Coxsackie cocori qzb219 and application thereof

Abstract

The invention provides a Coxsackie cocori qzb219 strain and application thereof, the Coxsackie cocori qzb219 strain is named as Kosakonia cowaniiqzb219 in taxonomy, and the preservation number of the Coxsackie cocori qzb219 strain is CGMCC (China General Microbiological Culture Collection Center) NO.31519. The coxakella cocori has a good disease prevention effect on tobacco bacterial wilt and tobacco fusarium root rot, and can promote the growth of tobacco seedlings. The coxakella cocori qzb219 disclosed by the invention can be used for efficiently inhibiting the growth of ralstonia solanacearum and fusarium root rot of tobacco, has the activity of amylase and protease, and has the effect of promoting the growth of tobacco seedlings. The strain grows fast, is easy to ferment, and has good compatibility with current main bactericides thiediazole copper and zinc thiazole for preventing and controlling ralstonia solanacearum. The strain can effectively prevent and control tobacco bacterial wilt and tobacco fusarium root rot, has a certain growth promoting effect on tobacco seedlings, and is a biocontrol strain with great market potential.

Description

Technical Field

[0001] The invention relates to the technical field of microbiology, in particular to a strain of Cossackia cohnii QZB219 and application thereof. Background Art

[0002] Tobacco is an important cash crop, and my country is the country with the largest tobacco planting area and output in the world. At present, my country's tobacco planting areas are mainly concentrated in southern tobacco-growing areas such as Yunnan, Guizhou, and Sichuan. Root and stem diseases represented by tobacco bacterial wilt have caused great losses to tobacco production in these producing areas. In recent years, with the increase in temperature and rainfall in the north, tobacco root and stem diseases have become increasingly serious in my country's northern tobacco-growing areas. The pathogens of tobacco root and stem diseases can survive in tobacco field soil for a long time. Chemical pesticides are not very effective and can easily lead to increased resistance to pathogens. Their large-scale application also has adverse effects on biodiversity, human and animal health, and tobacco product safety. Therefore, the development of green, efficient, and pollution-free biological pesticides has become an important research direction for the prevention and control of tobacco root and stem diseases.

[0003] Microorganisms and their metabolites effectively inhibit the growth of pathogens, thereby controlling the occurrence of diseases. Currently, a variety of microbial agents have been used to prevent and control plant diseases. For rhizomes and stem diseases such as tobacco bacterial wilt and tobacco Fusarium wilt, most of the microbial agents currently developed are Bacillus.

[0004] At present, most commercial microbial agents have problems such as single source of strains, short effective period, high fermentation cost, insufficient concentration of active bacteria, poor compatibility with chemical pesticides and unstable prevention effect. It is urgent to further explore the antagonistic microbial resources in tobacco fields and develop efficient and green microbial agents on this basis to effectively control the occurrence of tobacco root and stem diseases. Summary of the invention

[0005] The present invention aims to provide a strain of Cossackia coli QZB219 and its application, the strain has strong antagonism against tobacco bacterial wilt pathogen and tobacco Fusarium root rot pathogen, fast growth rate, strong tolerance to fungicides, and has a certain growth-promoting effect on tobacco seedlings. The bacterial agent prepared by the strain has a high concentration of live bacteria, can effectively inhibit the growth of tobacco bacterial wilt pathogen and tobacco Fusarium root rot pathogen, and promote the growth of tobacco seedlings.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: In a first aspect of the present invention, a strain of Cossackia coli ( Kosakonia cowanii )qzb219, the coxsackie spp. ( Kosakonia cowanii )The deposit number of qzb219 is: CGMCC NO.31519.

[0007] In a second aspect of the present invention, a fermentation agent is provided, the fermentation agent comprising: Fermentation culture of Cossackia cohnii qzb219 to obtain a fermentation liquid or bacterial suspension; Or the fermentation liquid is spray-dried to obtain a dry powder bacterial agent.

[0008] Furthermore, the method for preparing the fermentation broth comprises: The Cossackia cohnii qzb219 is inoculated into a liquid culture medium for fermentation to obtain a fermentation liquid.

[0009] Furthermore, the fermentation culture conditions include: temperature of 26-30°C and pH of 5-9.

