CN112553085A - Non-toxic rice blast strain for preventing and controlling rice blast and application thereof - Google Patents

Abstract

The invention is applicable to the technical field of microbial engineering, and provides a nontoxic magnaporthe grisea strain for preventing and controlling magnaporthe grisea and application thereof, wherein the magnaporthe grisea is named as magnaporthe grisea M16-1, and the preservation number of the magnaporthe grisea is CCTCC NO: M2020677. In addition, the preparation method of the fermentation liquor of the rice blast fungi comprises the following steps: inoculating the magnaporthe grisea to a PDA culture medium for activation culture, and then inoculating the magnaporthe grisea to a PDB culture medium for fermentation culture to obtain the fermentation liquor. The invention uses the M16-1 strain fermentation liquor to excite the immune reaction of rice plants to pathogenic bacteria, resists the infection of pathogenic bacteria and realizes the biological control of rice blast. The M16-1 strain fermentation liquid can excite broad-spectrum disease resistance of rice, and has no problems of environmental pollution, food pollution, drug resistance of pathogenic bacteria and the like unlike the control of rice blast by using chemical pesticide to kill or inhibit the growth of pathogenic bacteria.

Description

Non-toxic rice blast strain for preventing and controlling rice blast and application thereof

Technical Field

The invention belongs to the technical field of microbial engineering, and particularly relates to a nontoxic rice blast strain for preventing and controlling rice blast and application thereof.

Background

The rice is a main grain crop in the world, more than half of the population in the world takes rice as staple food, and the high and stable yield of the rice is the core of the grain safety in the world. The rice blast caused by the rice blast germs is the most destructive disease in the world rice production, and the annual yield loss of the rice is enough to live 6 million people. The main measures adopted for preventing and controlling the rice blast in the production at present are prevention and control by using disease-resistant varieties and chemical pesticides.

Among them, breeding and utilizing disease-resistant varieties are the most economical and effective strategies for preventing and treating rice blast, but most of the current disease-resistant varieties are vertical resistant varieties based on the theory of 'gene to gene', and the resistance is easily lost due to new toxic strains of the rice blast fungus. In addition, the chemical pesticide has the characteristic of quickly and efficiently preventing and treating the rice blast by inhibiting the growth of pathogenic bacteria, but the long-term use of the chemical pesticide not only brings serious harm to the environment and human health, but also causes the failure of preventing and treating the rice blast because the pathogenic bacteria generate drug resistance to the pesticide.

Disclosure of Invention

The embodiment of the invention aims to provide a nontoxic rice blast strain for preventing and controlling rice blast, and aims to solve the problems in the background technology.

The embodiment of the invention is realized by that a nontoxic rice blast strain for preventing and controlling rice blast, named Magnaporthe oryzae M16-1, is preserved in China Center for Type Culture Collection (CCTCC) 11, 2 and 2020, with the preservation address of Wuhan university at Bayijiashan mountain in Wuchang district, Wuhan city, Hubei China and the preservation number of M2020677.

Another purpose of the embodiment of the invention is to provide an application of the non-toxic Magnaporthe grisea in preventing and controlling Magnaporthe grisea.

Another object of the embodiments of the present invention is to provide a method for preparing a fermentation broth of a non-virulent rice blast strain for controlling rice blast, comprising the steps of:

inoculating the magnaporthe grisea to a PDA culture medium for activation culture, and then inoculating the magnaporthe grisea to a PDB culture medium for fermentation culture to obtain the fermentation liquor.

As a preferable scheme of the embodiment of the invention, the PDA culture medium comprises the following components per liter: 180-220 g of potatoes, 10-15 g of agar powder and 18-22 g of cane sugar.

As another preferable scheme of the embodiment of the invention, each liter of the PDB culture medium comprises the following components: 180-220 g of potatoes and 18-22 g of cane sugar.

