Strain with capability of degrading tomato straw as well as culture method and application of strain

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to a group of strains with degradation capability and a culture method and application thereof. According to the invention, four strains separated from tomato plants are found, the strains are XNTD-1, XNTD-2, XNCD-4 and XNTD-13, and the strains have a degradation effect on agricultural wastes and can be used for recycling the agricultural wastes. Fermentation liquor of the strain can effectively degrade tomato straw waste. The tomato straws are independently treated by the four strains, and the average value of the degradation rate of the tomato straws reaches 54.00%; the average hydrolysis value reaches 2.30; the average value of the cellulose degradation rate reaches 31.00%; compared with a water treatment control group, the effect is obviously improved. The weight loss ratio of the tomato straws treated by the compound bacteria is 56.03%, and is increased by 41.53% compared with that treated by CK. The strain disclosed by the invention is simple to prepare, low in cost, non-toxic, harmless and free of environmental pollution, is beneficial to safe and effective degradation of tomato straw wastes, and is also beneficial to environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, specifically relating to a group of strains capable of degrading tomato straw, their cultivation methods, and applications. Background Technology

[0002] Tomatoes are an important vegetable crop, with a global annual production of 170 million tons, ranking first among vegetable crops. my country consistently ranks first in the world in tomato production, with the tomato planting area increasing from 1.055 million hectares in 2017. 2 It increased year by year to 1,169,200 hectares in 2022. 2 The growth rate reached 10.82%, and it continues to rise (Xu Jing, Xiang Chaoyang, Liu Mei. Cost-benefit analysis and quality improvement and efficiency enhancement path of my country's tomato industry [J / OL]. China Vegetables, 2025).

[0003] Based on an average waste production coefficient of 0.36 for vegetables, the theoretical amount of tomato straw waste is 2.3 × 10⁻⁶. 7 This demonstrates the abundance of tomato straw resources (Zhang Feixue, Zhou Lili, Zhou Xiaoyu, et al. Research progress on resource utilization of tomato straw waste in my country [J]. Vegetables, 2023). However, currently, most tomato straw in my country is not fully utilized. It is often piled up haphazardly in fields to rot naturally, or discarded as waste, which easily breeds pests and diseases and causes environmental pollution. Therefore, the harmless treatment and resource utilization of tomato straw, and the realization of local utilization of straw waste, are urgent problems to be solved.

[0004] Straw, derived from crops, contains nitrogen, phosphorus, potassium, and various trace elements necessary for plant growth, making it an important source of organic fertilizer. According to relevant test results, tomato straw contains 37.64% organic matter, 1.79% total nitrogen, 0.36% total phosphorus, 1.98% total potassium, 27.2 mg / kg cellulose, 26.3 mg / kg lignin, and a C / N ratio of 20.98 (Yu Yalin, Hu Jing, Fan Zhaobo, et al. Effects of summer fumigation on mineralization and CO2 emissions of straw returned to the field in greenhouse vegetable fields [J]. Anhui Agricultural Sciences, 2020). However, the main components of straw are cellulose, hemicellulose, and lignin, which are difficult to decompose quickly. This is a key challenge limiting the transformation of straw into valuable resources. Currently, there are many methods for treating the main components of straw, including physical, chemical, and biodegradation. Biodegradation involves fermentation and enzymatic hydrolysis of straw by microorganisms. Compared with physical and chemical treatments, microbial treatment has no secondary pollution, is safer, and has low energy consumption, making it environmentally friendly and economical.

[0005] Therefore, finding efficient tomato straw-degrading bacteria has become an important way to solve this problem. Summary of the Invention

[0006] This invention discovered four strains isolated from tomato plants that have a degradation effect on agricultural waste, and based on this, the invention was completed.

[0007] In a first aspect, the present invention provides a group of strains selected from tomato plants that degrade tomato straw, said strains being selected from one or more of XNTD-1, XNTD-2, XNCD-4 and / or XNTD-13.

