CN112493252B - Sphingomonas cucurbitae and application of fermentation product thereof in preventing and treating rice bacterial diseases - Google Patents

Abstract

The invention discloses application of sphingomonas citrullini and a fermentation product thereof in preventing and treating rice bacterial diseases. The method specifically comprises the following steps: the application of the sphingomonas cucurbitae and the fermentation product thereof in preparing biological control medicaments for controlling rice bacterial diseases, the application of the sphingomonas cucurbitae and the fermentation product thereof in preparing bacteriostatic agents and the like. By applying the sphingomonas cucurbitae and the fermentation product thereof in rice planting, the development of diseases that various pathogenic bacteria infect rice can be effectively inhibited, and different treatment modes achieve ideal prevention and treatment effects. Meanwhile, the sphingomonas cucurbitae and the fermentation product thereof can play a role in promoting the growth of rice without diseases.

Description

Application of Sphingomonas cucurbita and its fermentation products in the control of rice bacterial diseases

technical field

The invention relates to the technical field of rice disease prevention and control, in particular to the application of Sphingomonas cucurbita and its fermentation products in the prevention and control of rice bacterial diseases.

Background technique

At present, the main bacterial diseases of rice are as follows:

Bacterial blight of rice is a bacterial disease caused by the infection of Xanthomonas oryzaepv.oryzae, Xoo, and it is also a domestic quarantine object. After sowing, it invades through water holes and wounds in leaves, and spreads by wind, rain, dew, irrigation water and the movement of managers. The common typical symptoms at the adult stage are leaf edge type, as well as acute type, withering type, midrib type and yellowing type. Among them, deep water irrigation, flooding, cluster irrigation, flood irrigation, excessive nitrogen fertilizer, and excessive growth are all conducive to the occurrence of diseases. In particular, during the susceptible period, the booting period was the most susceptible, followed by the tillering period.

Rice bacterial leaf spot, also known as thin stripe disease and stripe disease, is caused by Xanthomonas oryzaepv.oryzicola, Xoc. Mainly damages leaves. The lesions were initially dark green water-soaked small spots, which soon expanded into dark green to yellow-brown thin stripes between the veins, and both ends of the lesions were infiltrating green. A large number of beaded yellow bacterial pus is often overflowed on the lesions, which are small gelatinous particles after drying. Bacterial spillage on bacterial blight spots is rare and uncommon, while bacterial streaks are often covered with small beads of bacterial fluid. When the disease is severe, the streaks merge into irregular yellow-brown to withered white spots, similar to those of bacterial blight, but many translucent streaks can be seen in the light. When the disease is severe, the leaves are curled, and the field is yellow-white.

The pathogen of rice bacterial base rot is Erwinia chrysanthemum maize pathogenic variety (Erwiniachrysanthemipv.zeae, Ecz). Rice tillering stage often produces water-soaked oval spots on the leaf sheaths near the soil surface of the stem bases, which gradually expand into irregular large spots with brown edges and withered white in the middle. When the leaf sheaths are peeled off, the root nodes turn black and brown, sometimes visible. Dark brown vertical strips, rotten root nodes, accompanied by stench, and leaves of the plant wither and turn yellow. At the jointing stage, the diseased leaves turn yellow from bottom to top, the edge of the leaf sheath near the water surface is brown, and the middle gray stripes are spotted, and the root nodes are discolored with foul odor.

Rice bacterial ear blight is a new species/soil-borne ear disease on the rise in recent years. According to research reports, Burkholderia plantarii (Bp), Burkholderia glumae (Bge), and Burkholderia gladioli (Bgi) are the main pathogens of the disease. The pathogenic bacteria can harm the seedlings in the seedling stage, showing symptoms of blight. Most of the infected grains at the ear stage were atrophied and deformed, some or all of which turned gray-white, yellow-brown or dark brown, but the cob was still green. Symptoms can be described as "green culm, green leaves, ear rot, and withered grain". The disease has been reported in 17 countries including Asia, Africa and the Americas.

At present, the pesticides on the market to prevent and control bacterial diseases mainly include inorganic copper, organic copper and thiazole, but there is no broad-spectrum biocontrol agent for preventing and controlling bacterial diseases of rice.

