Application of butterfly in preventing and treating soybean downy mildew

Abstract

The application discloses application of butterfly mycosin in prevention and treatment of soybean phytophthora, and belongs to the technical field of agricultural disease prevention and biological pesticide. The application researches and finds that the living body inhibition index of the butterfly mycosin on the soybean phytophthora is better than that of the existing chitin synthase inhibitor nikkomycin Z, the relative biomass of the soybean phytophthora is reduced by more than 90% under the condition of 100 muM concentration, and the application has the effect of preventing and treating the soybean root rot. The application range of the butterfly mycosin is expanded from the medical field to the agricultural fungicide field, and the application of the butterfly mycosin in prevention and treatment of the oomycetes diseases caused by the soybean phytophthora is realized.

Description

Technical Field

[0001] This invention belongs to the field of agricultural disease control and biological pesticide technology, specifically involving the application of the natural compound doxycycline in the control of soybean Phytophthora. Background Technology

[0002] Soybean root rot, caused by Phytophthora sojae, is one of the most common sources of disease in soybean production.

[0003] In the creation of new green pesticides, chitin synthase is considered an ideal molecular target with great potential and high safety because it is widely found in pathogens (such as fungi, oomycetes and pests) and not found in plants and mammals.

[0004] For a long time, the development of pesticides targeting chitin synthases has been slow due to the lack of accurate three-dimensional structural information. Recent cutting-edge research, focusing on the chitin synthase (PsChs1) of *Phytophthora indicum*, has successfully resolved its three-dimensional structure at the atomic level under different catalytic states and elucidated the binding mechanism between existing active small molecules (such as nikolinazole Z and NikZ) and this enzyme. This breakthrough provides a crucial structural foundation for the precise development of green pesticides targeting PsChs1.

[0005] However, clarifying the binding mechanism has not completely overcome the existing efficacy bottlenecks. Existing chitin synthase inhibitors, such as nicotinic acid Z, have failed to show effective inhibitory activity against specific pathogens such as Phytophthora soybeanis in practical applications because they are difficult to bind effectively to the active site of chitin synthase.

[0006] Currently, there is still a significant research gap in highly active, naturally derived inhibitors targeting PsChs1, which limits the development of related targeted bactericides. Summary of the Invention

[0007] In view of the deficiencies in the prior art, this invention proposes the application of doxycycline in the prevention and control of soybean Phytophthora.

[0008] This invention provides the application of the compound doxycycline in the control of Phytophthora sojae.

[0009] Butylcholine, CAS number 93908-02-2, chemical formula C 27 H 21 Cl2N3O7, The structural formula is: .

[0010] This invention provides the application of the compound hytophthoramycin in the preparation of an agricultural fungicide for the prevention and control of plant diseases caused by Phytophthora sojae.

[0011] In some embodiments, the plant disease caused by Phytophthora soybeanis is soybean root rot.

[0012] This invention provides the application of the compound doxycycline in the preparation of a chitin synthase PsChs1 inhibitor.

[0013] The present invention provides a method for preventing soybean root rot caused by Phytophthora indica, comprising applying an effective dose of the compound bufos or an agricultural fungicide composition containing the compound bufos to plants susceptible to Phytophthora indica, plant seeds or soil in which the plants grow.

[0014] In some embodiments, the application method includes foliar spraying, soil irrigation, or seed treatment; wherein the seed treatment includes soaking, mixing, or coating seeds.

[0015] In some embodiments, the effective concentration of the compound lecithin during application is 10 mg / L to 100 mg / L.

[0016] In some embodiments, the application period includes before soybean sowing, during sowing, or during the seedling stage.

[0017] In some embodiments, the seed treatment is typically carried out before or during sowing, and the foliar spraying or soil irrigation is carried out during the soybean sowing period, emergence period, or seedling growth period.

[0018] In summary, compared with the prior art, the present invention achieves the following technical effects: (1) This invention expands the application scope of butterflymycin from the pharmaceutical field to the field of agricultural fungicides through research, realizing its application in the prevention and control of oomycete diseases caused by soybean phytophthora.

[0019] (2) Provides a naturally sourced inhibitor that targets chitin synthase (PsChs1), which complements the variety of naturally sourced inhibitors for this target.

[0020] (3) The present invention found that the in vivo inhibition index of Phytophthora soybeanis by doxycycline is better than that of the existing chitin synthase inhibitor nicotinic acid Z; at a concentration of 100 μM, it reduces the relative biomass of Phytophthora soybeanis by more than 90%, and has the effect of preventing and controlling soybean root rot. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a photograph of the compound phagocytoma (product number R913148) on living soybean tissue infected with Phytophthora indicum.