[0008] Furthermore, the XNTD-1 accession number is CGMCC NO. 34324, the accession name is XNTD-1, and the DNA sequence of the strain is shown in SEQ ID NO.1; the strain is classified and named as follows: Xenophilus sp. The strain was deposited on April 24, 2025; the deposit address of the strain is the China General Microbiological Culture Collection Center.

[0009] Furthermore, the XNTD-2 accession number is CGMCC NO. 34325, the accession name is XNTD-2, and the DNA sequence of the strain is shown in SEQ ID NO.2; the strain is classified as *Sphingosine monocytogenes*. Sphingobacterium sp. The strain was deposited on April 24, 2025; the deposit address of the strain is the China General Microbiological Culture Collection Center.

[0010] Furthermore, the XNCD-4 accession number is CGMCC NO. 34328, the accession name is XNCD-4, and the DNA sequence of the strain is shown in SEQ ID NO. 3; the strain is classified as Microbacterium. Microbacterium sp. The strain was deposited on April 24, 2025; the deposit address of the strain is the China General Microbiological Culture Collection Center.

[0011] Furthermore, the XNTD-13 strain has the accession number CGMCC NO. 34326 and the accession name XNTD-13. Its DNA sequence is shown in SEQ ID NO. 4. The strain is classified as *Oligotrophomonas*. Stenotrophomonas sp. The strain was deposited on April 24, 2025; the deposit address of the strain is the China General Microbiological Culture Collection Center.

[0012] In a second aspect, the present invention provides a method for screening strains as described in the first aspect of the present invention from tomato plants: S1. Isolation of degrading bacteria: After drying the tomato plants, cut them into small sections and put them into a liquid specialized carbon-deficient medium containing 4% (volume ratio) of bacterial source for restricted culture.

[0013] S2. Using the turbid bacterial culture from S1 as the inoculum, take a portion and inoculate it into a new liquid specialized carbon-deficient medium for further culture.

[0014] S3. After continuous restrictive subculturing for more than 5 generations, the resulting bacterial solution is the strain screened from the tomato plant.

[0015] Furthermore, the strain is selected from one or more of XNTD-1, XNTD-2, XNCD-4 and / or XNTD-13; the XNTD-1 has the accession number CGMCC NO. 34324 and the accession name XNTD-1, and the DNA sequence of the strain is shown in SEQ ID NO.1; the strain is classified and named as follows: Xenophilus sp. The XNTD-2 strain has the accession number CGMCC NO. 34325 and the accession name XNTD-2. Its DNA sequence is shown in SEQ ID NO. 2. The strain is classified as *Sphingosine monocytogenes*. Sphingobacterium sp. The XNCD-4 strain has the accession number CGMCC NO. 34328 and the accession name XNCD-4. Its DNA sequence is shown in SEQ ID NO. 3. The strain is classified as Microbacteria. Microbacterium sp. The XNTD-13 strain has the accession number CGMCC NO. 34326 and the accession name XNTD-13. Its DNA sequence is shown in SEQ ID NO. 4. The strain is classified as *Oligotrophomonas*. Stenotrophomonas sp. The strain was deposited on April 24, 2025; the deposit address of the strain is the China General Microbiological Culture Collection Center.

[0016] Thirdly, the present invention provides a method for culturing the strain described in the first aspect, the method comprising the following steps: S1. The strain was inoculated into R2A liquid medium and cultured to obtain fermentation broth; S2. Centrifuge the fermentation broth obtained in step S1, discard the supernatant, and the precipitate is the bacterial block of this strain; S3. Store the mycelium blocks in glycerol.

[0017] Furthermore, in step S1, the volume of the R2A liquid culture medium is selected from 15-45 mL, preferably 30 mL.

[0018] Furthermore, in step S1, the culture temperature is selected from 25-38℃, preferably 30℃.