In view of this, the present invention is proposed.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide the application of cucurbit Sphingomonasmelonis (Sphingomonasmelonis, Sm) and its fermentation products in preventing and treating bacterial diseases of rice, so as to improve the above-mentioned technical problems.

The present invention is realized in this way:

In the first aspect, the present invention provides the application of Sphingomonas cucurbita and its fermentation products in preventing and treating bacterial diseases of rice.

In the second aspect, the present invention also provides the application of Sphingomonas cucurbita and its fermentation products in the preparation of biological control agents for preventing and treating bacterial diseases of rice.

In a third aspect, the present invention also provides a biological control agent for preventing and treating bacterial diseases of rice, which comprises a cucurbit Sphingomonas substance and an adjuvant, and the cucurbit Sphingomonas substance is Sphingomonas citrullus or the fermentation product of the sphingomonas citrullus, the auxiliary agent includes a solvent, a cosolvent, an emulsifier, a wetting agent, a dispersing agent, an adhesive and a stabilizer. at least one.

In a third aspect, the present invention also provides the application of Sphingomonas cucurbita and its fermentation products in the preparation of bacteriostatic agents.

The technical scheme of the present invention has the following beneficial effects: by applying Sphingomonas cucurbita and its fermented products in rice cultivation, the development of the disease caused by various pathogenic bacteria infecting rice can be effectively inhibited, and different treatment methods can achieve better control effect. At the same time, Sphingomonas cucurbita and its fermentation products can also play a role in promoting the growth of uninfected rice.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the control effect result of Sm bacteria and its fermentation product spraying method on rice bacterial leaf spot caused by Xoc;

Fig. 2 is the control effect result of Sm bacteria and its fermentation product spraying method on rice bacterial blight caused by Xoo;

Fig. 3 is the control effect result of Sm bacteria and its fermentation product spraying method on rice bacterial base rot caused by Ecz;

Fig. 4 is the control effect result of Sm bacteria and its fermented product spraying method on rice bacterial ear blight caused by Bp;

Fig. 5 is the control effect result of Sm bacteria and its fermentation product spraying method on rice bacterial ear blight caused by Bge;

Figure 6 shows the results of the control effect of Sm bacteria and its fermentation product spraying method on rice bacterial ear blight caused by Bgi.

Detailed ways

In order 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 described clearly and completely below. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

The application of Sphingomonas cucurbita and its fermentation product in preventing and treating bacterial diseases of rice will be specifically described below.

Some embodiments of the present invention provide the application of Sphingomonas cucurbita and its fermentation products in preventing and treating bacterial diseases of rice.

It should be noted that Sphingomonas cucurbita is an existing bacterial species determined by a nucleic acid sequence, and the application is not limited to the source of the bacterial species, and the source can be the bacterial species with the deposit number of CGMCC 1.15791. It can also be isolated from plants such as rice or from soil and water through experiments.

The fermentation product of Sphingomonas cucurbita can be obtained by the following steps:

The single colony of Sphingomonas cucurbita is pre-cultured in LB medium, and then the pre-cultured bacterial liquid is cultured in MA liquid medium; MA medium includes 200X inorganic salt solution, 8-12 g glucose and water 1L.

The inorganic salt solution is composed of: NH ₄ H ₂ PO ₄ 0.08wt%-0.12wt%, KCl 0.01wt%-0.03wt% and MgSO ₄ ·7H ₂ O 0.01wt%-0.03wt%, preferably the inorganic salt solution is composed of are: NH ₄ H ₂ PO ₄ 0.1 wt %, KCl 0.02 wt %, and MgSO ₄ ·7H ₂ O 0.02 wt %.

