Inducer for inducing cucumber to resist corynespora leaf spot disease, induction method and application

Abstract

The invention relates to the technical field of phytopathology and agricultural biology, and particularly provides an inducer for inducing cucumber to resist corynespora leaf spot, an induction method and application. The inducer comprises caffeic acid, and the optimal application scheme is that the concentration of caffeic acid is 100 mu mol / L, the spraying interval is 3 days, and the caffeic acid is sprayed for three times in total. The inducer and the induction method provided by the invention are used for inducing cucumber to resist the corynespora leaf spot disease, have the characteristics of environmental protection and high efficiency, are beneficial to reducing the use of chemical pesticides, and ensure the safety, yield and quality of cucumber production.

Description

Technical Field

[0001] The invention relates to the fields of plant pathology and agricultural biotechnology, and in particular provides an inducer, an induction method and an application for inducing cucumber resistance to corynespora leaf spot disease. Background Art

[0002] Cucumber is an annual vine or climbing herb of the Cucurbitaceae family. It is widely planted around the world for its unique taste and rich nutritional value and is deeply loved by consumers. Cucumber has slender stems, palm-shaped leaves with serrated edges and a surface covered with fine hairs. Its fruit is long or cylindrical, green or yellow-green when immature, and some varieties may turn yellow after maturity, with a smooth surface or nodules. Cucumber likes warmth, water, fertilizer, and light, and has certain requirements for soil conditions. Before planting, you need to choose fertile, loose, well-drained sandy loam or sandy loam, and deep plowing and sufficient base fertilizer should be applied. The sowing time is mostly selected in spring or autumn, depending on local climatic conditions and variety characteristics. Before sowing, the seeds need to be soaked and germinated to improve the germination rate and uniformity. During the growth period of cucumbers, timely watering, fertilization, soil cultivation, and plant adjustment management measures are required to promote plant growth and fruit development.

[0003] Cucumber Corynespora leaf spot, also known as target spot and brown spot, is a disease caused by Corynespora polytomata, which mainly harms cucumber leaves. In severe cases, it can spread to petioles, stems, vines and fruits, especially in high temperature and high humidity environments. At present, the prevention and control of this disease mostly relies on chemical pesticides, but long-term use can easily lead to drug resistance in pathogens and pose a potential threat to the environment and food safety. Therefore, it is particularly important to find environmentally friendly and efficient disease prevention and control methods.

[0004] Caffeic acid is a phenolic compound widely found in plants. It is the main precursor of lignin synthesis in plants and the main intermediate of the phenylalanine pathway for the synthesis of phenylalanine or L-tyrosine. It has significant antioxidant and antibacterial effects. The synthesis pathway of caffeic acid: First, phenylalanine is converted into cinnamate by the catalysis of phenylalanine ammonia-lyase (PAL); then, cinnamate 4-hydroxylase (C4H) further hydrolyzes it into p-coumaric acid; finally, p-coumaric acid is converted into caffeic acid by hydroxylation. Caffeic acid and its derivatives are related to the tolerance of plants to biotic and abiotic stresses, including pathogen attack, low and high temperature stress, ultraviolet light, drought, heavy metal stress and salinity stress. Studies have found that plants usually have a higher accumulation of caffeic acid in the body when facing abiotic stress, and these caffeic acids help plants resist adverse stress. In cucumber, caffeic acid can induce plants to develop resistance to low temperature, but its application in cucumber resistance to Coryneformis leaf spot has not been reported. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an inducer, an induction method and an application for inducing cucumber resistance to Corynespora leaf spot disease.

[0006] The present invention is achieved by providing an inducer for inducing cucumber resistance to coryneformis leaf spot disease, wherein the inducer comprises caffeic acid.

[0007] Preferably, the concentration of caffeic acid is 50-200 μmol·L -1 .

[0008] More preferably, the concentration of caffeic acid is 100 μmol·L -1 .