As another preferred embodiment of the present invention, OD of the fermentation broth₆₀₀＞1.2。

Another object of the embodiments of the present invention is to provide a fermentation broth of Pyricularia oryzae prepared by the above-mentioned preparation method.

The embodiment of the invention also aims to provide application of the fermentation liquor of the magnaporthe grisea in preventing and controlling rice blast.

As another preferable scheme of the embodiment of the invention, the using method of the rice blast fungus fermentation liquor comprises the following steps:

and spraying the fermentation liquor of the rice blast fungi at the tillering stage and/or the pre-heading stage of the rice.

The embodiment of the invention uses the non-toxic rice blast fungus M16-1 strain fermentation liquor to stimulate the immune response of rice plants to pathogenic bacteria, resists the infection of pathogenic bacteria and realizes the biological control of rice blast. The fermentation liquid of the rice blast fungus M16-1 strain can stimulate broad-spectrum disease resistance of rice, and has no problems of environmental pollution, food pollution, drug resistance of pathogenic bacteria and the like unlike the control of rice blast by using chemical pesticides to kill or inhibit the growth of pathogenic bacteria. In addition, the nontoxic strain has the same living environment as the pathogenic bacteria, and the application effect is stable and is not influenced by the environment. In practical application, the strain fermentation liquor has good effect of inducing broad-spectrum rice blast resistance when being used for rice in various growth periods of laboratories and fields, and is simple to operate, environment-friendly and efficient.

In conclusion, compared with the existing rice blast control technology, the invention has the following advantages:

(1) the invention uses the nontoxic rice blast strain fermentation liquor to excite the immune reaction of rice plants to pathogenic bacteria, thereby resisting the infection of pathogenic bacteria and preventing the occurrence of rice blast, being a broad-spectrum resistance and overcoming the potential risk of causing diseases of rice varieties due to the appearance of new toxic strains.

(2) The avirulent rice blast strain provided by the invention can be used as a pathogenic bacteria signal (relative to a vaccine for preventing certain human diseases which is well known by people) to excite the immune response of rice plants to pathogenic bacteria so as to realize biological control on rice blast, and different from the rice blast control by killing or inhibiting the growth of the pathogenic bacteria by using chemical pesticides, the avirulent rice blast strain can not bring the problems of environmental pollution, food pollution, drug resistance of the pathogenic bacteria and the like. In addition, the nontoxic strain has the same living environment as the pathogenic bacteria, and the application effect is stable and is not influenced by the environment.

Drawings

FIG. 1 is a graph showing the control effect of the fermentation broth of M16-1 strain provided in example 1 on the blast of black millet of the susceptible rice Lijiang Xin Tu. Wherein CK denotes: inoculating pathogenic rice blast A7203-9 or A7203-8 by spraying 72 hours after inoculating sterile water; t means: the M16-1 strain fermentation broth is inoculated with Magnaporthe grisea A7203-9 or A7203-8 after being treated for 72 hours.

FIG. 2 is a graph showing the control effect of the fermentation broth of M16-1 strain provided in example 1 on 4 single-gene rice seedling blight. Wherein CK denotes: inoculating pathogenic rice blast bacteria A7203-8(A) and A7203-9(B) by spraying 72 hours after inoculating with sterile water; t means: the M16-1 strain fermentation broth is inoculated with Magnaporthe grisea A7203-8(A) and A7203-9(B) after being treated for 72 hours.

FIG. 3 is a schematic diagram showing the plot field distribution and plot rice planting pattern of example 7. Wherein, A is a schematic diagram of field distribution in a community, and B is a schematic diagram of a rice planting mode in the community.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

M16-1 strain used in the following examples was named Magnaporthe oryzae M16-1, which was deposited at the China Center for Type Culture Collection (CCTCC) at 11/2/2020, with the preservation address of Wuhan university at the Bayinyao mountain Log in Wuchang district, Wuhan, Hubei, China and the preservation number of M2020677.