Specifically, a single colony of Sm was vertically picked with an inoculation needle, placed in 50 ml of LB medium for pre-cultivation, and after culturing for 24 hours, 10 mL of bacterial liquid was drawn, centrifuged at 5000 rpm for 5 min, and the supernatant was discarded. Wash with equal amount of clean water, shake and mix, then centrifuge at 5000 rpm for 5 minutes, add the same amount of clean water again, shake and mix, absorb 100 μL of the mixed bacterial liquid and add it to 60 mL of MA liquid medium for cultivation, the formula of MA liquid medium The ratio is inorganic salt solution (NH ₄ H ₂ PO ₄ 0.1%, KCl 0.02%, MgSO ₄ ·7H ₂ O 0.02%) 200X, glucose 10g, water 1L, after completion, the medium containing Sm was placed at 25°C for constant temperature shaking culture In one week, the fermentation broth of Sphingomonas cucurbita can be obtained.

The fermentation broth is then extracted to obtain the fermentation product of Sphingomonas cucurbita. In some embodiments, the extraction method adopts extraction agent or macroporous resin adsorption method (MR) for extraction; more preferably, the extraction agent is selected from dichloromethane (DCM), ethyl acetate (EtOAc) and petroleum ether (PE) at least one of. The polarity of these three organic solvents increases sequentially, and the polarity range is wide, which can ensure the extraction of the active secondary metabolites in the Sphingomonasmelonis fermentation broth. At the same time, the secondary metabolites of Sphingomonasmelonis were rapidly extracted by high-throughput macroporous resin adsorption (MR). Four types of Sphingomonasmelonis fermentation products were obtained based on different extraction methods of DCM, EtOAc, PE and MR.

Specifically, the bacterial diseases of rice controlled by Sphingomonas cucurbita and its fermented products include, but are not limited to, bacterial blight of rice, bacterial blight of rice, bacterial base rot of rice, and bacterial ear blight of rice One or more of the diseased ear blight.

Further, in some embodiments, the application of the above-mentioned prevention and control of bacterial diseases of rice is: soaking the rice seeds with the fermentation product of Sphingomonas cucurbita or Sphingomonas cucurbita.

In some embodiments, the soaking time is at least 10 hours. For example, 12 hours, 13 hours, or 14 hours, etc.

In order to achieve a better control effect, in some embodiments, the rice seeds are seeds that have been primed for germination.

In some embodiments, the application of the above-mentioned prevention and control of bacterial diseases of rice can also be: spraying Sphingomonas cucurbita or the fermentation product of Sphingomonas cucurbita to rice plants at different growth stages.

In some embodiments, the spraying of Sphingomonas cucurbita or the fermentation product of Sphingomonas cucurbita is performed at the tillering stage and the heading stage, respectively.

In order to enable the fermentation product of Sphingomonas cucurbita or Sphingomonas cucurbita to have a better control effect on rice, and to control the cost of use, in some embodiments, the rice plants are sprayed The inoculum concentration of Sphingomonas cucurbita is 10 ³ -10 ⁷ CFU/mL, such as 10 ³ CFU/mL, 10 ⁵ CFU/mL or 10 ⁷ CFU/mL, etc.; The pharmaceutical concentration of the fermentation product of Sphingomonas citrullus is 10-100 μg/mL, for example, 10 μg/mL, 50 μg/mL or 100 μg/mL.

Some embodiments of the present invention also provide the application of Sphingomonas cucurbita and its fermentation products in the preparation of biological control agents for preventing and treating bacterial diseases of rice. The Sphingomonas citrullus used in its application and its fermentation product are as described above, and will not be repeated here.

It should be noted that biological control agents include but are not limited to any one of powders, granules, suspensions, oils, fumigants, sustained release agents, seed coating agents, microcapsules, effervescent tablets and sprays . But the active ingredient in this biological control agent is Sm or its fermentation product, and the above biological control agent contains Sm preparation, which can be any one of the mixture of Sm cell, Sm fermentation product, Sm cell and fermentation product. They can also be combined with other compounds to form a compound formulation for controlling bacterial diseases of rice.

In some embodiments, the biological control agent is a control agent for controlling rice bacterial leaf spot, rice bacterial blight, rice bacterial base rot or rice bacterial ear blight.

