CN110742076B

CN110742076B - Application of liquiritin in preventing and treating crop oomycetes and fungal diseases

Info

Publication number: CN110742076B
Application number: CN201911018787.3A
Authority: CN
Inventors: 刘裴清; 陈庆河; 李本金; 翁启勇; 王荣波
Original assignee: Institute of Plant Protection of FAAS
Current assignee: Institute of Plant Protection of FAAS
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2021-05-14
Anticipated expiration: 2039-10-24
Also published as: CN110742076A

Abstract

The invention discloses an application of liquiritin in preventing and treating oomycetes and fungal diseases, which is a plant bactericide prepared by using liquiritin as an active ingredient and adding auxiliary materials acceptable in agriculture and pharmacy, or directly using liquiritin to prevent and treat oomycetes and fungal diseases of crops. The liquiritin used in the invention is natural in source, has no toxic or side effect, is safe to people and livestock, can be used as a low-toxicity and effective antibacterial component, is not easy to cause pathogenic microorganisms to generate drug resistance, can be used for preventing and treating crop diseases such as tomato gray mold, cauliflower sclerotinia, pepper phytophthora blight, phytophthora blight and the like caused by phytophthora capsici, cryptophyte phytophthora crypthecae and the like, and has great potential.

Description

Application of liquiritin in preventing and treating crop oomycetes and fungal diseases

Technical Field

The invention relates to application of liquiritin in preventing and treating crop oomycetes and fungal diseases.

Background

Plant diseases caused by plant pathogenic oomycetes cause great harm to the production of crops and forest trees in China, and the annual average economic loss is as high as hundreds of billions of yuan. At present, the main means for fungus and oomycete diseases in agricultural production is to use a large amount of chemical pesticides. However, since the action site of the chemical pesticide is single, the resistance is more and more obvious and shows a more and more serious trend along with the increase of the use times and the prolonging of the service life. Therefore, the search for safe alternative medicaments of high-efficiency broad-spectrum chemical bactericides is urgent, and natural products such as active ingredients of traditional Chinese medicines show great application potential in the aspect of disease control.

Radix Glycyrrhizae (Glycyrrhiza uralensis: (C)Glycyrrhizae Radix et Rhizoma) Widely distributed in northeast, Anhui, Yunnan, Xinjiang, inner Mongolia and other places of China. The composition is rich and complex, and mainly contains compounds such as flavonoid, triterpenes, coumarin and the like. The research on the pharmacological action of liquorice mainly focuses on compounds such as glycyrrhizin, total flavonoids, glycyrrhetinic acid, glycyrrhizin, polysaccharides and the like.Isoliquiritigenin, liquiritigenin, isoliquiritin and liquiritin are flavonoid components in liquorice, wherein isoliquiritin and liquiritin are flavonoid compounds. Since the 60's of the 20 th century, the pharmacological actions of licoflavone have received much attention. Many researches show that certain flavonoids compounds in liquorice not only have an inhibiting effect on various pathogens, but also can reduce the toxicity of antibacterial drugs in other chemical drugs, and are natural antibacterial drugs with great potential. The result of researches on the bacteriostatic effect of flavonoid quercetin on staphylococcus aureus and escherichia coli by Hongxiangwei and the like shows that the quercetin can achieve the bacteriostatic purpose by destroying cell wall structures and the like to cause the loss or decline of normal physiological functions of bacteria. A large number of documents show that the flavonoids have obvious inhibition effects on different bacteria and have no obvious inhibition effect on filamentous fungi, and the action research of licoflavone-liquiritin on the prevention and control of crop fungi such as botrytis cinerea, sclerotinia sclerotiorum, phytophthora capsici and phytophthora crypthecoralis and oomycete diseases is not seen at home and abroad at present.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a new application of liquiritin.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention claims and protects the application of liquiritin in preventing and treating crop oomycetes and fungal diseases, or the application of a plant bactericide prepared from liquiritin in preventing and treating crop oomycetes and fungal diseases.

The concentration of liquiritin in the plant bactericide is 200-1600 mug/mL, and the plant bactericide also contains auxiliary materials acceptable in the agricultural pharmacy.

