a solvent for 4-hydroxycinnamaldehyde, the concentration of 4-hydroxycinnamaldehyde in the product is 0.3 to 200 mg / L, and the solvent for 4-hydroxycinnamaldehyde is selected from chloroform, dimethyl sulfoxide or ethanol; preferably, the product also contains an auxiliary agent, and the auxiliary agent includes Tween-80.

[0014] The third aspect of the present invention provides the use of 4-hydroxycinnamaldehyde in preventing and controlling plant fungal diseases, wherein the plant fungal diseases are diseases caused by fungal pathogens, and the fungal pathogens include Rhizoctonia solani, Ustilaginoidea virens, and Magnaporthe grisea.

[0015] In the above-mentioned technical solution for applying 4-hydroxycinnamaldehyde in preventing and controlling plant fungal diseases, the plant fungal diseases are rice sheath blight, rice blast or rice false smut.

[0016] In the above-mentioned technical scheme for applying 4-hydroxycinnamaldehyde in preventing and controlling plant fungal diseases, the application concentration of 4-hydroxycinnamaldehyde is 0.5-1000 mg / L, preferably 50-1000 mg / L or 50-500 mg / L or 50-200 mg / L or 50-150 mg / L or 80-120 mg / L.

[0017] The fourth aspect of the present invention provides a product for preventing and controlling plant fungal diseases, wherein the active ingredient comprises 4-hydroxycinnamaldehyde, wherein the plant fungal diseases are diseases caused by fungal pathogens, and the fungal pathogens include Rhizoctonia solani, Ustilaginoidea virens, and Magnaporthe grisea.

[0018] Preferably, the above-mentioned product for preventing and controlling plant fungal diseases also includes a solvent for 4-hydroxycinnamaldehyde, wherein the concentration of 4-hydroxycinnamaldehyde is 0.5 to 1000 mg / L, and the solvent for 4-hydroxycinnamaldehyde is selected from chloroform, dimethyl sulfoxide, and ethanol; preferably, the product also contains an auxiliary agent, and the auxiliary agent includes Tween-80.

[0019] Preferably, in the above-mentioned product for preventing and controlling plant fungal diseases, the concentration of 4-hydroxycinnamaldehyde is 50-1000 mg / L or 50-500 mg / L or 50-200 mg / L or 50-150 mg / L or 80-120 mg / L.

[0020] The beneficial effect of the present invention is that, starting from the response of the plant to the pathogen, 4-hydroxycinnamaldehyde, a metabolite with significantly upregulated expression in the rice plant, is detected. The compound is also a compound produced by the immune system of the plant in response to the infection of external pathogens. The research of the present invention confirms that the compound has an inhibitory effect on a variety of plant pathogens and is a broad-spectrum inhibitor. No agent registered with this ingredient is found in the currently registered botanical pesticides. The present invention is of great significance for the development of new environmentally friendly botanical pesticides or the synthesis of lead compounds, and provides technical support for the large-scale production and large-scale application of botanical pesticides. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the disease phenotype of rice resistant and susceptible varieties after inoculation with sheath blight.

[0022] Figure 2 is a Venn diagram comparing the differences in the metabolome between inoculated and uninoculated resistant and susceptible varieties.

[0023] Figure 3 This is a graph showing the inhibitory effect of 4-hydroxycinnamaldehyde on the pathogens of rice sheath blight, rice blast and rice false smut.

[0024] Figure 4 This is a graph showing the results of the preventive and control effect of 4-hydroxycinnamaldehyde on rice sheath blight on detached leaves. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with implementation examples, but the present invention is not limited thereby.

[0026] The experimental methods in the following examples are all conventional methods unless otherwise specified; the biological and chemical reagents used in each example are all conventional reagents in the field, laboratory pure grade, and can be obtained commercially unless otherwise specified.

[0027] Example 1. Discovery of plant-derived compound 4-hydroxycinnamaldehyde (P-Coumaraldehyde) in rice sheath blight-resistant strains 1. Experimental materials and methods

[0028] 1.1 Cultivation and inoculation of sheath blight pathogen

[0029] Source of the pathogenic fungus Rhizoctonia solani of rice sheath blight: Rice sheath blight diseased plants were collected from rice planting fields in Tianjin. The pathogen strain isolated from rice sheath blight diseased plants was identified as Rhizoctonia solani through morphology and molecular biology and is now preserved in the Grain and Economic Disease Research Laboratory, Institute of Plant Protection, Tianjin Academy of Agricultural Sciences.