Further, some embodiments of the present invention also provide a biological control agent for preventing and treating bacterial diseases of rice, which comprises a cucurbit Sphingomonas substance and an adjuvant, and a cucurbit Sphingomonas substance For Sm or its fermentation product, the adjuvant includes, but is not limited to, at least one of a solvent, a cosolvent, an emulsifier, a wetting agent, a dispersing agent, a sticking agent and a stabilizer.

Some embodiments of the present invention also provide the application of Sphingomonas cucurbita and its fermentation product in preparing a bacteriostatic agent.

Specifically, the bacteriostatic agent is a bacteriostatic agent that inhibits rice pathogenic bacteria. In some embodiments, the rice pathogen includes one or more of Xoo, Xoc, Ecz, Bp, Bge, and Bg.

The features and performances of the present invention will be further described in detail below in conjunction with the embodiments.

Example 1

This example provides the inhibitory effect of Sphingomonasmelonis fermentation products on rice pathogenic bacteria. The specific operations are:

1. Sphingomonasmelonis culture: The Sphingomonasmelonis (Sm) strain was routinely cultured in a constant temperature incubator at 25°C, and the selected medium was LB medium.

2. Preparation of Sm fermentation product: Pick a single colony of Sm vertically with an inoculating needle and place it in 50 mL of LB medium for pre-cultivation. After culturing for 24 hours, aspirate 10 ml of bacterial liquid, centrifuge at 5000 rpm for 5 min and discard the supernatant. Then add the same amount of clean water to wash, shake and mix, then centrifuge at 5000rpm for 5 minutes, add the same amount of clean water again, shake and mix, suck 100μL of the mixed bacterial solution and add it to 60mL MA liquid medium for culture, MA culture The formula ratio of the base is inorganic salt solution (NH ₄ H ₂ PO ₄ 0.1%, KCl 0.02%, MgSO ₄ 7H ₂ O 0.02%) 200X, glucose 10g, water 1L, after completion, put the medium containing Sm at 25°C Culture with constant temperature shaking for one week.

Four types of Sphingomonasmelonis fermentation products were obtained by four extraction methods: DCM, EtOAc, PE and MR.

3. Determination of antibacterial activity: the measurement of antibacterial activity refers to the broth microdilution method. Pick pathogenic bacteria colonies (Xoo, Xoc, Ecz, Bp, Bge, Bgi) from the daily culture solid medium, put them into sterilized Mueller-Hinton medium, and cultivate them at 25°C until partial turbidity, and then use a freshly placed The concentration of MH broth was corrected to 0.5 McFarland turbidity standard, and the bacterial content was 1～2×10 ⁸ CFU/mL, then diluted with MH broth at a ratio of 1:1000, and the diluted bacterial solution was transferred to 96 wells In the plate, 100 μL of bacterial solution was inoculated in each hole, and then 100 μL of Sm fermentation products and kasugamycin (positive control) of different mass concentrations were added respectively, so that the final concentrations were 256 mg/kg, 128 mg/kg, 64 mg/kg, 32 mg/kg, 16mg/kg, 8mg/kg, 4mg/kg, 2mg/kg, 1mg/kg, 0.5mg/kg, 0.25mg/kg, each plate is additionally set up without adding the blank control and adding the same amount of dimethyl sulfoxide. For the negative control, each group of treatment was repeated 3 times. After the treatment was completed, they were incubated at 25°C for 24 hours, and the minimum inhibitory concentration (MIC) of each Sm fermentation product against each pathogenic bacteria was observed and recorded.

The observed results are shown in Table 1-Table 6.

Table 1 MIC value of Sm fermentation product to Xoo

Table 2 MIC value of Sm fermentation product to Xoc

Table 3 MIC value of Sm fermentation product to Ecz

Table 4 MIC value of Sm fermentation product to Bp

Table 5 MIC value of Sm fermentation product to Bge

Table 6 MIC value of Sm fermentation product to Bgi

It can be seen from the results in Tables 1 to 6 that the Sm fermentation products exhibited different degrees of growth inhibition on common pathogenic bacteria in rice. Among them, the inhibitory effect of Sm fermentation products extracted by EtOAc and MR was stronger than that of fermentation products obtained by other extraction methods. In addition, the overall inhibitory effect of Sm fermentation products was the best for Xoc, followed by Xoo, Ecz, Bgi, Bge, and Bp.