[0019] Furthermore, in step S1, the culture is carried out in a shaker, the rotation speed of which is selected from 120-360 r / min, preferably 200 r / min.

[0020] Furthermore, in step S1, the culture time is selected from 2-5 days, preferably 3 days.

[0021] Furthermore, in step S2, the centrifugation temperature is selected from 0-10℃, preferably 4℃.

[0022] Furthermore, in step S2, centrifugation is carried out by a centrifuge, the centrifuge speed of which is selected from 2200-3600 rpm, preferably 3000 rpm.

[0023] Furthermore, in step S3, the concentration of the glycerol is selected from 25-38%; preferably 33%.

[0024] Further, the strain is selected from one or more of XNTD-1, XNTD-2, XNCD-4 and / or XNTD-13; XNTD-1 has accession number CGMCC NO. 34324, accession name XNTD-1, and its DNA sequence is shown in SEQ ID NO. 1; XNTD-2 has accession number CGMCC NO. 34325, accession name XNTD-2, and its DNA sequence is shown in SEQ ID NO. 2; XNCD-4 has accession number CGMCC NO. 34328, accession name XNCD-4, and its DNA sequence is shown in SEQ ID NO. 3; XNTD-13 has accession number CGMCC NO. 34326, accession name XNTD-13, and its DNA sequence is shown in SEQ ID NO. 4.

[0025] Fourthly, the present invention provides a microbial agent containing the strain described in the first aspect.

[0026] Further, the strain is selected from one or more of XNTD-1, XNTD-2, XNCD-4 and / or XNTD-13; XNTD-1 has accession number CGMCC NO. 34324, accession name XNTD-1, and its DNA sequence is shown in SEQ ID NO. 1; XNTD-2 has accession number CGMCC NO. 34325, accession name XNTD-2, and its DNA sequence is shown in SEQ ID NO. 2; XNCD-4 has accession number CGMCC NO. 34328, accession name XNCD-4, and its DNA sequence is shown in SEQ ID NO. 3; XNTD-13 has accession number CGMCC NO. 34326, accession name XNTD-13, and its DNA sequence is shown in SEQ ID NO. 4.

[0027] Furthermore, the bacterial agent is available in liquid and solid formulations.

[0028] Furthermore, the microbial agent includes nutrients and auxiliary components.

[0029] Furthermore, the nutrients include one or more of the following: carbon source, nitrogen source, phosphorus source, trace elements, and / or water.

[0030] Furthermore, the auxiliary ingredients include one or more of surfactants, surfactants, pH adjusters, humectants, stabilizers, penetrants, and / or antioxidants.

[0031] Fifthly, the present invention provides the application of the strain described in the first aspect of the present invention in the preparation of a microbial agent for degrading tomato straw, said strain being able to reduce the cellulose content of tomato straw.

[0032] Further, the strain is selected from one or more of XNTD-1, XNTD-2, XNCD-4 and / or XNTD-13; XNTD-1 has accession number CGMCC NO. 34324, accession name XNTD-1, and its DNA sequence is shown in SEQ ID NO. 1; XNTD-2 has accession number CGMCC NO. 34325, accession name XNTD-2, and its DNA sequence is shown in SEQ ID NO. 2; XNCD-4 has accession number CGMCC NO. 34328, accession name XNCD-4, and its DNA sequence is shown in SEQ ID NO. 3; XNTD-13 has accession number CGMCC NO. 34326, accession name XNTD-13, and its DNA sequence is shown in SEQ ID NO. 4.

[0033] Furthermore, the bacterial agent is available in liquid and solid formulations.

[0034] Furthermore, the microbial agent includes nutrients and auxiliary components.

[0035] Furthermore, the nutrients include one or more of the following: carbon source, nitrogen source, phosphorus source, trace elements, and / or water.