[0030] Inoculation of rice with sheath blight: Use the toothpick inoculation method to inoculate the sheath blight strain onto potato sucrose culture medium, place sterilized toothpicks around it, and culture at 25℃ for 3 days. When the mycelium covers the toothpicks, set them aside for use. During the tillering stage of rice, gently break open the leaf sheaths, insert the toothpicks with sheath blight into the leaf sheaths, restore the leaf sheaths to their original state, and minimize damage to the leaf sheaths.

[0031] 1.2 Survey methods and resistance evaluation criteria for rice varieties infected with sheath blight

[0032] The extended length of the lesions of the inoculated rice plants and the height of the rice plants were measured at the heading stage, and the ratio was calculated according to the following formula: ratio = lesion length / plant height. The resistance of rice varieties Jingang 30 and Shanyou 63 to sheath blight was graded according to the resistance index (see Table 1 for the grading standard).

[0033] Table 1

[0034]

[0035] 1.3 Planting and sampling of experimental materials

[0036] The rice varieties tested were Zhengdao 22 and Xinzhi 1, provided by Henan Seed Station. After inoculation with sheath blight at the tillering stage, the outermost leaves of rice were selected at 0h, 24h, 48h, and 72h after inoculation. Each sample was taken three times, wrapped in tin foil and quickly frozen in liquid nitrogen. The samples were freeze-dried and stored at -80℃ for subsequent metabolite detection.

[0037] 1.4 Metabolome analysis

[0038] Each freeze-dried sample was added with an extraction solvent containing methanol / water (4:1, v:v) and an internal standard (l-2-chlorophenylalanine) of 0.02 mg / mL to obtain leaf metabolites. The samples were ground in a frozen tissue grinder at -10°C and 50 Hz for 6 min, and then sonicated at -20°C for 30 min. They were then centrifuged at 14,000 rpm for 15 min at 4°C. The collected supernatant was used for ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS / MS) analysis.

[0039] Thermo UHPLC system, equipped with ACQUITY UPLC HSS T3 column (100 mm × 2.1 mm id, 1.8 μm; Waters, Milford, USA), used mobile phases A (95% water / 5% acetonitrile + 0.1% formic acid) and B (47.5% acetonitrile / 47.5% isopropanol / 5% water + 0.1% formic acid) to separate metabolites. The mobile phases were 0.1% formic acid in water: acetonitrile (95:5, v / v) (solvent A) and 0.1% formic acid in acetonitrile: isopropanol: water (47.5:47.5, v / v) (solvent B). The injection volume was 5 μL and the flow rate was maintained at 0.3 mL / min. The column temperature was kept constant at 40 °C, and all samples were kept at 4 °C throughout the analysis. Mass spectrometric data were collected on a Thermo UHPLC-Q Exactive HF-X mass spectrometer with ESI source in positive or negative ion mode. The capillary voltage and spray shield were set to 3500 V, the sheath gas low rate and nebulizer gas low rate were set to 50 arb and 13 arb, respectively, and the capillary temperature was 325 ° C. The spectrum was between m / 270 and 1050, and the collision energy was set to 20-40-60 V in MS / MS mode.

[0040] 1.5 Metabolome differential analysis

[0041] All data in this experiment are expressed as the mean ± SE of three biological replicates. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Duncan's multiple range test with a significance level of 5%. The data were preprocessed using Progenesis QI 2.3 (Nonlinear Dynamics, Waters, USA) software. Based on accurate mass, MS / MS fragment spectra and isotope ratio differences, these metabolites were identified by mass spectrometry using reliable biochemical databases such as the Human Metabolome Database (HMDB) (https: / / www.hmdb.ca / ), the Metlin database (https: / / metlin.scripps.edu / ) and the KEGG Compound database (https: / / www.kegg.jp / kegg / compound / ). Multivariate statistical analysis was performed using the R package ropls (Version 1.6.2, https: / / bioconductor.org / packages / release / bioc / html / ropls.html) on the Majorbio cloud platform (https: / / cloud.majorbio.com) (Renet al., 2022). Orthogonal partial least squares discriminant analysis (OPLS-DA) was used to distinguish metabolites between different groups. In the OPLS-DA model, the variable importance in projection (VIP) was determined. The P value was calculated using the one-way paired Student's t test. Differentially expressed metabolites (DAMs) were detected with VIP value > 1 and P value < 0.05 as the criteria.