Example 2

This example provides the control application of Sm bacteria and its fermentation products in rice growth substrates. The specific operations are:

1. Rice germination and pathogen inoculation treatment: put the rice seeds in a glass petri dish, add a small amount of water (subject to the surface of the seeds), and then cultivate in a 25°C constant temperature incubator, which needs to be replaced every other day Once clear water, after 2-3 days, the seeds appear white, and the germination is completed at this time. For the seeds after germination, Bp and Bge, which can cause disease at the seedling stage, were selected for inoculation treatment (10 ⁵ CFU/mL, 6 hours), and sterilized water was used as an uninfected blank control.

2. Control effect of Sm bacteria and its fermentation products on pathogenic bacteria-infected seedlings: in MS plant medium, add Sm bacteria (10 ³ , 10 ⁵ , 10 ⁷ CFU/mL) or Sm fermentation products (MR, 10, 50, 100 μg/mL), the same volume of sterilized water was used as a control, and 1.5% gellan gum was added to it to make it a solid medium, and each 20 mL was dispensed into culture flasks. The above inoculated Bp or Bgi and uninoculated germinated seeds were transplanted to the medium. 10 plants per bottle, put the culture bottle into a constant temperature incubator at 25°C, and cultivate the rice seedlings with 12 hours of light and 12 hours of darkness every day. Statistical Analysis. The results are shown in Table 7 and Table 8.

Table 7 Control effect of Sm bacteria and its fermentation product matrix supplementation on Bp-infected seedlings

deal with Seedling length (cm) Root length (cm) blank 4.3 1.5 +Bp 0.5^** 0.1^** +Sm cells (10³CFU/mL)+Bp 3.9 ^** 1.0^** +Sm cells (10⁵CFU/mL)+Bp 4.0^** 1.2 ^** +Sm cells (10⁷CFU/mL)+Bp 4.2 ^** 1.2 ^** +Sm fermentation product (10μg/mL)+Bp 3.0^** 1.3 ^** +Sm fermentation product (50μg/mL)+Bp 3.8 ^** 1.4 ^** +Sm fermentation product (100μg/mL)+Bp 4.1 ^** 1.4 ^** +Sm cells (10⁵CFU/mL) 4.7 ^** 1.8 ^**

where ^** P<0.001.

Table 8 Control effect of Sm bacteria and its fermentation product matrix supplementation on Bge-infected seedlings

Where, ^* P<0.005, ^** P<0.001.

It can be seen from Tables 7-8 that the supplementation of Sm bacteria and its fermentation products to the rice growth substrate has a significant control effect on both Bp and Bge infected seedlings. The seedlings inoculated with Bp or Bge showed obvious symptoms (yellowing and dwarfing), and the growth of shoots and roots were significantly inhibited (+Bp group vs. blank control); while the growth of seedlings supplemented with Sm bacteria and its fermentation products was significantly improved. In the seedlings infected with pathogenic bacteria, the symptoms of seedlings and roots were significantly relieved (Sm bacteria and its fermentation product treatment group vs. Bp group); in addition, compared with the blank control, the addition of Sm bacteria and its fermentation products can also promote the growth of rice to a certain extent effect.

Example 3

This example provides the control effect of Sm bacteria and its fermentation products in treating rice seeds. The specific operations are:

Rice germination refers to Example 2, the seeds after the germination is completed are treated with Sm bacteria (10 ³ , 10 ⁵ , 10 ⁷ CFU/mL) and Sm fermentation products (MR, 10, 50, 100 μg/mL) for 12 hours respectively. , sterilized water was used as blank control. Then, referring to Example 2, the treatment of pathogenic bacteria Bp or Bge, rice transplanting and symptom observation were carried out. The observed results are shown in Tables 9 and 10.

Table 9 Control effect of Sm bacteria and its fermentation product soaking on Bp-infected seedlings

where ^** P<0.001.