[0036] Furthermore, the auxiliary ingredients include one or more of surfactants, surfactants, pH adjusters, humectants, stabilizers, penetrants, and / or antioxidants.

[0037] Beneficial effects The four bacterial strains provided by this invention were all screened from tomato plants and possess the ability to degrade tomato straw waste, making them suitable for the reuse of agricultural waste. The fermentation broth of these strains can effectively degrade tomato straw waste. When the four strains treated straw individually, the average straw degradation rate reached 54.00%; the average hydrolysis value reached 2.30; and the average cellulose degradation rate reached 31.00%, all significantly higher than the water-treated control group. The weight loss rate of the tomato straw in the composite bacterial group was 56.03%, an increase of 41.53% compared to the control group. The strains of this invention are simple and low-cost to prepare, non-toxic, harmless, and environmentally friendly, facilitating the safe and effective degradation of tomato straw waste while also contributing to environmental protection. Attached Figure Description

[0038] Figure 1 The Neighbor-Joining phylogenetic tree for strains XNTD-1, XNTD-2, XNCD-4, and XNTD-13 was constructed based on the 16S rRNA gene sequence alignment results with Escherichia coli (LC848137.1) as the outer branch.

[0039] Figure 2 This image shows the effect of a single strain on straw degradation.

[0040] Note: CK is the water control group.

[0041] Figure 3 This image shows the effect of the compound microbial community in degrading straw.

[0042] Note: CK is the water control group; TC is the complex bacterial group. Detailed Implementation

[0043] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the embodiments described below can be combined with each other as long as they do not conflict with each other.

[0044] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0045] Example 1 Screening of tomato straw degrading bacteria A. Preprocessing The straw was cut into small pieces and placed in a liquid specialized carbon-deficient medium containing 4% (by volume) of inoculum. It was then cultured under restricted conditions at 30°C and 200 r / min.

[0046] Using the turbid bacterial culture from 10 days as the inoculum, 5 mL was inoculated into a new liquid carbon-deficient medium. All other materials and procedures remained unchanged, and the culture was continued with shaking. This restricted subculturing was repeated for at least 5 generations to obtain a specific, highly efficient, and synergistic degradative bacterial community capable of stably degrading tomato straw.

[0047] The bacterial culture was serially diluted 10-fold, and the serially diluted solutions were spread on LB medium for incubation. Different morphological bacteria were picked and streaked repeatedly to obtain single strains, which were then coded and stored in LB slant culture.

[0048] B. Initial screening Initial screening was performed using Congo red staining. The isolated single strains were inoculated onto screening medium and cultured. After staining with 1 mg / mL Congo red solution, the strains were destained with 1 mol / L NaCl solution. The diameter of the clear zone and the colony diameter were measured, and the hydrolysis value was calculated as: hydrolysis value = diameter of clear zone / colony diameter.

[0049] C. Secondary screening Strains with high hydrolysis values ​​were selected for secondary screening using the filter paper strip disintegration method. Filter paper strips and bacterial culture were added to Hutchison Inorganic Salt Medium and cultured, with an equal volume of sterile water added as a blank control. The disintegration of the filter paper was observed. Simultaneously, the aniline blue decolorization method was used to detect whether the screened strains possessed lignin degradation ability.

[0050] Example 2 Molecular biological identification of four tomato straw-degrading strains 16S rDNA gene sequencing and phylogenetic tree construction. Bacterial DNA was extracted using a DNA extraction kit, and specific PCR amplification was performed using the universal bacterial primer 27F (TACGGYTACCTTGTTACGACTT)-1492R (AGAGTTTGATCMTGGCTCAG). The PCR products were sequenced, and the 16S rDNA nucleotide sequence lengths of each strain were determined to be 1275 bp, 1355 bp, 1389 bp, and 1277 bp, respectively. Similarity analysis was performed between these sequences and relevant data in GenBank. Phylogenetic trees were constructed by comparing the 16S rDNA sequences with those of strains in NCBI.

