Nanometer preparation for efficiently preventing and controlling rice blast as well as preparation method and application of nanometer preparation

Abstract

The invention discloses a nano preparation for efficiently preventing and controlling rice blast as well as a preparation method and application thereof, and belongs to the technical field of rice blast prevention and control. The nano-selenium preparation comprises chitosan, nano-selenium, gamma-irradiated nano-montmorillonite and a 1% (v / v) acetic acid solution, the concentration of the chitosan is 0.01%. 2% (m / v), the concentration of the nano-selenium is 0.01%. 1% (m / v), and the concentration of the nano-montmorillonite subjected to gamma irradiation is 0.1%. 1% (m / v). The method has the beneficial effects that after the chitosan and the nano-selenium material are sprayed to the rice leaves, a protective film is formed on the surfaces of the rice leaves, and after gamma-irradiated montmorillonite is added, the uniformity and durability of the protective film can be improved, the acting effect of the nano-selenium protective film is improved, rain wash is effectively resisted, infection of pyricularia oryzae is efficiently blocked, and the yield of the rice leaves is increased. The spore germination process of the pyricularia oryzae is inhibited, the rice blast can be effectively prevented, and the food safety is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rice blast prevention and control, and particularly relates to a nano preparation for preventing and controlling rice blast, and a preparation method and application thereof. BACKGROUND

[0002] Rice is one of the most important food crops in the world, and more than half of the world's population relies on rice as their main food. Rice fungal disease is a disease that restricts the safe production of rice, which can cause a decrease in rice yield and an increase in planting costs. In particular, rice blast caused by Magnaporthe oryzae is one of the world's most serious diseases that affect rice, and poses a great threat to global food production, causing losses that can feed more than 60 million people. Due to the rapid variation of the pathogen and the resistance of the pathogen to chemical control, the current traditional crop cultivation methods or chemical control methods cannot effectively inhibit the occurrence and spread of Magnaporthe oryzae.

[0003] Magnaporthe oryzae follows a strict semi-vital nutritional life history. When the conidia of Magnaporthe oryzae contact the host surface through external force, it recognizes the hydrophobic interface of the plant surface, differentiates to form a polar growing germ tube, and differentiates to form a special infection structure, an appressorium, at the end of the germ tube. After the appressorium forms, it penetrates the host epidermis to infect the host cells and enters the vital nutritional infection stage. After penetrating the host epidermis, the peg differentiates to form a long primary infection hypha that enters the host. The primary infection hypha expands in the late stage and differentiates to produce new infection hyphae when it invades adjacent cells and enters adjacent host cells through intercellular filaments. In the late stage of the infection stage, the pathogen expands and kills plant cells, promoting plant cell death. The occurrence of rice blast seriously threatens global food security and sustainable agricultural development. It is of great significance to develop targeted agents and provide efficient and low-toxicity control strategies.

[0004] Chinese patent application document with publication number CN108770850A discloses a composition for inhibiting rice blast and application thereof. The composition includes jasmonic acid and salicylic acid, and the molar ratio of the jasmonic acid and the salicylic acid is 0.5:1-1.5:1. The combination of jasmonic acid and salicylic acid can effectively target fungi in different nutritional stages of Magnaporthe oryzae and form a comprehensive control. The patent also provides the application of the above composition in preventing and controlling rice blast. Experimental verification shows that the incidence rate of rice blast treated by the above composition can be reduced from 60% to 20% after 120 hours of infection with Magnaporthe oryzae. However, the patent is only directed to plant diseases caused by semi-vital parasitic fungi, and has certain limitations, and therefore needs to be further researched and improved. SUMMARY

[0005] The technical problem solved by the present application is how to solve the poor inhibition effect of rice blast in the prior art, and to provide a nano selenium preparation for preventing and controlling rice blast and a preparation method thereof.

[0006] The present application solves the above technical problems by the following technical means: One of the technical solutions of the present application is a nano selenium preparation for preventing and controlling rice blast, which comprises chitosan, nano selenium, gamma-irradiated nano montmorillonite and 1-3% (v / v) acetic acid solution; based on the volume of the 1-3% (v / v) acetic acid solution, the concentration of chitosan is 0.1‰-2% (m / v), the concentration of nano selenium is 0.01-0.1% (m / v), and the concentration of gamma-irradiated nano montmorillonite is 1‰-1% (m / v).