Table 10 Control effect of Sm bacteria and its fermentation products on seedlings infected with Bge

deal with Seedling length (cm) Root length (cm) blank 4.4 1.4 +Bge 1.0^** 0.5^** +Sm cells (10³CFU/mL)+Bge 2.9 ^** 0.7^** +Sm cells (10⁵CFU/mL)+Bge 3.5 ^** 1.1^** +Sm cells (10⁷CFU/mL)+Bge 4.0^** 1.2 ^** +Sm fermentation product (10μg/mL)+Bge 2.1 ^** 0.9^** +Sm fermentation product (50μg/mL)+Bge 3.0^** 1.0^** +Sm fermentation product (100μg/mL)+Bge 3.5 ^** 1.1^** +Sm cells (10⁵CFU/mL) 4.9 ^* 1.8 ^*

Among them, ^* P<0.005, ^* P<0.001.

From the results in Tables 9-10, it can be seen that the use of Sm bacteria and its fermentation product rice seeds for seed soaking treatment has significant control effects on both Bp and Bge infected seedlings. The seedlings inoculated with Bp or Bge showed obvious symptoms (yellowing and dwarfing), and the growth of shoots and roots were significantly inhibited (+Bp group vs. blank control); while the growth of seedlings supplemented with Sm bacteria and its fermentation products was significantly improved. In the seedlings infected with pathogenic bacteria, the symptoms of seedlings and roots were significantly relieved (Sm bacteria and its fermentation product treatment group compared with +Bp group); in addition, compared with the blank control, adding Sm bacteria and its fermentation products can also promote the growth of rice to a certain extent effect.

Example 4

This example provides the control effect of the rice spray method for spraying Sm bacteria and its fermentation products. The specific operations are:

For rice germination, refer to Example 2, the seeds after germination were cultured in MS plant medium for 2 weeks, and transplanted into rice planting barrels (35 cm in diameter, height) and placed in a greenhouse for cultivation (light period was 12 h in the dark). Cultivated to the tillering stage respectively and carried out Xoc, Xoo, Ecz to carry out the control effect test, after inoculation with pathogenic bacteria Xoc, Xoo, Ecz, sprayed Sm bacteria (10 ³ , 10 ⁵ , 10 ⁷ CFU/mL), Sm fermentation product (MR, 10 , 50, 100 μg/mL), sterile water (blank control), zinc thiazole (recommended dose, positive control). Another batch of rice was tested for Bge, Bgi and Bp control effects at heading stage. After inoculation with pathogenic bacteria Bge, Bgi and Bp, Sm bacteria (10 ³ , 10 ⁵ , 10 ⁷ CFU/mL) and Sm fermentation products (MR, 10, 50, 100 μg/mL). The control effect was characterized by collecting images of diseased leaves, stem bases, and panicles, and using OTSU to calculate the area rate (%) of diseased spots. The results are shown in Figures 1-6.

From the results in Figures 1 to 6, it can be seen that Sm bacteria and its fermentation products sprayed on rice plants at different growth stages have 45%-74% control effects on rice bacterial leaf streak caused by Xoc (Figure 1). It has 36%-75% control effect on rice bacterial blight (Figure 2), and has 42%-75% control effect on rice bacterial base rot caused by Ecz (Figure 3). Ear blight has 34% to 78% (Figures 4 to 6). Therefore, Sm bacteria and its fermentation products have application prospects in the preparation of rice bacterial diseases.

It should be noted that "103CFU/mL, 105CFU/mL, 107CFU/mL" in the abscissa in Figures 1 to 6 actually represent " ^103CFU /mL, ^105CFU /mL, ^107CFU /mL" in sequence .

In summary, Sm bacteria and its fermentation products can be used to prevent and treat bacterial diseases of rice, and can be mainly used to prepare biocontrol preparations for bacterial diseases of rice. The biocontrol preparation of the embodiment of the present invention is applied to rice planting, can promote the healthy growth of rice, and has good control effect in reducing rice blight, bacterial blight, bacterial leaf spot, ear blight, ear rot, etc. It can reduce the damage of rice ear diseases.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (18)

1. S. citrullinated unicellularSphingomonas melonisAnd the application of the fermentation product thereof in preventing and treating rice bacterial diseases, which is characterized in that the rice bacterial diseases comprise one or more of rice bacterial leaf streak, rice bacterial leaf blight, rice bacterial basal rot and rice bacterial ear blight.