[0010] Furthermore, the concentration of Cossackia coli QZB219 in the bacterial agent is 1-10×10 9 CFU / mL.

[0011] In the third aspect of the present invention, provided is the use of the Cossackia cohnii qzb219 in inhibiting tobacco bacterial wilt pathogen and tobacco Fusarium solani root rot pathogen.

[0012] In the application, the concentration of Cossackia coli QZB219 is 1-10×10 6 CFU / mL.

[0013] In the fourth aspect of the present invention, there is provided the use of the fermentation bacteria agent in inhibiting tobacco bacterial wilt pathogen and tobacco Fusarium root rot pathogen.

[0014] In the fifth aspect of the present invention, provided is the use of Cossackia cohnii qzb219 in promoting the growth of tobacco seedlings.

[0015] In the sixth aspect of the present invention, there is provided the use of the fermentation bacteria agent in promoting the growth of tobacco seedlings.

[0016] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: Compared with the prior art, the Cossackia coli QZB219 provided by the present invention is a biocontrol bacterium different from conventional Bacillus, and the bacterium has a good antagonistic effect on tobacco bacterial wilt and tobacco Fusarium root rot, which are serious hazards in current production, and can effectively prevent and control tobacco bacterial wilt and tobacco Fusarium root rot. In addition, the bacterium grows fast, is easy to ferment, has good compatibility with the current main fungicide for preventing and controlling tobacco bacterial wilt, and can significantly promote the growth of tobacco seedlings, and has great potential for development into a highly effective biocontrol agent. In addition, the use of Cossackia coli QZB219 in combination with pesticides can reduce the application amount of pesticides thiophanate-copper and thiazole zinc (reduced by 15%-20%), and the prevention effect of tobacco bacterial wilt is increased by 30%, and the combination with pesticides has a synergistic effect.

[0017] The deposit date of the Cossackia coli qzb219 of the present invention is August 1, 2024, and the deposit number is CGMCCNO.31519. Its classification name is Cossackia coli Kosakonia cowanii The name of the depository is the General Microbiology Center of China Microbiological Culture Collection Administration, and the address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is the colony morphology of Coxsackia coli qzb219; Figure 2 This is the phylogenetic tree of Cossackia cohnii qzb219 based on 16S rDNA sequence; Figure 3 The inhibitory effect of Cossackia cohnii qzb219 on tobacco bacterial wilt pathogen; Figure 4 The inhibitory effect of Cossackia cohnii qzb219 on tobacco Fusarium root rot; Figure 5 It is the starch degradation effect of Cossackia coli qzb219; Figure 6 It is a protein degradation agent of Cossackia coli qzb219; Figure 7 is the growth curve of Cossackia cohnii qzb219; Figure 8 The control effect of Cossackia cohnii qzb219 on tobacco bacterial wilt, A is the diseased control plant; B is the qzb219-treated plant; Fig. 9 This is the growth-promoting effect of Coxsackievirus qzb219 on tobacco seedlings. A is the plant treated with qzb219; B is the control plant. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0021] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0022] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or obtained by existing methods.

[0023] The tobacco wilt pathogen Ralstonia solanacearum of the present application is provided by the Natural Product Pesticide Research Laboratory of the College of Plant Protection, Southwest University.

[0024] The tobacco Fusarium root rot fungus Fusarium solani of the present application is isolated from tobacco field soil.

[0025] The technical solution of the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows: The inventors of the present application collected rhizosphere soil from tobacco plants with severe tobacco wilt in Baoshan, Yunnan. Through separation, purification and screening, a bacterial strain was obtained and found to have an antagonistic effect on Fusarium oxysporum of tobacco. The bacterial strain was analyzed by colony morphology, biochemistry and 16S rRNA sequencing, and the strain was different from Cossackia corynae ( Kosakonia cowanii ) The homology of multiple strains was above 96%. Combined with physiological and biochemical characteristics, it was preliminarily determined that the strain belonged to ( Kosakonia cowani ), and named it Coxsackie spp. Kosakonia cowanii ).

[0026] The Cossackia cohnii of the present invention has a good promoting effect on the germination and growth of tobacco seeds and a good disease prevention effect on tobacco root rot, thus providing a theoretical basis for the subsequent development of biological microbial agents.