Example 1

The embodiment provides M16-1 strain fermentation liquor, and the preparation method comprises the following steps:

s1, mixing 200g of potatoes, 13g of agar powder and 20g of cane sugar which are boiled and filtered by two layers of gauze, and fixing the volume to 1000mL by using purified water to obtain a PDA culture medium for later use; 200g of potato and 20g of cane sugar which are boiled and filtered by two layers of gauze are mixed, and the volume is fixed to 1000mL by using purified water, so that the PDB culture medium is obtained for later use.

S2, inoculating the M16-1 strain stored on the filter paper sheet or the test tube inclined plane to the PDA culture medium for activation culture for 5 days, then picking out outer bacterial colony circle blocks by using an inoculating needle, putting the outer bacterial colony circle blocks into a culture bottle or a culture tank filled with the PDB culture medium for fermentation culture for 5 days, and obtaining M16-1 strain fermentation liquor after the bacterial liquid turns black; wherein the mass of the bacteria is about 16cm during fermentation culture²The temperature is controlled at 28 ℃, the oscillation speed is controlled at 180 rpm/min, and the OD of the fermentation liquor of the M16-1 strain is controlled₆₀₀>1.2。

Example 2

The embodiment provides M16-1 strain fermentation liquor, and the preparation method comprises the following steps:

s1, mixing 180g of potatoes, 10g of agar powder and 18g of cane sugar which are boiled and filtered by two layers of gauze, and fixing the volume to 1000mL by using purified water to obtain a PDA culture medium for later use; mixing 180g of boiled and filtered potatoes and 18g of cane sugar through two layers of gauze, and fixing the volume to 1000mL by using purified water to obtain a PDB culture medium for later use.

S2, inoculating the M16-1 strain stored on the filter paper sheet or the test tube inclined plane to the PDA culture medium for activation culture for 4 days, then picking out outer bacterial colony circle blocks by using an inoculating needle, putting the outer bacterial colony circle blocks into a culture bottle or a culture tank filled with the PDB culture medium for fermentation culture for 4 days, and obtaining M16-1 strain fermentation liquor after the bacterial liquid turns black; wherein the mass of the bacteria is about 16cm during fermentation culture²/L，Controlling the temperature at 28 deg.C, controlling the oscillation speed at 180 rpm/min, and controlling the OD of the fermentation liquid of M16-1 strain₆₀₀>1.2。

Example 3

The embodiment provides M16-1 strain fermentation liquor, and the preparation method comprises the following steps:

s1, mixing 220g of potatoes, 15g of agar powder and 22g of cane sugar which are boiled and filtered by two layers of gauze, and fixing the volume to 1000mL by using purified water to obtain a PDA culture medium for later use; 220g of potatoes which are well boiled and filtered by two layers of gauze and 22g of cane sugar are mixed, and purified water is used for fixing the volume to 1000mL to obtain a PDB culture medium for later use.

S2, inoculating the M16-1 strain stored on the filter paper sheet or the test tube inclined plane to the PDA culture medium for activation culture for 5 days, then picking out outer bacterial colony circle blocks by using an inoculating needle, putting the outer bacterial colony circle blocks into a culture bottle or a culture tank filled with the PDB culture medium for fermentation culture for 6 days, and obtaining M16-1 strain fermentation liquor after the bacterial liquid turns black; wherein the mass of the bacteria is about 16cm during fermentation culture²The temperature is controlled at 28 ℃, the oscillation speed is controlled at 180 rpm/min, and the OD of the fermentation liquor of the M16-1 strain is controlled₆₀₀>1.2。

Example 4

The embodiment provides M16-1 strain fermentation liquor, and the preparation method comprises the following steps:

s1, mixing 190g of potatoes, 12g of agar powder and 19g of cane sugar which are boiled and filtered by two layers of gauze, and fixing the volume to 1000mL by using purified water to obtain a PDA culture medium for later use; 190g of boiled potato and 19g of sucrose which are filtered by two layers of gauze are mixed, and purified water is used for fixing the volume to 1000mL to obtain a PDB culture medium for later use.