[0051] Based on the comprehensive analysis of the strains' culture characteristics, morphological and physiological-biochemical features, and 16S rDNA sequence, XNTD-1, XNTD-2, XNCD-4, and XNTD-13 were ultimately identified as... Betaproteobacteria Xenophilus, Proteobacteria Sphingobacterium, Microbacterium, Gammaproteobacteria Stenotrophomonas .

[0052] Example 3: Validation of the Tomato Straw Degradation Function of a Single Straw Strain A. Test methods 1. Hydrolysis value The isolated single strains were inoculated onto screening medium and cultured. After incubation, they were stained with 1 mg / mL Congo red solution and destained with 1 mol / L NaCl solution. The diameter of the transparent zone and the diameter of the colony were measured, and the hydrolysis value was calculated as follows: hydrolysis value = diameter of transparent zone / diameter of colony.

[0053] 2. Straw weight loss rate Single-source bacterial suspensions of XNTD-1, XNTD-2, XNCD-4, and XNTD-13 were cultured separately. 5 g of straw was cut into small pieces and placed in 125 mL of liquid carbon-deficient medium containing 4% (v / v) of a single bacterial source. Restrictive culture was performed at 30℃ and 200 r / min. After 10 days, the straw was removed from the medium, blanched, and dried to constant weight. The straw weight loss rate was calculated by measuring the weight after drying: Straw weight loss rate = (Straw weight before treatment - Straw weight after degradation) / Straw weight before treatment × 100%.

[0054] The straw in question is tomato straw.

[0055] 3. Cellulose degradation Add filter paper strips and bacterial culture to Hutchison Inorganic Salt Medium and culture. Add an equal amount of sterile water as a blank control. Observe the disintegration of filter paper and calculate the cellulose degradation rate. Cellulose degradation rate = (mass of filter paper - mass after degradation) × 100%.

[0056] B. Test results 1. Hydrolysis value Hydrolysis zone experiments showed that the hydrolysis value of strain XNTD-1 was 3.25; that of strain XNTD-2 was 2.06; that of strain XNCD-4 was 2.25; and that of strain XNTD-13 was 1.62; with an overall average of 2.30. This indicates that each individual strain possesses a strong ability to secrete cellulase, suggesting that these strains have potential application value as cellulose-degrading bacteria.

[0057] 2. Straw weight loss rate Through straw degradation experiments, phenotypic observation revealed that the tomato straw treated with various degrading strains had many pores on its surface and was loose like cotton, indicating that the degrading bacteria rapidly and deeply decomposed the tomato straw. In contrast, the straw treated with CK (water) softened but retained its shape, indicating a poor degradation effect.

[0058] As shown in Table 1, after water treatment, the straw weight loss rate of the CK group was 40.14%; the straw weight loss rate of strain XNTD-1 was 54.79%; the straw weight loss rate of strain XNTD-2 was 53.12%; the straw weight loss rate of strain XNCD-4 was 58.25%; and the straw weight loss rate of strain XNTD-13 was 49.83%; the overall average reached 54.00%. The straw weight loss rate under each strain treatment increased by 36.50%, 32.34%, 45.12%, and 24.14% respectively compared with the CK treatment, indicating that each degrading strain had a significant promoting effect on straw degradation, with XNCD-4 showing the most significant effect.

[0059] Table 1. Validation of the tomato straw degradation function of a single strain Note: Different lowercase letters in the table indicate different meanings. P The difference was significant at the <0.05 level.

[0060] 3. Cellulose degradation Cellulose degradation characteristic tests showed that different strains had different abilities to degrade cellulose.

[0061] The cellulose degradation rate of strain XNTD-1 was 40.75%; that of strain XNTD-2 was 30.75%; that of strain XNCD-4 was 31.50%; and that of strain XNTD-13 was 21.00%; the overall average was 31.00%. This shows that each individual strain had a high cellulose degradation rate, with strain XNTD-1 exhibiting the strongest degradation ability.