[0027] The following will describe in detail a strain of Cossackia coli qzb219 and its application in conjunction with examples and experimental data.

[0028] Example 1: Isolation, purification and identification of Cossackia coli qzb219 1. Isolation and purification of tobacco field soil microorganisms The culture medium used in the following examples of the present invention is as follows: LB medium: Dissolve 10 g of peptone, 5 g of yeast extract and 10 g of sodium chloride in 900 mL of water. For solid medium, add 10 g of agar powder and make the volume up to 1000 mL. Sterilize with high pressure steam at 121°C for 15-20 min.

[0029] PDA medium and Gao's medium No. 1 were purchased from Qingdao Haibo Biotechnology Co., Ltd.

[0030] 1.1 Isolation of antagonistic strains The soil samples were collected from the rhizosphere soil of diseased tobacco plants in tobacco fields in Baoshan, Yunnan, where tobacco bacterial wilt was severely infested.

[0031] Weigh 10 g of soil sample and add it to a conical flask containing 90 mL of sterile water. After sealing with a sealing film, enrichment culture was carried out at 30 °C and 180 r / min for 1 day. The mother solution after activation of tobacco rhizosphere soil was diluted in a gradient manner and evenly spread on LB medium plates, PDA medium plates and Gao's No. 1 medium plates to obtain a dilution of 10 -3 , 10 -4 , 10 -5 , 10 -6 and 10 -7 100 μL of dilution was added, and 3 plates were prepared for each dilution. The coated plates were placed in a 28°C constant temperature incubator for 48 h. At 24 and 48 h, the growth of the colonies on the culture medium was observed and recorded. A single colony was picked up with an inoculation needle and streaked on a new culture medium for culture and purification. A total of 387 strains were isolated.

[0032] 1.2 Screening of antagonistic bacteria Take a single colony of tobacco bacterial wilt pathogen and place it in 100mL of LB liquid culture medium, and activate it in a floor-standing constant temperature oscillator at 28℃ and 180 rpm for 48h. Take 100μL of the activated tobacco bacterial wilt pathogen suspension and evenly spread it on the solid culture medium to prepare a plate containing tobacco bacterial wilt pathogen. Punch holes at 25mm from the center of the edge of the plate (hole diameter is 5mm), and the number of holes on each plate is 6. Use a pipette to draw 35μL of candidate strain bacterial solution into the hole, and the blank LB liquid culture medium is used as a control. After the plate fully absorbs the bacterial solution, seal it and place it in a constant temperature incubator at 28℃ for culture. Observe and record the growth of the colonies on the plate and the antibacterial effect after 24h and 48h, respectively. The diameter of the antibacterial circle is measured by the cross method. Each treatment is repeated 3 times and the average value is taken.

[0033] A total of 102 strains with antagonistic effects on tobacco bacterial wilt pathogen were screened out from 387 strains, and the diameter of their inhibition zone ranged from 6.17mm to 29.5mm.

[0034] 1.3 Antagonistic bacteria rescreening The 102 antagonistic strains screened in the initial screening were subjected to antagonistic tests again using the inhibition zone method to confirm their antagonistic effects. Holes (hole diameter of 5 mm) were punched at 25 mm from the edge of the rescreening plate, and the number of holes punched on each plate was 3. The rest of the operations were the same as the initial screening. The rescreening screened 74 antagonistic strains that had inhibitory effects on tobacco bacterial wilt pathogens from the 102 antagonistic strains, and the diameter of their inhibition zones ranged from 8.5 mm to 38.5 mm.

[0035] The strain qzb219 had a stable antibacterial effect, with the diameters of the primary and secondary screening inhibition zones being 29.2 mm and 38.5 mm, respectively. It had a good antagonistic effect against tobacco bacterial wilt pathogen, and pure colonies of the strain qzb219 were obtained after multiple streaking purifications.

[0036] 2. Identification of qzb219 strain The colonies of qzb219 strain on LB medium are round, light yellow, with smooth and slightly shiny surface without wrinkles, moist, opaque, and regular edges ( Figure 1 ).