S2, inoculating the M16-1 strain stored on the filter paper sheet or the test tube inclined plane to the PDA culture medium for activation culture for 4 days, then picking out outer bacterial colony circle blocks by using an inoculating needle, putting the outer bacterial colony circle blocks into a culture bottle or a culture tank filled with the PDB culture medium for fermentation culture for 5 days, and obtaining M16-1 strain fermentation liquor after the bacterial liquid turns black; wherein the mass of the bacteria is about 16cm during fermentation culture²The temperature is controlled at 28 ℃, and the oscillation speed is controlled at 180 rpM/min, and controlling the OD of the fermentation liquor of the M16-1 strain₆₀₀>1.2。

Example 5

The embodiment provides M16-1 strain fermentation liquor, and the preparation method comprises the following steps:

s1, mixing 210g of potatoes, 14g of agar powder and 21g of cane sugar which are boiled and filtered by two layers of gauze, and fixing the volume to 1000mL by using purified water to obtain a PDA culture medium for later use; mixing 210g of potatoes which are boiled and filtered by two layers of gauze and 21g of cane sugar, and adding purified water to reach the volume of 1000mL to obtain a PDB culture medium for later use.

S2, inoculating the M16-1 strain stored on the filter paper sheet or the test tube inclined plane to the PDA culture medium for activation culture for 5 days, then picking out outer bacterial colony circle blocks by using an inoculating needle, putting the outer bacterial colony circle blocks into a culture bottle or a culture tank filled with the PDB culture medium for fermentation culture for 5 days, and obtaining M16-1 strain fermentation liquor after the bacterial liquid turns black; wherein the mass of the bacteria is about 16cm during fermentation culture²The temperature is controlled at 28 ℃, the oscillation speed is controlled at 180 rpm/min, and the OD of the fermentation liquor of the M16-1 strain is controlled₆₀₀>1.2。

Example 6

Firstly, healthy and plump susceptible rice Lijiang new-ball black cereals, monogenic rice lines with Lijiang new-ball black cereals as background, such as CO39(Pi-CO39), IRBL6(Pi-k), IRBL20(Pi-5(t)) and CLOLP KT (Pi-4a) seeds are selected, soaked in 70% alcohol for 40s, sterilized in 20% sodium hypochlorite solution for 40min, washed with sterile water for 5 times, germinated and grown at 28 ℃, and sowed in a 96-hole seedling raising plate when the sprouts grow to about 1 cm. After planting for about 25 days, the rice grows to three leaves and one heart, the M16-1 strain fermentation liquid provided by the above example 1 is sprayed on three-leaf and one-heart seedlings of the susceptible rice Lijiang Xingang Hei valley, and spore suspensions (with spore concentration of 4X 10 to obtain 4X 10 spore suspension) of the strongly pathogenic rice blast strains A7203-9 and A7203-8 are respectively sprayed and inoculated 72 hours after spraying⁵one/mL) of the test pieces, and strong pathogenic rice blast A7203-9 spore solutions were inoculated by spraying 72 hours after respectively spraying sterile water, and strong pathogenic rice blast A7203-8 spore solutions were inoculated by spraying 72 hours after spraying sterile water as a control. The incubation was carried out at 26C and 95% relative humidity in the dark for 24 hours. Then keeping the temperature and humidity constant, and irradiating for 12 hoursThe disease was investigated after 12 hours of alternate dark incubation for 7 days. The contrast of spraying water 72 hours before the inoculation of pathogenic bacteria is serious, the lesion area of the seedling sprayed with the M16-1 strain fermentation liquor is obviously reduced, and the disease condition is obviously relieved, as shown in the specific figure 1.