[0009] The present invention provides a method for inducing cucumber resistance to Corynespora leaf spot disease, using the above-mentioned inducer for inducing cucumber resistance to Corynespora leaf spot disease, and the method comprises the following steps:

[0010] Step 1: dissolving caffeic acid powder in water to prepare a caffeic acid solution;

[0011] Step 2: Process cucumber seeds and germinate them;

[0012] Step 3: When the cucumber seedlings grow to the two-leaf and one-heart stage, use caffeic acid solution to spray the entire plant. Repeat the spraying at regular intervals to induce resistance to Corynespora leaf spot disease in the cucumber seedlings.

[0013] Preferably, in step 1, the concentration of caffeic acid in the caffeic acid solution is 50-200 μmol·L -1 .

[0014] Further preferably, in step 1, the concentration of caffeic acid in the caffeic acid solution is 100 μmol·L -1 .

[0015] Further preferably, in step 2, the cucumber seeds are treated by heat shock method, and then placed in an artificial climate box at 18°C / 25°C for 2 days to carry out moisture preservation and germination.

[0016] More preferably, in step 3, the interval between two sprayings is 1-3 days, and the spraying is performed 1-3 times in total.

[0017] More preferably, in step 3, the interval between two sprayings is 3 days, and the spraying is performed 3 times in total.

[0018] The present invention provides an application of the above-mentioned inducer for inducing cucumber resistance to Corynespora leaf spot, which is used for inducing cucumber to produce resistance to Corynespora leaf spot.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] The inducer and induction method provided by the present invention can induce cucumber to resist Corynespora leaf spot disease, which is environmentally friendly and highly efficient, helps to reduce the use of chemical pesticides, and ensures the safety, yield and quality of cucumber production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0022] Figure 1 This is a comparison chart of the inhibitory activity of the control group and different concentrations of caffeic acid on Corynespora multilocus;

[0023] Figure 2 This is the disease phenotype of cucumber Coryspore leaf spot under the control group and the optimal application scheme of caffeic acid. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] The caffeic acid used in the present invention was purchased from McLean, and the cucumber variety tested was Xintai Mici.

[0026] Example 1: Inhibitory activity of different concentrations of caffeic acid against Corynespora polymyxinii.

[0027] Under sterile conditions, caffeic acid was quantitatively added to the pre-melted PDA medium, shaken and poured into the culture dish in equal amounts to make a 50 μmol·L -1 , 100 μmol·L -1 , 150 μmol·L -1 , 200 μmol·L -1 The control group was treated with ddH2O and 35% dicyanoproconazole, a fungicide. The bacterial cake was cut with a sterile punch and inoculated in the center of the plate with the mycelium facing down and incubated at 28°C. Figure 1 As shown, it can be seen that adding 35% dicyanoproconazole to the culture medium can significantly inhibit the growth of Multi-main Corynespora, while the control group and different concentrations of caffeic acid have no inhibitory effect on the growth of Multi-main Corynespora, that is, caffeic acid is not an antibacterial agent or a fungicide.

[0028] Example 2: Caffeic acid induces resistance to cucumber Coryspore leaf spot.

[0029] Step 1: Dissolve an appropriate amount of caffeic acid powder in distilled water to prepare a caffeic acid solution of a certain concentration. Preferably, the concentration of caffeic acid is 0 μmol·L -1 , 50 μmol·L-1 , 100 μmol·L -1 , 150 μmol·L -1 , 200 μmol·L -1 The specific concentration is adjusted according to the experimental results.

[0030] Step 2: Place the heat-shocked cucumber seeds in a culture dish filled with gauze and filter paper to keep them moist and germinate, and place them in an artificial climate box at 18℃ / 25℃ for 2 days.

[0031] Step 3: After the cucumbers germinate, plant them in seedling pots. When they have two leaves and one heart, spray the entire cucumber plant with the prepared caffeic acid solution to fully induce resistance in the cucumbers. The specific number of applications and intervals will be adjusted according to the experimental plan.