[0007] Preferably, the preparation method of the nano selenium comprises the following steps: (1) Culturing spore bacillus (CCTCC NO: M 20221472) rich in nano selenium, adding sodium selenite in the fermentation broth so that the concentration of sodium selenite in the fermentation broth is 5 mM, and culturing for 144-168 hours to obtain a nano selenium-containing fermentation broth, wherein the effective viable bacterial count is 1.6×10 10 -2.0×10 10 cfu / mL; (2) Ultrasonically treating the fermentation broth obtained in step (1) at a power of 100-300 W for 30-60 minutes, centrifuging at 8000 rpm for 10-20 minutes, and removing the supernatant to obtain nano selenium.

[0008] Preferably, the particle size of the nano selenium is 30-60 nm.

[0009] Preferably, the gamma-irradiated nano montmorillonite is obtained by irradiating montmorillonite with a high-energy electron beam accelerator at a dose of 10-400 kGy for 1-24 hours.

[0010] Preferably, the concentration of chitosan is 0.5-1.5% (m / v), the concentration of nano selenium is 0.05-0.08% (m / v), and the concentration of gamma-irradiated nano montmorillonite is 8‰-0.5% (m / v).

[0011] The second technical solution of the present application is a preparation method of the above-mentioned nano selenium preparation for preventing and controlling rice blast, which comprises the following steps: First, prepare an acetic acid solution with a concentration of 1-3% (v / v); According to the above proportions, sequentially add chitosan, nano selenium and gamma-irradiated nano montmorillonite, and mix uniformly to obtain the nano selenium preparation.

[0012] Preferably, the preparation method comprises the following steps: First, configure an acetic acid solution with a concentration of 1-3% (v / v); Add chitosan, mix at 60-80℃ for 2-4h to obtain a uniform chitosan solution; Add nano-selenium, mix at a speed of 500-1000 rpm for 30-60 min to obtain a uniform nano-selenium chitosan solution; Add gamma-irradiated nano-montmorillonite, and oscillate and mix at a speed of 400-6000 rpm for 2-6h to obtain a final concentration of 0.1‰-2% (m / v) of chitosan, a final concentration of 0.01-0.1% (m / v) of nano-selenium, and a final concentration of 1‰-1% (m / v) of gamma-irradiated nano-montmorillonite.

[0013] Preferably, the pH value of the chitosan solution is adjusted to 4.0-6.0 to ensure its stability.

[0014] The third technical scheme of the present application provides the use of the above nano-selenium preparation in the prevention and control of rice blast.

[0015] The fourth technical scheme of the present application provides a method for preventing and controlling rice blast, which comprises the following steps: spraying the above nano-selenium preparation on the leaves of rice at the breaking stage and / or the full-bloom stage of rice.

[0016] Preferably, the spraying amount is 25-35 L / acre, and more preferably 30 L / acre.

[0017] The present application has the following advantages: 1. The present application uses chitosan combined with nano-selenium, which forms a protective film on the surface of rice leaves after spraying. The addition of gamma-irradiated montmorillonite improves the uniformity and durability of the protective film, enhances the effect of the nano-selenium protective film, effectively resists rainwater erosion, efficiently blocks the invasion of Pyricularia oryzae, and inhibits the spore germination process of Pyricularia oryzae, thereby effectively preventing rice blast and ensuring food security.

[0018] 2. When the percentage of each raw material is lower than the above range, there is no significant prevention and control effect. When the percentage of each raw material exceeds the above range, the prevention and control effect does not increase, but the prevention and control cost increases, and the use of too high a concentration will cause the leaves to turn yellow and affect the normal growth of rice.

[0019] 3. The quality of montmorillonite does not change significantly after gamma irradiation, but the microstructure of montmorillonite changes after gamma irradiation, enhancing the bactericidal effect of montmorillonite. Nano-selenium and gamma-irradiated montmorillonite have a synergistic effect, which can reduce the combined invasion of rice blast on the leaves. Chitosan enhances the adhesion effect, prolongs the action time of the nano-selenium protective film, and enhances the prevention and control effect of rice blast.