[0062] Example 4: Verification of the degradation function of tomato straw by a compound microbial community A. Test methods 1. Straw weight loss rate Five g of straw was cut into small pieces and placed in 125 mL of a specialized carbon-deficient liquid culture medium containing 4% (v / v) XNTD-1, XNTD-2, XNCD-4, and XNTD-13 mixed inoculum in a 1:1:1:1 v / v ratio. The medium was then used for restrictive culture at 30℃ and 200 r / min. After 10 days, the straw was removed from the culture medium, blanched, and dried in an oven to constant weight. The weight loss rate of the straw was calculated by measuring its weight after drying: Straw weight loss rate = (straw weight before treatment - straw weight after degradation) / straw weight before treatment × 100%.

[0063] B. Test results The straw degradation test showed that when XNTD-1, XNTD-2, XNCD-4 and XNTD-13 were mixed in a volume ratio of 1:1:1:1, the weight loss rate of the tomato straw under the compound microbial community was 56.03%, which was 41.53% higher than that of the CK treatment. This indicates that the compound microbial community can increase the decomposition rate of straw.

Claims

1. Application of a group of bacterial strains in the preparation of an inoculant for degrading tomato straw, wherein the strains reduce the cellulose content of tomato straw; the strains were obtained from tomato plants through screening, and the strains are xenotrophic bacteria XNTD-1, *Sphingobacterium* XNTD-2, *Microbacterium* XNCD-4, and *Oligotrophomonas* XNTD-13; XNTD-1 has the accession number CGMCC NO. 34324, accession name XNTD-1, and its DNA sequence is shown in SEQ ID NO. 1; the strain is classified as *Xenophilus* sp.; XNTD-2 has the accession number CGMCC NO. 34325, accession name XNTD-2, and its DNA sequence is shown in SEQ ID NO. 2; the strain is classified as *Sphingobacterium* sp.; XNCD-4 has the accession number CGMCC NO. 34328, accession name XNCD-4, and its DNA sequence is shown in SEQ ID NO.

1. As shown in NO.3; the strain is classified and named Microbacterium sp.; the XNTD-13 accession number is CGMCC NO. 34326, accession name XNTD-13, and the DNA sequence of the strain is shown in SEQ ID NO.4; the strain is classified and named Stenotrophomonas sp.; the accession date of the strain is April 24, 2025; the accession address of the strain is China General Microbiological Culture Collection Center.

2. A group of bacterial strains screened from tomato plants that degrade tomato straw, comprising xenoophilic bacteria XNTD-1, *Sphingobacterium* XNTD-2, *Microbacterium* XNCD-4, and *Oligotrophomonas* XNTD-13; XNTD-1 has the accession number CGMCC NO.34324 and the accession name XNTD-1, and its DNA sequence is shown in SEQ ID NO.1; the strain is classified as *Xenophilus* sp.; XNTD-2 has the accession number CGMCC NO. 34325 and the accession name XNTD-2, and its DNA sequence is shown in SEQ ID NO.2; the strain is classified as *Sphingobacterium* sp.; XNCD-4 has the accession number CGMCC NO. 34328 and the accession name XNCD-4, and its DNA sequence is shown in SEQ ID NO.3; the strain is classified as *Microbacterium*. sp.; The XNTD-13 accession number is CGMCC NO. 34326, the accession name is XNTD-13, and the DNA sequence of the strain is shown in SEQ ID NO.4; The strain is classified and named Stenotrophomonas sp.; The accession date of the strain is April 24, 2025; The accession address of the strain is China General Microbiological Culture Collection Center.