In addition, the M16-1 strain fermentation broth provided in example 1 was sprayed to monogenic rice lines CO39(Pi-CO39), IRBL6(Pi-k), IRBL20(Pi-5(t)), and CLOLPKT (Pi-4a) three-leaf one-heart seedlings against the black valley background of the susceptible rice Lijiang New Cluster, and spore suspensions (concentration: 4X 10) of spores of the strongly pathogenic rice blast strains A7203-9 and A7203-8 were inoculated by spraying 72 hours after spraying, respectively⁵one/mL) of the test solution, and the strong pathogenic rice blast A7203-9 spore solution sprayed and inoculated 72 hours after the spraying of the sterile water and the strong pathogenic rice blast A7203-8 spore solution sprayed and inoculated 72 hours after the spraying of the sterile water are respectively used as controls. The incubation was carried out at 26 ℃ and a relative humidity of 95% in the dark for 24 hours. Then, the disease condition was investigated after keeping the temperature and humidity constant and alternate incubation for 12 hours of light and 12 hours of dark for 7 days. The contrast of spraying water 72 hours before the inoculation of pathogenic bacteria causes severe disease, while the disease of rice seedlings sprayed with the M16-1 strain fermentation liquor is light, which shows that the nontoxic M16-1 strain fermentation liquor can effectively prevent and control the occurrence of rice blast in the seedling stage of rice and reduce the disease of the rice blast, and is shown in figure 2.

Example 7

Roping county is one of the major rice production areas in Yunnan province, and rice blast is serious all the year round. In the summer of 2020, in Luo Ping sheep village in Luo Ping county, Qujing city, Yunnan province, a random block design is adopted, and the area of a cell is about 9m²And repeating the steps for 3 times (figure 3), and performing M16-1 strain fermentation liquor tillering flourishing-stage field leaf blast control effect tests on four rice materials of Chujing 27 (main cultivar in Yunnan rice production), Lijiang Xin group black rice and single gene systems IRBL11 and F128-1 thereof.

The specific embodiment is as follows: the experiment was 4 treatments: the culture medium is CK (natural environment growth control), M (respectively spraying the M16-1 strain fermentation liquor provided by the embodiment 1 once in the tillering stage), G (spraying and inoculating the GUY11 spore suspension liquid of the strong pathogenic bacteria once in the tillering stage), and M-G (spraying and inoculating the GUY11 spore suspension liquid of the strong pathogenic bacteria 72 hours after spraying the M16-1 strain fermentation liquor provided by the embodiment 1 in the tillering stageOnce). Each treatment was repeated 3 times for a total of 12 plots (as shown in a of fig. 3), each plot was planted with 4 rice materials (chu japonica 27, lijiang new group black valley, monogenic lines IRBL11 and F128-1), and each material was planted with 50 plants. Planting specification: the plants are planted in wide and narrow rows with row spacing of 20cm and spacing of 30cm between every two rows (as shown in B of figure 3). The application amount of the fermentation liquor of the M16-1 strain is 50L/mu, and the concentration of GUY11 spore liquid is 4 multiplied by 10⁵The amount of the fertilizer is 25L/mu.

And (3) the control effect evaluation standard is as follows: disease incidence investigation was performed 2 weeks after spraying GUY11 spore suspension. Grading the disease condition of the leaf plague according to the international standard of 0-5 grade: grade 0, no disease; grade 1, the disease spots are small and few, and the area of the disease spots accounts for less than 1% of the area of the leaves; 2, the disease spots are small and much, or large and little, and the area of the disease spots accounts for 1 to 5 percent of the area of the leaves; grade 3, the disease spots are large and more, and the area of the disease spots accounts for 5 to 10 percent of the area of the leaves; grade 4, large and much scabs, wherein the area of the scabs accounts for 10 to 50 percent of the area of the leaves; grade 5, the lesion area accounts for more than 50% of the leaf area, or the whole leaf will die. 10 plants were investigated for each rice material (2 plants were investigated for each 8 plants), the disease level of all leaves was counted, and the disease incidence and disease index were calculated. Incidence rate = number of leaves affected/total number of leaves investigated × 100. The disease index ∑ (number of onset of disease at each stage × representative value at each stage)/(total number of examined leaves × highest representative value) × 100.