It can be used for preventing and treating phytophthora capsici (a)Phytophthora capsici) Phytophthora crypthecogenica (A), (B), (CPhytophthora cryptogea) Botrytis cinerea (A. cinerea)Botrytis cinerea Pers.) And Sclerotinia sclerotiorum (A), (B), (C), (Sclerotinia sclerotiorum) And the like, and particularly comprises crop epidemic diseases and fungal diseases such as tomato gray mold, cauliflower sclerotinia rot, pepper epidemic disease, phytophthora blight of grass and the like.

The disease control is mainly carried out by prevention, the principle of medicine application is adopted in advance, and preventive medicine application and early medicine application are carried out when diseases occur under the conditions of high temperature and high humidity. The method comprises mixing liquiritin or plant bactericide prepared from liquiritin with 0.02% (V/V) Tween 20 to obtain medicinal liquid, and spraying onto leaf surface to prevent dripping; the liquid medicine was diluted 10-fold (0.1 g/mL) with water at the time of actual spraying.

The invention has the following remarkable advantages:

the liquiritin is natural, has no toxic or side effect, is an effective bacteriostatic component with low toxicity, is not easy to cause pathogenic microorganisms to generate drug resistance, can be used for preventing and treating crop diseases such as tomato gray mold, cauliflower sclerotinia rot, pepper phytophthora blight, phytophthora blight and the like and fungal diseases, and has great potential.

Drawings

FIG. 1 shows the effect of different concentrations of glycyrrhizin on the growth of hyphae of phytophthora capsici and other plant pathogens, wherein A is 200, 400, 800, 1200, 1600 mug/mL (from left to right) on the growth of the hyphae of phytophthora capsici, and B is the statistical analysis of the growth of different concentrations of glycyrrhizin on the hyphae of phytophthora cryptophyrae, phytophthora capsici, botrytis cinerea and sclerotinia sclerotiorumP< 0.05，**P<0.01。

FIG. 2 shows the effect of glycyrrhizin treatment on the hyphal morphology of Phytophthora crypthecodinii (Pm), Phytophthora capsici (Pc), Botrytis cinerea (Bc) and Sclerotinia sclerotiorum (Ss) (200 ×), wherein the left panel is a control group and the right panel is a treatment group.

FIG. 3 shows the effect of glycyrrhizin treatment on pathogenic spore production, wherein the left panel is the control group and the right panel is the treatment group.

FIG. 4 is a graph showing the effect of liquiritin treatment on Sclerotinia sclerotiorum sporulation, wherein A is a control group to which liquiritin was not added and B is a treatment group to which liquiritin was added.

FIG. 5 shows the variation of the conductivity of different mycelia after liquiritin treatment.

FIG. 6 shows SY TOX staining test (200X) of different hyphae after liquiritin treatment.

FIG. 7 shows the disease resistance of the capsicum (A), pea (B) and tomato (C) after the liquiritin treatment.

FIG. 8 is liquiritin treatmentFluorescent quantitative amplification peak diagram of phytophthora capsici pathogenic gene and expression condition diagram of encoding CRN and 76RT genesP<0.05，**P<0.01。

Detailed Description

In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.

Example 1: on a clean bench, firstly, respectively inoculating the separated Botrytis cinerea (Bc), Sclerotinia sclerotiorum (Ss), Phytophthora capsici (Pc) and Phytophthora cryptica (Pm) to a PDA culture medium, after dark culture at 25 ℃ for 5d, respectively cutting hypha blocks of 0.5 multiplied by 0.5cm at the edges of bacterial colonies by using an operation blade, additionally placing the hypha blocks in new PDA culture dishes (the content of liquiritin is 0, 200, 400, 800, 1200 and 1600 mug/mL) containing liquiritin with series concentrations, and dark culture at 25 ℃ for 5 d. The results show that: the liquiritin has strong bacteriostatic activity on plant pathogenic bacteria, can obviously inhibit the growth of pathogenic bacteria, and has the action effect influenced by the concentration of the liquiritin, wherein the inhibition effect is stronger when the concentration of the liquiritin is higher (see figure 1).