[0020] 4. Compared with the prior art, the present invention has a stronger effect in controlling rice blast disease. After spraying, it can reduce the incidence of rice blast disease by more than 90%, and is more environmentally friendly. Attached Figure Description

[0021] Figure 1 This describes the inhibition of *Pyrrosia lingua* plate by the nano-selenium formulation in Example 1 of this invention; Figure 2 The diagram shows the inhibition of the nano-selenium preparation in the incubator in Example 1 of the present invention, where A is a comparison diagram of rice growth and B is a comparison diagram of inhibition. Figure 3 The images show the field control effect of the nano-selenium formulation in Example 2 of this invention, where A is a comparison of rice growth and B is a comparison of inhibition. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical terms used below have the same meaning as understood by those skilled in the art.

[0023] Unless otherwise specified, the test materials and reagents used in the following examples are commercially available or prepared by known methods.

[0024] Unless otherwise specified, all techniques or conditions described in the embodiments can be performed in accordance with the techniques or conditions described in the literature in this field or in the product manual. Unless otherwise specified, the quantitative experiments in the following embodiments are all repeated three times or more, and the results are averaged.

[0025] Example 1: A nano-selenium formulation for controlling rice blast disease comprises chitosan, nano-selenium, γ-irradiated nano-montmorillonite, and a 2% (v / v) acetic acid solution. Based on the volume of the 2% (v / v) acetic acid solution, the concentration of chitosan is 0.5% (m / v), the concentration of nano-selenium is 0.05% (m / v), and the concentration of γ-irradiated nano-montmorillonite is 8‰ (m / v).

[0026] The preparation method of the above-mentioned nano-selenium formulation for controlling rice blast disease specifically includes the following steps: (1) Montmorillonite was irradiated with a high-energy electron beam accelerator with a dose of 40 kGy for 18 hours to obtain γ-irradiated montmorillonite. (2) Preparation of nano selenium: cultivate the bacillus (CCTCC NO: M 20221472) enriched with nano selenium, add sodium selenite in the fermentation broth so that the concentration of sodium selenite in the fermentation broth is 5 mM, cultivate for 150 hours, and obtain the fermentation broth, wherein the effective viable bacterial count is 1.8 x 10 10 cfu / mL; The obtained fermentation broth is subjected to ultrasonic treatment with a power of 250 w for 45 minutes, centrifuged at 8000 rpm for 15 minutes, and the supernatant is removed to obtain nano selenium (particle size 30-60 nm); (3) Prepare an acetic acid solution with a concentration of 2% (v / v), add chitosan, and mix uniformly at 70°C for 3 hours to obtain a uniform chitosan solution; (4) Add nano selenium to the chitosan solution and mix uniformly at a speed of 600 rpm for 40 min to obtain a uniform nano selenium chitosan solution.

[0027] (5) Add the nano montmorillonite subjected to γ irradiation to the nano selenium chitosan solution, and oscillate and mix at a speed of 800 rpm for 3 h to obtain a nano selenium preparation for preventing and controlling rice blast.

[0028] The prepared nano selenium preparation is used for plate inhibition of rice Magnaporthe oryzae as shown in Figure 1 .

[0029] The prepared nano selenium preparation of the present example is applied to prevent and control rice blast of potted rice: Potted rice (Nanjing 46) treatment: (1) Spray the water-cultured rice leaves with fine mist once, and the amount is determined by the fact that the sprayed parts are all wet; (2) Culture a large number of Magnaporthe oryzae spores in a laboratory incubator, and dilute them to 1000 U / mL of Magnaporthe oryzae spore suspension for field spore inoculation; (3) Spray the treated rice with Magnaporthe oryzae spores; (4) Statistically analyze the incidence of potted rice 7-15 days after treatment (fifty leaves are counted for each treatment, and the disease index DI is obtained).

[0030] The present example can reduce the incidence of rice blast by more than 61% (as shown in Figure 2 ), effectively reducing the harm of rice blast to rice yield and quality.