[0023] Figure 2 The effect of the compound doxycycline (product number R913148) on soybean lesions infected by Phytophthora in soybean tissue is shown in Figure A. Figure B shows the statistical graph of the width of soybean lesions in each treatment group and the statistical graph of the relative biomass of Phytophthora in each treatment group. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] Rebeccamycin is a tryptophan dimer isolated from Streptomyces and belongs to the topoisomerase I inhibitor class, exhibiting significant in vitro antitumor activity. Its structural analog, 9-methoxyrebeccamycin, produced by the bacterium *Pseudomonas anthelmintica*, displays similar pharmacological properties and is considered an important candidate molecule for the development of novel antitumor drugs. Professor Zhang Guisheng's team at Henan Normal University obtained an invention patent for the synthesis of rebeccamycin analogs in 2012 (application publication number CN102898489 A), and has advanced its antitumor activity research through structural optimization.

[0026] However, to date, no literature has reported the inhibitory effect of doxycycline and its structural analogs on Phytophthora sojae. This invention breaks with the existing understanding that this compound is limited to the pharmaceutical field, and through screening studies, it has been discovered for the first time that doxycycline and its structural analogs can effectively control Phytophthora sojae. Research shows that doxycycline, as a highly active, naturally derived inhibitor targeting PsChs1, provides a novel framework for the development of new green agricultural fungicides.

[0027] The doxycycline used in the examples was purchased from McLean, catalog number R913148.

[0028] The present invention will be further described below with reference to the embodiments.

[0029] Example 1: Preparation of test compound and control group (1) Test compound: Butterflymycin (R913148), with concentration gradients of 20 μM, 50 μM and 100 μM.

[0030] (2) Negative controls: blank group (CK), 1% DMSO treatment group.

[0031] (3) Positive / reference control: 20 μM Nikomycin Z (NikZ), 20 μM Metalaxyl.

[0032] Example 2: Determination of the inhibitory activity of dactylymycin against in vivo infection by Phytophthora soybeanis Healthy and plump soybean seeds were soaked for 4 hours in the prepared solutions of the tested compounds listed above. The treated seeds were then placed on sterile foam, and sprouts emerged after 3 days. These seeds were inoculated with *Phytophthora sojae* and cultured for another 3 days. Once obvious disease was observed, the width of lesions and relative biomass were measured in each group to evaluate the actual control efficacy of each compound against *Phytophthora sojae*. Results are shown below. Figure 1 and Figure 2 .

[0033] The results showed that the doxycycline treatment group inhibited lesion spread in a concentration-dependent manner within the range of 20 μM to 100 μM. In the 100 μM treatment group, the lesion width was less than 5 mm, and the relative biomass of *Phytophthora sojae* was reduced by more than 90%. At the same concentration of 20 μM, the lesion width and biomass in the doxycycline treatment group were significantly lower than those in the negative control group (P ≤ 0.01); and its inhibitory effect was significantly better than that of the known chitin synthase inhibitor nicotinic acid Z (P ≤ 0.05).

[0034] The doxycycline of this invention can efficiently target the chitin synthase (PsChs1) of Phytophthora soybeanis. Compared with the control agent nicotinic acid Z in the prior art, the doxycycline proposed in this invention can efficiently bind to the active site of PsChs1, showing excellent inhibitory activity against Phytophthora soybeanis. Its control efficacy against soybean root rot is significantly better than that of nicotinic acid Z, and it has extremely high development potential and application value.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Application of the compound doxycycline in the control of Phytophthora sojae.

2. Application of the compound Phytophthoramycin in the preparation of agricultural fungicides for the prevention and control of plant diseases caused by Phytophthora sojae.

3. The application according to claim 2, characterized in that, The plant disease caused by Phytophthora indicum is soybean root rot.

4. Application of the compound davidimycin in the preparation of chitin synthase PsChs1 inhibitor.

5. A method for preventing and controlling soybean root rot caused by Phytophthora indicum, characterized in that, This includes applying an effective dose of the compound bufos or an agricultural fungicide composition containing the compound bufos to plants susceptible to soybean Phytophthora infestation, plant seeds, or the soil in which the plants grow.

6. The method according to claim 5, characterized in that, The application methods include foliar spraying, soil irrigation, or seed treatment; wherein the seed treatment methods include soaking, mixing, or coating seeds.

7. The method according to claim 5, characterized in that, When applied, the effective concentration of the compound davidimycin is 10 mg / L to 100 mg / L.

8. The method according to claim 5, characterized in that, The application period includes before soybean sowing, during sowing, or during the seedling stage.

9. The method according to claim 6, characterized in that, The seed treatment is carried out before or during sowing, and the foliar spraying or soil irrigation is carried out during the soybean sowing period, emergence period, or seedling growth period.

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