3. A method for screening strains from tomatoes, said strain as described in claim 1, the method comprising the following steps: S1. Isolation of degrading bacteria: After drying the tomato plants, cut them into small sections and put them into a liquid specialized carbon-deficient medium containing 4% (v / v) inoculum for restricted culture; S2. Using the turbid bacterial culture from S1 as the inoculum, take a portion and inoculate it into a new liquid carbon-deficient medium, and continue culturing. S3. After continuous restrictive subculturing for more than 5 generations, the resulting bacterial solution is the strain screened from the tomato plant.

4. The method of claim 3, wherein the strain is selected from one or more of XNTD-1, XNTD-2, XNCD-4 and / or XNTD-13; XNTD-1 has accession number CGMCC NO. 34324, accession name XNTD-1, and its DNA sequence is shown in SEQ ID NO. 1; the strain is classified as Xenophilus sp.; XNTD-2 has accession number CGMCC NO. 34325, accession name XNTD-2, and its DNA sequence is shown in SEQ ID NO. 2; the strain is classified as Sphingobacterium sp.; XNCD-4 has accession number CGMCC NO. 34328, accession name XNCD-4, and its DNA sequence is shown in SEQ ID NO. 3; the strain is classified as Microbacterium sp.; and XNTD-13 has accession number CGMCC NO. 34326, deposited under the name XNTD-13, has the DNA sequence shown in SEQ ID NO.4; the strain is classified as Stenotrophomonas sp.; the deposit date is April 24, 2025; and the deposit address is the China General Microbiological Culture Collection Center.

5. A method for culturing a strain screened from tomato plants, the method comprising the following steps: S1. The strains screened from tomato plants were inoculated into R2A liquid medium and cultured at 30℃ and 200 r / min to obtain fermentation broth; S2. Centrifuge 4000g of the fermentation broth obtained in step S1 for 10 minutes, discard the supernatant, and the precipitate is the bacterial block of this strain; S3. Store the mycelium blocks in glycerol.

6. The method of claim 5, wherein the strain is selected from one or more of XNTD-1, XNTD-2, XNCD-4 and / or XNTD-13; XNTD-1 has accession number CGMCC NO. 34324, accession name XNTD-1, and its DNA sequence is shown in SEQ ID NO. 1; the strain is classified as Xenophilus sp.; XNTD-2 has accession number CGMCC NO. 34325, accession name XNTD-2, and its DNA sequence is shown in SEQ ID NO. 2; the strain is classified as Sphingobacterium sp.; XNCD-4 has accession number CGMCC NO. 34328, accession name XNCD-4, and its DNA sequence is shown in SEQ ID NO. 3; the strain is classified as Microbacterium sp.; and XNTD-13 has accession number CGMCC NO. 34326, deposited under the name XNTD-13, has the DNA sequence shown in SEQ ID NO.4; the strain is classified as Stenotrophomonas sp.; the deposit date is April 24, 2025; and the deposit address is the China General Microbiological Culture Collection Center.

7. A microbial agent containing the strain as described in claim 2.

8. The bacterial agent according to claim 7, wherein the bacterial strain is selected from one or more of XNTD-1, XNTD-2, XNCD-4 and / or XNTD-13; the XNTD-1 has accession number CGMCC NO. 34324, accession name XNTD-1, and the DNA sequence of the strain is shown in SEQ ID NO. 1; the strain is classified as Xenophilus sp.; the XNTD-2 has accession number CGMCC NO. 34325, accession name XNTD-2, and the DNA sequence of the strain is shown in SEQ ID NO. 2; the strain is classified as Sphingobacterium sp.; the XNCD-4 has accession number CGMCC NO. 34328, accession name XNCD-4, and the DNA sequence of the strain is shown in SEQ ID NO. 3; the strain is classified as Microbacterium sp.; and the XNTD-13 has accession number CGMCC NO. 34326, deposited under the name XNTD-13, has the DNA sequence shown in SEQ ID NO.4; the strain is classified as Stenotrophomonas sp.; the deposit date is April 24, 2025; and the deposit address is the China General Microbiological Culture Collection Center.

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