The control effect of leaf blast in tillering stage is shown in table 1: compared with the treatment of spraying the M16-1 strain fermentation liquor (M) once in the tillering stage, the (CK) under the field natural growth condition can effectively reduce the incidence rate and disease index of the field leaf blast under the natural condition by spraying the fermentation liquor once in the tillering stage, and the prevention effect reaches 46.2-56.7%; compared with the pathogenic bacteria GUY11 spore suspension (treated by G) sprayed and inoculated in the tillering stage under the condition of natural growth in a field, the pathogenic bacteria GUY11 spore suspension (treated by G) is sprayed and inoculated 72 hours after the M16-1 strain fermentation liquor is sprayed and inoculated in the tillering stage, the pathogenic bacteria GUY11 spore suspension (treated by M-G) is sprayed and inoculated 72 hours before the blast fungus is inoculated, the M16-1 strain fermentation liquor is sprayed and inoculated, the infection of the pathogenic bacteria in the tillering stage on rice can be effectively reduced, and the control effect reaches 50.1. Meanwhile, the larger the strength of pathogenic bacteria in the field is, the better the disease prevention effect of the M16-1 strain fermentation liquor is.

TABLE 1

In table 1, CK: the disease condition under the natural growth condition in the field; m: spraying M16-1 strain fermentation liquor for one time in the tillering stage of CK; g: spraying and inoculating a pathogenic bacteria GUY11 spore suspension once in a tillering stage under a field natural growth condition; M-G: compared with the G treatment, the M16-1 strain fermentation liquor is sprayed once in the tillering stage for 72 hours, and then the pathogenic bacteria GUY11 spore suspension is sprayed and inoculated once. Significance analysis used the least-squares (LSD), the numerical value being the mean soil standard error, with different lower case letters indicating the significance of the difference (p < 0.05).

Example 8

In the summer of 2020, in Luo Ping sheep village in Luo Ping county, Qujing city, Yunnan province, a random block design is adopted, and the area of a cell is about 9m²And repeating the steps for 3 times (figure 3), and performing M16-1 strain fermentation field neck blast control effect tests on four rice materials of Chujing 27 (main cultivar in Yunnan rice production), Lijiang Xinjiang Heiguan black rice and single gene systems IRBL11 and F128-1 thereof.

The specific embodiment is as follows: the experiment was 4 treatments: the culture medium is CK (natural environment growth control), M (M16-1 strain fermentation liquor provided by example 1 is sprayed once in the booting stage), G (GUY 11 spore suspension liquid for strong pathogenic bacteria is sprayed and inoculated once in the booting stage), and M-G (GUY 11 spore suspension liquid for strong pathogenic bacteria is sprayed and inoculated once 72h after the M16-1 fermentation liquor provided by example 1 is sprayed and inoculated in the booting stage). Each treatment was repeated 3 times for a total of 12 plots (as shown in a of fig. 3), each plot was planted with 4 rice materials (chu japonica 27, lijiang new group black valley, monogenic lines IRBL11 and F128-1), and each material was planted with 50 plants. Planting specification: the plants are planted in wide and narrow rows with row spacing of 20cm and spacing of 30cm between every two rows (as shown in B of figure 3). The application amount of the fermentation liquor of the M16-1 strain is 50L/mu, and the concentration of GUY11 spore liquid is 4 multiplied by 10⁵The amount of the fertilizer is 25L/mu.