Example 2: on a clean bench, firstly, respectively inoculating separated Botrytis cinerea (Bc), Sclerotinia sclerotiorum (Ss), Phytophthora capsici (Pc) and Phytophthora cryptica (Pm) to a PDA culture medium, after 5 days of dark culture at 25 ℃, cutting a 0.5 multiplied by 0.5cm hypha block at the edge of a colony by using an operation blade, additionally placing the hypha block in a new PDA culture dish containing 1200 mu g/mL of liquiritin, and carrying out dark culture at 25 ℃ for 5 days so as not to add liquiritin control. Microscopic observation shows that: compared with the blank group, the liquiritin has obvious inhibition effect on the hypha growth and the spore capsule formation of botrytis cinerea, sclerotinia sclerotiorum, phytophthora capsici and phytophthora cryptogeotrichum; after the hyphae are treated by liquiritin, the hyphae are deformed, branches are obviously increased, the spacing is shortened, the terminal hyphae tend to become larger and thicker (see figure 2), and the spore (or sclerotium) producing capability is obviously weakened (see figure 3).

Example 3: on a clean bench, firstly, respectively inoculating separated Botrytis cinerea (Bc), Sclerotinia sclerotiorum (Ss), Phytophthora capsici (Pc) and Phytophthora cryptica (Pm) to a PDA culture medium, after 5 days of dark culture at 25 ℃, cutting a 0.5 multiplied by 0.5cm hypha block at the edge of a colony by using an operation blade, additionally placing the hypha block in a new PDA culture dish containing 1200 mu g/mL of liquiritin, and carrying out dark culture at 25 ℃ for 5 days so as not to add liquiritin control. Cell membrane permeability results indicate that: after the liquiritin treatment, the conductivity of the phytophthora capsici is obviously reduced, and the conductivity of other phytophthora capsici is obviously increased (see figure 5); SY TOX staining test shows that the integrity of the cell membranes of Botrytis cinerea, Sclerotinia sclerotiorum and Phytophthora cryptica is damaged (see FIG. 6).

Example 4: selecting pepper and pea leaves with the same leaf age and size, cutting off the pepper and pea leaves together with leaf stalks for standby, and preparing fresh tomatoes. Then, liquiritin is prepared into liquid medicine (containing 0.02% (V/V) Tween 20) with the concentration of 800 mug/mL, and the liquid medicine is sprayed on pepper leaves, pea leaves and tomato fruits. The spraying liquid medicine and the distilled water are 1 mL/leaf by taking the distilled water as a blank control. After spraying for 24 h, punching the bacterial cakes at the edges 1/3 of the bacterial colonies of phytophthora capsici, botrytis cinerea and sclerotinia sclerotiorum cultured for 3 d by using a puncher with the diameter of 5 mm, inoculating 1 bacterial cake to each leaf or fruit, and repeating the treatment for 5 times. Culturing at room temperature in dark for 3 days, and observing the disease condition of leaves and tomatoes. The results show that: the scabs formed by phytophthora capsici, botrytis cinerea and sclerotinia on the liquiritin agent treated leaves were all significantly smaller than the control leaves (see fig. 7); the fluorescence quantitative analysis of the glycyrrhetinic acid glycoside treated phytophthora capsici finds that: the expression level of the genes encoding the virulence related proteins such as CRN and 76RT is significantly reduced, indicating that liquiritin increases host disease resistance by inhibiting the expression of the virulence related genes (see FIG. 8).

The results show that the liquiritin has obvious inhibition effect on the growth and the pathogenicity of botrytis cinerea, sclerotinia sclerotiorum, phytophthora capsici and cryptophyta cryptogeon, which shows that the liquiritin has great potential as a plant bactericide and can promote the prevention and the treatment of other crop diseases.

Claims

1. The application of the liquiritin in preventing and treating the crop oomycetes and fungal diseases is characterized by being used for preventing and treating the crop oomycetes and fungal diseases caused by phytophthora capsici, cryptophyma cryptophyta, botrytis cinerea and sclerotinia sclerotiorum.

2. The application of the plant bactericide prepared by utilizing the liquiritin in preventing and treating crop oomycetes and fungal diseases is characterized by being used for preventing and treating crop oomycetes and fungal diseases caused by phytophthora capsici, cryptophyma cryptophyrantha, botrytis cinerea and sclerotinia sclerotiorum.

3. The use of the plant bactericide prepared from glycyrrhizin for controlling crop oomycetes and fungal diseases according to claim 2, wherein the concentration of glycyrrhizin in the plant bactericide is 200-1600 μ g/mL.

4. The use of the plant bactericide prepared from liquiritin for controlling oomycetes and fungal diseases of crops as claimed in claim 2, wherein the plant bactericide further comprises an agriculturally and pharmaceutically acceptable auxiliary material.