[0042] 2 Test results

[0043] In this study, two rice varieties with consistent field phenotypes of resistance to sheath blight for three consecutive years were selected. One variety (Zhengdao 22) showed moderate resistance, and the other variety (Xinzhi 1) showed high susceptibility (the disease phenotype after inoculation with sheath blight was as follows: Figure 1 The two rice varieties with obvious differences in resistance to sheath blight were inoculated with sheath blight pathogens. Samples were taken 48 hours after inoculation for non-targeted metabolomics testing, and the uninoculated samples were tested as controls at the same time. Figure 2) compared the metabolome differences of the disease-resistant variety Zhengdao 22 after inoculation (R405_WK1_vs_R405_WK2) and the disease-susceptible variety Xinzhi 1 after inoculation (R391_WK1_vs_R391_WK2). Metabolome analysis found 80 differentially expressed metabolites in the disease-resistant variety Zhengdao 22 and 107 differentially expressed metabolites in the disease-susceptible variety Xinzhi 1. Among them, 4-hydroxycinnamaldehyde (P-Coumaraldehyde) is the only metabolite that is highly expressed in both resistant and susceptible varieties. Analysis shows that this metabolite may be an important metabolite related to disease prevention produced by rice plants in response to pathogen invasion, and it is produced by rice itself.

[0044] Example 2: Inhibitory effect of 4-hydroxycinnamaldehyde (P-Coumaraldehyde) on rice sheath blight, rice blast and rice false smut pathogens.

[0045] 1 Experimental Materials and Methods

[0046] 1.1 Main reagents: 95% pure 4-hydroxycinnamaldehyde (CAS No.: 2538-87-6) powder, purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0047] 1.2 Culture of bacteria and preparation of bacterial cake

[0048] The rice sheath blight pathogen (Rhizoctonia solani), rice blast pathogen (Magnaporthe grisea), and rice false smut pathogen (Ustilaginoidea virens) used in the experiment were isolated, identified, and preserved by the Grain Disease Research Laboratory, Institute of Plant Protection, Tianjin Academy of Agricultural Sciences.

[0049] A clean culture dish with a flat bottom and a diameter of 9 cm was selected, dried and sterilized, and PDA culture medium was poured into it under aseptic operation conditions to make a flat plate. After condensation, the test bacteria were inoculated and cultured in a constant temperature incubator at 25°C. When the mycelium evenly covered the culture dish, the culture medium with bacteria was cut off at the edge of the colony with a puncher with a diameter of 0.5 cm, which was the bacterial cake.

[0050] 1.3 Preparation of virus-infected culture medium

[0051] The preparation of the poisonous culture medium is carried out under aseptic conditions. 0.2g of 4-hydroxycinnamaldehyde is dissolved in 1mL of chloroform and then diluted with sterile water to different concentrations. A certain amount of the calculated agent (according to the range of agent concentration when the antibacterial rate obtained in the preliminary test is 10%-80%) is added to a PDA culture medium at about 40°C (different experimental groups with 4-hydroxycinnamaldehyde concentrations of 100mg / L, 10mg / L, 1mg / L and 0.1mg / L in the culture medium are set), and after being fully shaken and evenly mixed, the mixture is poured into a sterilized culture dish with a diameter of 9cm, and each concentration is repeated 3 to 4 times, and a plate containing sterile water is set as a blank control.

[0052] 1.4 Determination of the toxicity of 4-hydroxycinnamaldehyde to pathogenic bacteria

[0053] The growth rate method was used. The above-mentioned bacterial cakes were transferred to the poisoned culture medium of different concentrations with an inoculation needle, with one cake per dish, facing down, and placed in a constant temperature incubator at 25°C. The colony diameter of sheath blight was investigated after 48 hours of cultivation, and the colony diameter of rice blast and false smut was investigated after 5 days of cultivation.

[0054] 1.5 Calculation of toxicity equation

[0055] The linear regression calculation was performed by computer, with the logarithm of the concentration of the agent as X and the logarithm of the inhibition rate as Y. The toxicity equations of 4-hydroxycinnamaldehyde against Rhizoctonia solani, Rice blast and U. oryzae were obtained, and the effective concentration EC when the inhibition rate was 50% was calculated. 50 The toxicity of the drugs was compared.