And (3) the control effect evaluation standard is as follows: the onset of neck blast was investigated 1 week before harvest. Grading the neck blast disease condition according to the international standard of 0-5 grade: grade 0, no disease; grade 1, attack of individual branches and stalks; grade 2, about 1/3 branch and peduncle diseases; grade 3, the neck or main axis of the ear is attacked; grade 4, panicle neck attack, most blighted grains; grade 5, the development of the neck of the ear causes the white ear. 20 rice plants are investigated for each rice material (4 rice plants are investigated every 4 rice plants), all the tillering neck blast disease grades are counted, and the disease incidence and disease index are calculated. The incidence of disease is the number of diseased ears/total number of ears investigated x 100. The disease index ∑ (number of onset at each stage × representative value at each stage)/(total number of examined ears × highest representative value) × 100.

The control effect of the neck blast in the mature period is shown in table 2: compared with the treatment of spraying M16-1 strain fermentation liquor (M) once in the booting stage under the condition of field natural growth (CK), the spraying of the fermentation liquor once in the booting stage can effectively reduce the morbidity and disease index of field neck blast under natural conditions, and the control effect reaches 43.9-51.6%; compared with the method that pathogenic bacteria GUY11 spore suspension is sprayed and inoculated in the booting stage (G treatment) under the condition of natural growth in the field, the pathogenic bacteria GUY11 spore suspension is sprayed and inoculated 72 hours after M16-1 strain fermentation liquor is sprayed in the booting stage (M-G treatment), the M16-1 strain fermentation liquor is sprayed 72 hours before the rice blast is inoculated, the occurrence of the neck blast in the mature stage can be effectively reduced, and the control effect reaches 49.3-53.6%. The larger the field pathogenic bacteria strength is, the better the disease prevention effect of the M16-1 strain fermentation liquor is.

TABLE 2

In table 2, CK: the disease condition under the natural growth condition in the field; m: spraying M16-1 strain fermentation liquor for one time in the tillering stage of CK; g: spraying and inoculating a pathogenic bacteria GUY11 spore suspension once in a tillering stage under a field natural growth condition; M-G: compared with the G treatment, the M16-1 strain fermentation liquor is sprayed once in the tillering stage for 72 hours, and then the pathogenic bacteria GUY11 spore suspension is sprayed and inoculated once. Significance analysis used the least-squares (LSD), the numerical value being the mean soil standard error, with different lower case letters indicating the significance of the difference (p < 0.05).

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (8)

1. A non-toxic rice blast strain for preventing and controlling rice blast is characterized in that the non-toxic rice blast strain is named as rice blast bacteriumMagnaportheoryzaeM16-1 with the preservation number of CCTCC NO: M2020677.

2. The use of the non-toxic Pyricularia oryzae as claimed in claim 1 for controlling Pyricularia oryzae.

3. A non-toxic magnaporthe grisea fermentation broth for preventing and controlling rice blast is characterized in that the preparation method of the fermentation broth comprises the following steps:

inoculating the non-toxic pyricularia oryzae as defined in claim 1 onto a PDA culture medium for activation culture, and then inoculating onto a PDB culture medium for fermentation culture to obtain the fermentation broth.

4. The non-toxic Pyricularia oryzae fermentation broth for controlling Pyricularia oryzae according to claim 3, wherein the PDA culture medium comprises the following components per liter: 180-220 g of potatoes, 10-15 g of agar powder and 18-22 g of cane sugar.

5. The non-toxic Pyricularia oryzae fermentation broth for controlling Pyricularia oryzae according to claim 3, wherein each liter of the PDB culture medium comprises the following components: 180-220 g of potatoes and 18-22 g of cane sugar.

6. The non-toxic Pyricularia oryzae fermentation broth for controlling Pyricularia oryzae according to claim 3, wherein OD of the fermentation broth is₆₀₀＞1.2。

7. Use of a fermentation broth of Pyricularia oryzae as defined in any one of claims 3 to 6 for controlling Pyricularia oryzae.

8. The application of the magnaporthe grisea fermentation broth in preventing and controlling the magnaporthe grisea of rice as claimed in claim 7, wherein the application method of the magnaporthe grisea fermentation broth comprises the following steps:

and spraying the fermentation liquor of the rice blast fungi at the tillering stage and/or the pre-heading stage of the rice.

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