2. The use according to claim 1, wherein the fermentation product of sphingomonas citrullinis produced by essentially the steps of:

pre-culturing the single colony of the sphingomonas citrullinis in an LB culture medium, and culturing a bacterial liquid obtained by pre-culturing in an MA liquid culture medium; the MA liquid culture medium comprises an inorganic salt solution 200X, glucose 8-12 g and water 1L, wherein the inorganic salt solution comprises the following components: NH (NH)₄H₂PO₄ 0.08wt%~0.12wt%、KCl 0.01wt%~0.03 wt%，MgSO₄·7H₂O 0.01wt%~0.03wt%；

And extracting the fermentation liquor to obtain a fermentation product of the citrullinated sphingomonas.

3. Use according to claim 2, characterized in that the inorganic salt solution consists of: NH (NH)₄H₂PO₄0.1wt%, KCl 0.02wt% and MgSO₄·7H₂O 0.02wt%。

4. The use of claim 2, wherein the extraction is carried out by using an extractant or a macroporous resin adsorption method.

5. The use according to claim 4, wherein the extractant is selected from at least one of dichloromethane, ethyl acetate and petroleum ether.

6. The use according to claim 2, wherein the sphingomonas cucurbitae is an endophyte of rice.

7. The use according to any one of claims 1 to 6, wherein the use is for seed soaking of rice seeds with the sphingomonas citrullini or the fermentation product of sphingomonas citrullini.

8. Use according to claim 7, wherein the seed soaking time is at least 10 hours.

9. The use according to claim 7, wherein the rice seed is a pregerminated seed.

10. The use according to any one of claims 1 to 6, wherein the use is spraying the sphingomonas citrullini or the fermentation product of sphingomonas citrullini on rice plants at different growth periods.

11. The use according to claim 10, characterized in that spraying the sphingomonas citrullini or the fermentation product of sphingomonas citrullini is performed in the tillering stage and the heading stage, respectively.

12. The use of claim 10, wherein the concentration of sphingomonas cucurbitae applied to rice plants is 10³~10⁷CFU/mL; the concentration of the agent of the fermentation product of the sphingomonas citrullini sprayed on the rice plants is 10-100 mug/mL.

13. The use according to claim 10, wherein said use is the addition of said sphingomonas citrullinoides or a fermentation product of said sphingomonas citrullinae to a rice growth substrate.

14. The use according to claim 10, wherein the sphingomonas citrullinis added in an amount of 10³~10⁷CFU/mL; the addition amount of the fermentation product of the sphingomonas citrullini is 10-100 mu g/mL.

15. The application of the sphingomonas cucurbitacearum and the fermentation product thereof in preparing the preventing and treating medicament for preventing and treating the rice bacterial diseases is characterized in that the rice bacterial diseases comprise one or more of rice bacterial leaf streak, rice bacterial leaf blight, rice bacterial basal rot and rice bacterial ear blight.

16. The use of claim 15, wherein the control agent comprises any one of a powder, a granule, a suspension, an oil, a fumigant, a sustained release agent, a seed coating, an effervescent tablet, and a spray.

17. The use of claim 16, wherein the sustained release agent comprises a microcapsule.

18. The application of the citrullinated unicellular bacterium and the fermentation product thereof in the preparation of the medicament for preventing and treating bacterial diseases is characterized in that the medicament for preventing and treating bacterial diseases is a medicament for inhibiting pathogenic bacteria of rice, and the pathogenic bacteria of rice comprise pathogenic varieties of rice of xanthomonasXanthomonas oryzae pv. oryzaeXanthomonas oryzae-oryza sativa pathogenic variantsXanthomonas oryzaepv. oryzicolaErwinia chrysanthemi maize pathogenic variantsErwinia chrysanthemipv. zeaeBurkholderia plantariiBurkholderia plantariiBurkholderia nodorumBurkholderia glumaeAnd Burkholderia gladioliBurkholderia gladioliOne or more of (a).

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