[0056] 2 Test results

[0057] 4-Hydroxycinnamaldehyde has different inhibitory effects on three pathogens (see Figure 3 and Table 2), the strongest inhibitory effect on rice smut pathogen, EC 50 The value is 0.5702mg / L; the inhibitory effect on rice blast fungus is second, EC 50 The value is 12.9906mg / L; the inhibitory effect on sheath blight is the weakest, EC 50 The value was 85.2409 mg / L. It can be seen that the differential metabolite 4-hydroxycinnamaldehyde produced by resistant and susceptible rice varieties after inoculation with sheath blight has the effect of inhibiting the growth of rice sheath blight, rice blast and rice false smut pathogens, indicating that rice resistant varieties can resist the infection of pathogens through their own metabolites under the stress of pathogens.

[0058] Table 2. Toxicity of 4-hydroxycinnamaldehyde to three rice pathogens

[0059]

[0060] Example 3: Effect of 4-hydroxycinnamaldehyde (P-Coumaraldehyde) on the prevention and control of rice sheath blight (detached leaves)

[0061] 1 Experimental Materials and Methods

[0062] 1.1 The rice variety is Mongolian rice. During the tillering stage of rice, take the latest leaves grown from the plant, the width of the leaves is 4-5mm, and cut into leaf segments of 5-6cm in length in the middle of the leaves for later use.

[0063] 1.2 Cultivation of rice sheath blight pathogen and preparation of bacterial cake

[0064] Select a clean culture dish with a flat bottom and a diameter of 9 cm, dry and sterilize it, pour in PDA culture medium under aseptic operation conditions, make a flat plate, inoculate the test bacteria after condensation, and culture it in a constant temperature incubator at 25℃. When the hyphae evenly cover the culture dish, use a 0.5cm diameter puncher to cut off the bacterial culture medium at the edge of the colony, which is the bacterial cake.

[0065] 1.34-Hydroxycinnamaldehyde treatment of leaves:

[0066] 4-Hydroxycinnamaldehyde powder with a purity of 95% was dissolved in chloroform and prepared into five concentrations of 1000 mg / L, 100 mg / L, 10 mg / L, 1 mg / L, and 0 mg / L (ck), and then 1% (v / v) of surfactant Tween-80 was added to disperse the 4-hydroxycinnamaldehyde evenly. After mixing, it was sprayed on the surface of the leaf segment. Each leaf segment was sprayed with 1 ml of the agent. Four rice leaf segments of the same treatment were placed on a toothpick covered with double-layer filter paper and absorbed with water (10 ml). Each treatment was repeated four times. The prepared sheath blight cake was inoculated in the middle of two of the leaf segments. The leaf segment that was not inoculated with bacteria was used as a control. The culture dish cover was covered, and the entire plate was placed in a 25°C incubator. The extension length of the lesions was investigated at 72 hours, and the control effect was calculated.

[0067] 2 Test results

[0068] The test results are shown in Table 3 and Figure 4 When the concentration of 4-hydroxycinnamaldehyde is 1000 mg / L, the prevention effect on sheath blight is 86.5%. When the concentration of the agent is 100 mg / L, the prevention effect on sheath blight is 81.1%. These two concentrations show good prevention effects. When the concentration of the agent is 1 mg / L~10 mg / L, the prevention effect drops rapidly to 16.2%~35.1%. It can be seen that 4-hydroxycinnamaldehyde has a good effect on preventing and controlling the occurrence of sheath blight, and it can reach more than 80% at 100 mg / L.

[0069] Table 3. The protective effect of 4-hydroxycinnamaldehyde on sheath blight (detached leaves)

[0070]

[0071] Example 4: Effect of 4-hydroxycinnamaldehyde (P-Coumaraldehyde) on rice sheath blight control (rice plants)

[0072] 1 Experimental Materials and Methods

[0073] 1.1 The rice variety is lement. The sterilized rice seeds are sown in plastic pots (11 cm high, 12.5 cm in diameter) filled with a special rice seedling medium, 25 seeds are sown in each pot, and the plants are ready for use after they grow to tillering.

[0074] 1.2 Cultivation and inoculation of rice sheath blight pathogen

[0075] The rice sheath blight pathogen strain was inoculated onto potato sucrose culture medium, sterilized toothpicks were placed around it, and cultured at 25°C for 3 days. When the mycelium covered the toothpicks, they were set aside for use. During the tillering stage of rice, the leaf sheaths were gently opened and the toothpicks with sheath blight pathogen were inserted into the leaf sheaths to restore the leaf sheaths to their original state and minimize damage to the leaf sheaths.