[0031] Example 2: The prepared nano selenium preparation of Example 1 is applied to prevent and control rice blast in the field: Field rice (Nanjing 46) treatment at the breaking stage and the heading stage: (1) On the broken period of rice field, the rice leaves are uniformly sprayed with fine mist once, with a dosage of 30 L per mu, and the second uniform spraying is carried out at the rice earing stage; (2) A large number of rice blast spores are cultured in a laboratory incubator, and diluted into a 1000 U / mL rice blast spore suspension for field spore inoculation; (3) The sprayed rice is sprayed with rice blast spores, and the spraying amount is the same as that of Example 1; (4) The incidence of the field rice 20-45 days after the treatment is counted, and the counting method is the same as that of Example 1.

[0032] It is found that the rice blast incidence rate is reduced by more than 88% (as shown in Figure 3 ), and the harm of rice blast to rice yield and quality is effectively reduced.

[0033] Example 3 A nano-selenium preparation for preventing and controlling rice blast, which is composed of chitosan, nano-selenium, gamma-irradiated nano-montmorillonite and 1% (v / v) acetic acid solution; taking the volume of 1% (v / v) acetic acid solution as a reference, the concentration of chitosan is 2% (m / v), the concentration of nano-selenium is 0.1% (m / v), and the concentration of gamma-irradiated nano-montmorillonite is 1% (m / v).

[0034] The preparation method of the above-mentioned nano-selenium preparation for preventing and controlling rice blast, specifically includes the following steps: (1) The montmorillonite is irradiated with a high-energy electron beam accelerator with a dose of 10 kGy for 24 hours to obtain gamma-irradiated montmorillonite; (2) Preparation of nano-selenium: cultivate the nano-selenium-enriched Bacillus (CCTCC NO: M 20221472), add sodium selenite to the fermentation broth so that the concentration of sodium selenite in the fermentation broth is 5 mM, and cultivate for 144 hours to obtain the fermentation broth, wherein the effective viable bacterial count is 1.6 x 10 10 cfu / mL; The obtained fermentation broth is subjected to ultrasonic treatment with a power of 100 w for 60 minutes, centrifuged at 8000 rpm for 10 minutes, and the supernatant is removed to obtain nano-selenium (particle size 30-60 nm); (3) Prepare a 1% (v / v) acetic acid solution, add chitosan, and mix uniformly at 60°C for 4 hours to obtain a uniform chitosan solution; (4) Add nano-selenium to the chitosan solution and mix uniformly at a speed of 1000 rpm for 30 min to obtain a uniform nano-selenium chitosan solution.

[0035] (5) adding the gamma-irradiated nanometer montmorillonite into the nanometer selenium chitosan solution, and oscillating and mixing at a rotation speed of 400 rpm for 6 hours to obtain the nanometer selenium preparation for preventing and controlling rice blast.

[0036] Example 4: The nanometer selenium preparation for preventing and controlling rice blast is composed of chitosan, nanometer selenium, gamma-irradiated nanometer montmorillonite and 3% (v / v) acetic acid solution; taking the volume of the 3% (v / v) acetic acid solution as a reference, the concentration of the chitosan is 0.1‰ (m / v), the concentration of the nanometer selenium is 0.01% (m / v), and the concentration of the gamma-irradiated nanometer montmorillonite is 1‰ (m / v).

[0037] The preparation method of the nanometer selenium preparation for preventing and controlling rice blast comprises the following steps: (1) irradiating the montmorillonite with a high-energy electron beam accelerator at a dose of 10 kGy for 24 hours to obtain gamma-irradiated montmorillonite; (2) preparing nanometer selenium: culturing the nanometer selenium-enriched Bacillus (CCTCC NO: M 20221472), adding sodium selenite into the fermentation broth so that the concentration of the sodium selenite in the fermentation broth is 5 mM, and culturing for 168 hours to obtain the fermentation broth, wherein the effective viable bacterial count is 2.0×10 10 cfu / mL; carrying out ultrasonic treatment on the obtained fermentation broth at a power of 300 w for 30 minutes, centrifuging at 8000 rpm for 20 minutes, removing the supernatant, and obtaining nanometer selenium (particle size: 30-60 nm); (3) preparing a 3% (v / v) acetic acid solution, adding chitosan, and uniformly mixing at 80°C for 2 hours to obtain a uniform chitosan solution; (4) adding nanometer selenium into the chitosan solution, and uniformly mixing at a rotation speed of 500 rpm for 60 min to obtain a uniform nanometer selenium chitosan solution.