[0032] Step 4: 24 hours after the last spraying of caffeic acid solution, inoculate cucumber Coryspore leaf spot pathogen and regularly observe the growth of cucumber plants and the occurrence of leaf diseases. The induction effect of caffeic acid on cucumber resistance to Coryspore leaf spot pathogen was evaluated by comparing the disease index and other indicators of the control group and the treatment group.

[0033] Step 5: Grading standard for cucumber coryneform leaf spot disease: Grade 0, no lesions; Grade 1, lesion area accounts for less than 5% of the total leaf area; Grade 3, lesion area accounts for 6%~25% of the total leaf area; Grade 5, lesion area accounts for 26%~50% of the total leaf area; Grade 7, lesion area accounts for 51%~75% of the total leaf area; Grade 9, lesion area accounts for more than 76% of the total leaf area. Disease index = Σ (number of diseased leaves at each level × relative level value) / (total number of leaves surveyed × highest level representative value) × 100.

[0034] Table 1 shows the effects of different concentrations of caffeic acid on inducing resistance to Corynespora leaf spot in cucumber under the same conditions. Table 2 shows the effects of different spraying times on inducing resistance to Corynespora leaf spot in cucumber under the same conditions. Table 3 shows the effects of different intervals on inducing resistance to Corynespora leaf spot in cucumber under the same conditions. It can be seen that the best application scheme of caffeic acid for inducing resistance to Corynespora leaf spot in cucumber is a concentration of 100 μmol·L -1 , each spraying interval is 3 days, a total of 3 sprayings, through Figure 2 The induction effect of the optimal administration regimen can be demonstrated.

[0035] Table 1

[0036]

[0037] Table 2

[0038]

[0039] Table 3

[0040]

[0041] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. An inducer for inducing cucumber resistance to Corynespora leaf spot, characterized in that: The inducer includes caffeic acid.

2. The inducer for inducing cucumber resistance to Corynespora leaf spot according to claim 1, characterized in that The concentration of caffeic acid is 50-200 μmol·L -1 .

3. The inducer for inducing cucumber resistance to Corynespora leaf spot according to claim 2, characterized in that The concentration of caffeic acid is 100 μmol·L -1 .

4. A method for inducing resistance of cucumber to Corynespora leaf spot, characterized in that: Using the inducer for inducing cucumber resistance to Corynespora leaf spot disease according to claim 1, the method comprises the following steps: Step 1: dissolving caffeic acid powder in water to prepare a caffeic acid solution; Step 2: Process cucumber seeds and germinate them; Step 3: When the cucumber seedlings grow to the two-leaf and one-heart stage, use caffeic acid solution to spray the entire plant. Repeat the spraying at regular intervals to induce resistance to Corynespora leaf spot disease in the cucumber seedlings.

5. The method for inducing resistance of cucumber to Corynespora leaf spot according to claim 4, characterized in that: In step 1, the concentration of caffeic acid in the caffeic acid solution is 50-200 μmol·L -1 .

6. The method for inducing resistance of cucumber to Corynespora leaf spot according to claim 5, characterized in that: In step 1, the concentration of caffeic acid in the caffeic acid solution is 100 μmol·L -1 .

7. The method for inducing resistance of cucumber to Corynespora leaf spot according to claim 4, characterized in that: In the step 2, the cucumber seeds are treated by heat shock method, and then placed in an artificial climate box at 18°C / 25°C for 2 days to moisturize and accelerate germination.

8. The method for inducing resistance of cucumber to Corynespora leaf spot according to claim 4, characterized in that: In step 3, the interval between two sprayings is 1-3 days, and the spraying is performed 1-3 times in total.

9. The method for inducing resistance of cucumber to Corynespora leaf spot according to claim 8, characterized in that: In step 3, the interval between two sprayings is 3 days, and the spraying is performed 3 times in total.

10. Use of the inducer for inducing cucumber resistance to Corynespora leaf spot according to claim 1, characterized in that: Used to induce resistance to Coryneformis leaf spot in cucumber.

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