[0037] The DNA of strain qzb219 was used as a template, and the bacterial 16S rDNA universal primers were used to amplify the 16S rDNA gene fragment, and the amplified product was sent to Shanghai Bioengineering Co., Ltd. for sequencing. The amplification primers are: 27F (SEQ ID NO.1): 5'-AGAGTTTGATCCTGGCTCAG-3', 1492R (SEQ ID NO.2): 5'-GGTTACCTTGTTACGACTT-3'.

[0038] The PCR amplification system (20 μL) was as follows: 2× Taq Master Mix 10 μL; upstream and downstream primers 0.5 μL each; template DNA 1 μL; ddH 2 Add 0.1% HO to make up to 20 μL.

[0039] PCR amplification conditions were as follows: pre-denaturation at 94°C for 5 min; denaturation at 94°C for 40 s, annealing at 55°C for 50 s, and extension at 72°C for 60 s, for 35 cycles; and extension at 72°C for another 10 min.

[0040] The sequencing results are shown in SEQ ID NO. 3.

[0041] SEQ ID NO. 3:

[0042] The obtained 16S rDNA sequence was compared with the NCBI database by BLAST homology. The sequence similarity between the strain and Kosakonia cowanii exceeded 99%, which showed a high degree of homology. The strain was analyzed using the software MEGA 7 to determine its taxonomic status, and a phylogenetic tree was constructed using the MEGA software ( Figure 2 ), strain qzb219 and Kosakonia cowanii formed a branch.

[0043] Combined with the colony morphology and molecular biological analysis, the strain qzb219 was identified as Kosakonia cowanii and named Kosakonia cowanii qzb219. The strain was deposited in the China Center for Type Microorganism Collection on August 1, 2024, with the deposit number CGMCC No.31519; the deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing.

[0044] Example 2: Inhibitory effect of Cossackia cohnii QZB219 on tobacco bacterial wilt pathogen A plate containing tobacco bacterial wilt pathogen was prepared according to the method described in Example 1. A hole (hole diameter was 5 mm) was punched at 25 mm from the center of the edge of the plate. The number of holes punched on each plate was 3, and each hole was used as a replicate. The activated bacterial solution was inoculated into the hole with a sample volume of 35 μL. After constant temperature cultivation at 28°C for 48 h, the diameter of the inhibition zone was measured and the inhibition rate was calculated.

[0045] Inhibition rate (%) = (diameter of inhibition zone - diameter of spot hole) / diameter of inhibition zone × 100%.

[0046] The results of the antibacterial test were as follows Figure 3 As shown, the diameters of the three repeated inhibition zones were 30.2 mm, 30.5 mm and 30.3 mm, respectively. The calculated inhibition rate of Coxsackievirus qzb219 against tobacco bacterial wilt pathogen was 83.52%.

[0047] Example 3: Inhibitory effect of Cossackia coli QZB219 on tobacco Fusarium root rot pathogen A 5 mm diameter tobacco Fusarium root rot fungus cake was placed in the center of the culture medium. 8 μL of activated bacterial solution was inoculated on one side 25 mm away from the fungus cake, and the other side was not inoculated with bacterial solution as a control. This was repeated three times. After constant temperature culture at 28°C for 120 h, the radius of tobacco Fusarium root rot fungi was measured and the inhibition rate was calculated.

[0048] Inhibition rate (%) = (control colony radius - treated colony radius) / control colony radius × 100%.

[0049] The results of the antibacterial test were as follows Figure 4 As shown, the calculated inhibition rate of Cossackia coli QZB219 against tobacco Fusarium root rot pathogen was 65.21%.

[0050] Example 4. Hydrolase activity of Cossackia cohnii qzb219 The activated qzb219 bacterial solution was inoculated onto the starch screening medium to observe whether a transparent circle was produced to determine whether it had starch hydrolyzing enzyme activity. Figure 5 As shown, Coxsackieae qzb219 can degrade starch.

[0051] The activated qzb219 bacterial solution was spotted onto the casein screening medium. The appearance of a transparent circle on the plate indicated that the strain had the ability to degrade protein. Figure 6 As shown, Coxsackie japonicus QZB219 can degrade proteins.

[0052] In summary, Coxsackieae qzb219 can secrete proteases, amylases and other enzymes to degrade biological macromolecules, has strong metabolic activity, is easy to ferment and culture in large quantities, and is also conducive to its colonization in the soil and the role of biocontrol.