[0038] (5) adding the gamma-irradiated nanometer montmorillonite into the nanometer selenium chitosan solution, and oscillating and mixing at a rotation speed of 6000 rpm for 2 hours to obtain the nanometer selenium preparation for preventing and controlling rice blast.

[0039] The above examples are only used to illustrate the technical solutions of the present application, but not limit the same; although the present application has been described in detail with reference to the foregoing examples, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A nano-selenium preparation for preventing and controlling rice blast, characterized in that, The chitosan, nano-selenium, nano-montmorillonite irradiated by gamma rays and 1-3% (v / v) acetic acid solution; the concentration of the chitosan is 0.1‰-2% (m / v) based on the volume of the 1-3% (v / v) acetic acid solution, the concentration of the nano-selenium is 0.01-0.1% (m / v), and the concentration of the nano-montmorillonite irradiated by gamma rays is 1‰-1% (m / v).

2. The nano-selenium preparation according to claim 1, characterized in that, The preparation method of the nano-selenium comprises the following steps: (1) Culturing the nano-selenium-enriched Bacillus (CCTCC NO: M 20221472) in the fermentation broth, adding sodium selenite to the fermentation broth so that the concentration of sodium selenite in the fermentation broth is 5 mM, culturing for 144-168 hours, and obtaining a nano-selenium-containing fermentation broth, wherein the effective viable cell count is 1.6×10 10 -2.0×10 10 cfu / mL; (2) The fermentation bacterial liquid obtained in step (1) is subjected to ultrasonic treatment with a power of 100-300 w for 30-60 min, and centrifuged at 8000 rpm for 10-20 min, and the supernatant is removed to obtain the nano-selenium.

3. The nano-selenium preparation according to claim 1, characterized in that, The nano-montmorillonite irradiated by gamma rays is obtained by irradiating the montmorillonite with a high-energy electron beam accelerator with a dose of 10-400 kGy for 1-24 h.

4. The nano-selenium preparation according to claim 1, characterized in that, The concentration of the chitosan is 0.5-1.5% (m / v), the concentration of the nano-selenium is 0.05-0.08% (m / v), and the concentration of the nano-montmorillonite irradiated by gamma rays is 8‰-0.5% (m / v).

5. A method of preparing the nano-selenium preparation according to any one of claims 1 to 4, characterized in that, The preparation method comprises the following steps: First, an acetic acid solution with a concentration of 1-3% (v / v) is prepared; The chitosan, nano-selenium and nano-montmorillonite irradiated by gamma rays are added in proportion and mixed uniformly to obtain the nano-selenium preparation.

6. The production method according to claim 5, wherein The preparation method comprises the following steps: First, an acetic acid solution with a concentration of 1-3% (v / v) is prepared; The chitosan is added and mixed uniformly at 60-80 ℃ for 2-4 h to obtain a uniform chitosan solution; The nano-selenium is added and mixed uniformly at a rotation speed of 500-1000 rpm for 30-60 min to obtain a uniform nano-selenium chitosan solution; The nano-montmorillonite irradiated by gamma rays is added and mixed by oscillation at a rotation speed of 400-6000 rpm for 2-6 h, so that the final concentration of the chitosan is 0.1‰-2% (m / v), the final concentration of the nano-selenium is 0.01-0.1% (m / v), and the final concentration of the nano-montmorillonite irradiated by gamma rays is 1‰-1% (m / v).

7. The production method according to claim 6, wherein The pH value of the chitosan solution is adjusted to 4.0-6.

0.

8. The nano-selenium preparation of any one of claims 1-4 or prepared by the preparation method of any one of claims 5-7 is applied to the prevention and control of rice blast.

9. A method for preventing and controlling rice blast in rice, characterized by, The preparation method comprises the following steps: The nano-selenium preparation of any one of claims 1-4 is sprayed on the leaves of rice at the breaking stage and / or the earing stage of rice.

10. The method for controlling rice blast of rice according to claim 9, wherein, The spraying amount is 25-35 L / acre.

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