[0076] 1.3 Hydroxycinnamaldehyde treatment of rice plants

[0077] 95% pure 4-hydroxycinnamaldehyde powder was dissolved in chloroform to prepare a 100 mg / L solution, and then 1% (v / v) of surfactant Tween-80 was added. After mixing, the mixture was evenly sprayed on the surface of rice plants. 20 mL of the solution was sprayed on each pot. Clean water was used as a control. Each treatment was repeated 4 times. After 60 minutes, when the solution was fully absorbed, the prepared toothpick with sheath blight bacteria was gently placed into the outermost leaf sheath of the plant for inoculation. The plant was placed in a 28°C incubator. The extension length of the lesions was investigated after 10 days, and the prevention effect was calculated.

[0078] 2 Experimental results

[0079] The protective effect of 4-hydroxycinnamaldehyde (P-Coumaraldehyde) on rice sheath blight is shown in Table 4. It can be seen that when the compound is sprayed at a concentration of 100 mg / L, the protective effect on rice sheath blight is 69.9%, and the plants are darker green than the control.

[0080] Table 4. Effect of 4-hydroxycinnamaldehyde on the control of rice sheath blight

[0081]

Claims

The application of 1.4-hydroxycinnamaldehyde in inhibiting plant fungal pathogens is characterized by: The fungal pathogens include Rhizoctonia solani, Ustilaginoidea virens, and Magnaporthe grisea.

2. The use according to claim 1, characterized in that: The application concentration of 4-hydroxycinnamaldehyde to plant fungal pathogens is 0.3-200 mg / L; Preferably, the concentration of 4-hydroxycinnamaldehyde applied to Rhizoctonia solani is 70-200 mg / L, 70-150 mg / L, 70-100 mg / L, or 80-90 mg / L; Preferably, the concentration of 4-hydroxycinnamaldehyde applied to Pyricularia oryzae is 8-100 mg / L, 10-80 mg / L, 10-50 mg / L, 10-30 mg / L, or 13-20 mg / L; Preferably, the application concentration of 4-hydroxycinnamaldehyde to chlorosclerotium oryzae is 0.3-10 mg / L, 0.3-5 mg / L, 0.4-3 mg / L, or 0.5-2 mg / L.

3. A product for inhibiting plant fungal pathogens, characterized in that: The active ingredient contains 4-hydroxycinnamaldehyde, and the fungal pathogens include Rhizoctonia solani, Ustilaginoideavirens, and Magnaporthe grisea.

4. The product according to claim 3, characterized in that: The product also includes a solvent for 4-hydroxycinnamaldehyde, the concentration of 4-hydroxycinnamaldehyde in the product is 0.3-200 mg / L, and the solvent for 4-hydroxycinnamaldehyde is selected from chloroform, dimethyl sulfoxide or ethanol; preferably, the product also contains an auxiliary agent, and the auxiliary agent includes Tween-80. The application of 5.4-hydroxycinnamaldehyde in preventing and controlling plant fungal diseases is characterized by: The plant fungal diseases are diseases caused by fungal pathogens, and the fungal pathogens include Rhizoctonia solani, Ustilaginoidea virens, and Magnaporthe grisea.

6. The use according to claim 5, characterized in that: The plant fungal disease is rice sheath blight, rice blast or rice false smut.

7. The use according to claim 5, characterized in that: The application concentration of 4-hydroxycinnamaldehyde is 0.5-1000 mg / L, preferably 50-1000 mg / L or 50-500 mg / L or 50-200 mg / L or 50-150 mg / L or 80-120 mg / L.

8. A product for preventing and controlling plant fungal diseases, characterized in that: The active ingredient contains 4-hydroxycinnamaldehyde. The plant fungal disease is a disease caused by fungal pathogens, and the fungal pathogens include Rhizoctonia solani, Ustilaginoidea virens, and Magnaporthe grisea.

9. The product according to claim 8, characterized in that: The invention also comprises a solvent for 4-hydroxycinnamaldehyde, wherein the concentration of 4-hydroxycinnamaldehyde is 0.5-1000 mg / L, and the solvent for 4-hydroxycinnamaldehyde is selected from chloroform, dimethyl sulfoxide and ethanol; preferably, the product also comprises an auxiliary agent, and the auxiliary agent comprises Tween-80.

10. The product according to claim 9, characterized in that: The concentration of 4-hydroxycinnamaldehyde is 50-1000 mg / L or 50-500 mg / L or 50-200 mg / L or 50-150 mg / L or 80-120 mg / L.

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