[0053] Example 5. Growth curve of Cossackia coli qzb219 The activated qzb219 bacterial solution was inoculated into LB medium at a 0.05% inoculum, and cultured at 28°C and 180 rpm. Samples were taken at 0, 2, 4, 6, 8, 10, 11, 12, 13, 15, 17, 19, 21, 23, 25, and 36 hours to measure the OD600 absorbance and draw a growth curve. Figure 7 As shown in the figure, the growth curve of qzb219 strain is an S-shaped growth curve, with slow growth in the first 6 hours, and then entering the exponential growth stage. It still shows a growth trend at 13 hours, but the growth rate is relatively slow, reaching a peak at 25 hours, and then begins to decrease. Considering the production cost comprehensively, the production of bacterial agent can be completed after 18-20 hours of cultivation.

[0054] Example 6: Bactericide compatibility of Cossackia coli QZB219 Thiophanate copper, thiazole zinc and other fungicides mainly used in production to control tobacco bacterial wilt were selected as test agents. The fungicides were diluted 300 times to prepare a high-concentration drug-containing LB liquid culture medium, which exceeded the recommended maximum application concentration of each fungicide. The control was an LB culture medium with sterile water. The activated qzb219 bacterial solution was inoculated into the LB culture medium at a 0.1% inoculation rate, and cultured at 28°C and 180 rpm for 18 h. The gradient dilution method was used to calculate the bacterial content of each treatment and the control to determine its compatibility with the fungicide.

[0055] Table 1 Compatibility of Coxsackievirus qzb219 with different drugs Fungicide name Manufacturer Drug concentration in culture medium (mg / ) Number of viable bacteria (CFU / mL) Sterile water control - - <![CDATA[3.07×10 9 ]]> 20% Thiophanate copper suspension Zhejiang Longwan Chemical Co., Ltd. 666.6 <![CDATA[50.2×10 9 ]]> 20% Thiazole zinc suspension Thiazole zinc Zhejiang Xinnong Chemical Co., Ltd. 666.6 <![CDATA[4.12×10 8 ]]> 5% Allicin Microemulsion Chengdu New Chaoyang Crop Science Co., Ltd. 166.7 <![CDATA[2.75×10 5 ]]> 10% Kasugamycin Soluble Granules Shaanxi Meibang Pharmaceutical Group Co., Ltd. 333.3 0 As shown in Table 1, Cossackia coli QZB219 has good compatibility with the main fungicides thiophanate-copper and thiophanate-zinc for the prevention and control of tobacco bacterial wilt in Yunnan tobacco-growing areas. High concentrations of thiophanate-copper slightly inhibit the growth of Cossackia coli QZB219; high concentrations of thiophanate-copper not only have no inhibitory effect on the growth of QZB219 strains, but its viable bacteria concentration is even higher than that of the control, which promotes the growth of QZB219 strains. The tested agents allicin and kasugamycin have an inhibitory effect on the growth of QZB219. Therefore, Cossackia coli QZB219 has good compatibility with the main fungicides thiophanate-copper and thiophanate-zinc for tobacco bacterial wilt. The use of fungicides does not affect the use of QZB219, and it can be used in combination with fungicides to increase the prevention effect.

[0056] Example 7: Control effect of Cossackia cohnii QZB219 on tobacco bacterial wilt and tobacco Fusarium root rot When tobacco seedlings had 4-5 true leaves, they were transplanted from seedling trays to 15 cm diameter plastic pots filled with soil collected from tobacco fields in Baoshan tobacco area of ​​Yunnan Province where tobacco bacterial wilt was serious. Two days after transplanting, each tobacco seedling was inoculated with 5 mL of Coxsackia coli QZB219 solution (1×10 6 CFU / mL), and 5 mL of sterile water was applied to the control tobacco seedlings. Two days after inoculation with qzb219 bacterial solution, the lateral roots were cut with scissors at a distance of 1-2 cm from the tobacco plant, and then the bacterial solution of tobacco wilt pathogen (1×10 7 CFU / mL) or tobacco Fusarium root rot spore suspension (1×10 7 The treated and control tobacco seedlings were placed in an artificial climate box at 30°C, 85% relative humidity, and 12h light intensity, and the disease status of the plants was observed and recorded daily.

[0057] Five days after inoculation with tobacco bacterial wilt pathogen, stem necrosis and leaf wilting occurred in the control plants, but no disease was observed in the qzb219-treated plants ( Figure 8 ). Ten days after inoculation with tobacco bacterial wilt pathogen, the incidence of control plants was 65%, and the disease index was 43.3; the incidence of tobacco plants treated with qzb219 was 10%, and the disease index was 7.8, and the control effect on tobacco bacterial wilt pathogen was 82%.

[0058] Seven days after inoculation with tobacco Fusarium root rot, the control plants began to wilt, while the qzb219-treated tobacco plants did not develop the disease. Fourteen days after inoculation with tobacco Fusarium root rot, the incidence of the control plants was 45%, and the disease index was 35.3; the incidence of the qzb219-treated tobacco plants was 15%, and the disease index was 12.2, with a control effect of 65.4% on tobacco Fusarium root rot. The application amount of the pesticides thiophanate-copper and thiazole zinc can be reduced (reduced by 15%-20%), and the control effect of tobacco bacterial wilt can be increased by 30%.

[0059] Example 8: Cossackia cohnii QZB219 promotes tobacco seedling growth Tobacco seeds were sown in seedling trays and transplanted to 14 cm diameter pots when they grew to 3-4 true leaves. Two days after transplanting, the roots were irrigated with QZB219 solution (1×10 6 CFU / mL) 5mL, blank medium was diluted according to the ratio of inoculation as control, each plant was used as a replicate, and 30 plants were treated and controlled. After inoculation, tobacco seedlings were placed in an artificial climate box at 30℃, relative humidity 85%, and light for 12h for cultivation.

[0060] Table 2 Effects of Coxsackia cohnii qzb219 on tobacco seedling growth Experimental treatment Number of blades Plant height (cm) Leaf fresh weight (g) Stem fresh weight (g) Root fresh weight (g) Plant fresh weight (g) Comparison 4.6±0.24 10.15±0.41 3.58±0.38 0.88±0.15 0.37±0.03 4.99±0.63 qzb219 5.8±0.20 11.13±0.63 6.01±0.40 1.24±0.83 0.58±0.05 7.83±0.38 25 days after inoculation, the treated plants grew vigorously and the growth was uniform among the plants, while the control plants were thin and weak and the growth was uneven ( Fig. 9 ). The average plant height, leaf number, and leaf, root, and plant fresh weight of tobacco seedlings treated with qzb219 were significantly higher than those of the control (p < 0.05), and the average stem fresh weight was also higher than that of the control (p = 0.19), indicating that root irrigation with Cossackia coli qzb219 can significantly promote the growth of tobacco seedlings.

[0061] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

[0062] Finally, it should be noted that the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article, or apparatus.

[0063] Although the embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the embodiments and all changes and modifications falling within the scope of the present invention.

[0064] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A strain of Cossackia coli qzb219, characterized in that The taxonomic name of Cossackia coli Kosakonia cowanii qzb219, its deposit number is: CGMCC NO.31519.

2. Use of the Cossackia cohnii qzb219 according to claim 1 in inhibiting tobacco bacterial wilt pathogen or tobacco Fusarium wilt pathogen.

3. Use of the Cossackia cohnii qzb219 according to claim 1 in promoting the growth of tobacco seedlings.

4. A fermentation agent, characterized in that: The fermentation agent comprises: A fermentation broth or bacterial suspension obtained by fermenting the Cossackia cohnii qzb219 according to claim 1; Or the fermentation liquid is spray-dried to obtain a dry powder bacterial agent.

5. The fermentation agent according to claim 4, characterized in that: The preparation method of the fermentation broth comprises: The Cossackia cohnii qzb219 is inoculated into a liquid culture medium for fermentation to obtain a fermentation liquid.

6. The fermentation agent according to claim 5, characterized in that: The fermentation culture conditions include: temperature of 26-30° C. and pH of 5-9.

7. Use of the fermentation agent according to any one of claims 4 to 6 in inhibiting tobacco bacterial wilt pathogen or tobacco Fusarium root rot pathogen.

8. Use of the fermentation agent according to any one of claims 4 to 6 in promoting the growth of tobacco seedlings.

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