A Strain of Sphingobacillus crustosus and Its Application

Abstract

The present invention belongs to the field of microorganisms, and specifically discloses a strain of Sphingobacterium shellycum and its application. The Sphingobacterium shellycum (Sphingobacteriumputeale) strain TYQ6 was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on April 27, 2023, with a deposit number of CGMCC.27215. The applicant found through experiments that the above-mentioned Sphingobacterium shellycum can secrete auxin, which can promote the growth of cucumber seedlings. It also has the ability to enhance the cucumber seedlings' ability to resist drought, interfere with the tropism migration of nematodes, and kill nematodes; therefore, the above-mentioned Sphingobacterium shellycum has broad application prospects in agricultural production.

Description

Technical Field

[0001] The invention belongs to the field of microorganisms and specifically discloses a shell-shaped sphingobacterium and application thereof. Background Art

[0002] Beneficial rhizosphere microorganisms refer to those microorganisms that live freely in the soil or attach to plant roots. They can promote plant growth, improve the absorption and utilization of mineral nutrients by plants, and inhibit the growth of harmful organisms. At present, a large number of beneficial rhizosphere microbial strains have been screened and identified. The application of these resources in agricultural production can significantly improve plant growth and development, prevent diseases and pests, and reduce the application of chemical fertilizers, which is of great significance for achieving sustainable agricultural development.

[0003] Southern root-knot nematodes are one of the most important diseases in agricultural production. They parasitize on plant roots, causing root knots and root deformities, which seriously affect the plant's nutrient absorption and growth and development, leading to a decrease in crop yields. Although chemical control methods are effective, long-term use can lead to environmental pollution and increased nematode resistance. Therefore, biological control methods have gradually gained attention. Beneficial rhizosphere microorganisms with nematode-inhibiting effects can serve as a safe and environmentally friendly alternative and play an important role in the prevention and control of nematode diseases.

[0004] Drought is one of the important limiting factors affecting agricultural production. Drought stress can destroy the integrity of plant cell membranes, hinder the transport of water and nutrients, reduce photosynthesis efficiency, and ultimately affect plant growth and yield. Using beneficial rhizosphere microorganisms to enhance the drought resistance of plants is an effective biological regulation method. These microorganisms can improve soil structure, increase soil water retention capacity, promote plant root growth, and enhance the adaptability of plants to drought environments, thereby alleviating the negative impact of drought on plants.

[0005] In agricultural production, rhizosphere beneficial microorganisms with comprehensive functions are of great significance. They can not only promote plant growth and increase yield, but also enhance plant resistance to stress and prevent and treat diseases and insect pests. For example, some microorganisms can directly promote plant growth by synthesizing plant hormones such as auxin, or increase the plant's absorption of mineral nutrients by changing the form of effective elements in the soil. In addition, these microorganisms can also secrete antibiotics to inhibit the growth of harmful microorganisms and protect plants from diseases.

[0006] In short, the development and application of rhizosphere beneficial microorganisms with diverse functions is of great significance for promoting high-quality and efficient production in modern agriculture. By rationally utilizing these microbial resources, we can not only reduce the use of chemical pesticides and fertilizers and protect the environment, but also improve the yield and quality of crops and achieve sustainable agricultural development. Summary of the invention

[0007] Based on the deficiencies in the prior art, the invention discloses a shell-like sphingobacterium and application thereof.

[0008] The present invention includes the following technical solutions:

[0009] A Sphingobacterium puteale strain TYQ6 is deposited in the General Microbiology Center of China Microbiological Culture Collection Administration with a deposit number of CGMCCNO.27215. The strain is isolated from cucumber rhizosphere soil in the laboratory of China Agricultural University.

[0010] Further, the single colony of the above-mentioned Sphingobacterium puteale is round, light yellow and opaque, with a colony size of 1-3mm, a smooth and shiny surface, regular edges, a rod-shaped body, Gram staining is negative, and the optimal growth temperature is 25-30°C. The ability of TYQ6 to utilize or oxidize different pre-selected carbon sources was detected using Biolog GenIII microplates, thereby forming a metabolic fingerprint of TYQ6 utilizing different carbon sources. It was found that TYQ6 can utilize 38 carbon sources to varying degrees and is insensitive to 3 chemical reagents. By amplifying the 16S rDNA fragment of the strain and performing BLAST homology comparison, the strain has a similarity of 98.63% to Sphingobacterium puteale. Therefore, the strain was identified as a strain of the genus Sphingobacterium puteale and named Sphingobacterium puteale TYQ6.

[0011] The invention also discloses a microbial agent, which contains the above-mentioned Sphingobacillus crustosa cells and / or its metabolites and / or its fermentation liquid.

[0012] Furthermore, the present invention discloses the use of the above-mentioned bacteria or bacterial agent in the preparation of a preparation for promoting the growth of cucumber seedlings. In some embodiments, when the cotyledons of the cucumber seedlings are flattened, the TYQ6 fermentation liquid is poured into the root soil, and 10 ml is poured for each seedling. This application increases the height and stem thickness of the seedlings, promotes biomass accumulation, and is conducive to the cultivation of strong seedlings.

[0013] Furthermore, the present invention discloses the use of the above-mentioned bacteria or bacterial agent in the preparation of a preparation for enhancing the ability of cucumber seedlings to resist drought. In some embodiments, when the cucumber seedlings have three leaves and one heart, the TYQ6 fermentation liquid is irrigated in the root soil treated with drought or infected with root-knot nematodes, and 10 ml is irrigated for each seedling. This application improves the drought resistance of cucumber seedlings and effectively reduces the damage of drought stress to plant cell membranes.

[0014] Furthermore, the present invention discloses the use of the above-mentioned bacteria or bacterial agents in the preparation of preparations for interfering with the migration of southern root-knot nematodes. In some embodiments, when the cotyledons of cucumber seedlings are flattened, TYQ6 fermentation liquid is poured into the root soil, and 10 ml is poured into each seedling. This application causes the migration of southern root-knot nematodes to the control root system by 60.09%.

[0015] Furthermore, the present invention discloses the use of the above-mentioned bacteria or bacterial agent in the preparation of a preparation for controlling southern root-knot nematodes. In some embodiments, the TYQ6 metabolite solution was co-cultured with the second-instar larvae of southern root-knot nematodes, and the calibrated mortality rate was 89.2%.

[0016] Compared with the prior art, the present invention has the following outstanding beneficial effects:

[0017] The invention discloses a shell-shaped sphingobacillus and its application. The shell-shaped sphingobacillus TYQ6 has good anti-stress growth-promoting effect and has broad application prospects in agricultural production. In terms of growth promotion, the strain can significantly promote the growth of cucumber seedlings. When inoculated with TYQ6, the plant height and stem thickness of the cucumber plant are significantly promoted, and the growth is increased by 6.00% and 92.31% respectively. In addition, the accumulation of cucumber substances is also promoted, and the fresh weight of the aboveground part and the fresh weight of the underground part are significantly increased by 27.42% and 30.25%. Under drought stress, TYQ6 inoculation can help cucumber seedlings reduce water loss, maintain the stability of the water content of the plant, and significantly improve the structural stability of mesophyll cells, alleviating the damage of drought stress to plant cell membranes. Under the stress of root-knot nematodes, inoculation with TYQ6 significantly reduces the number of root knots per unit weight of cucumber seedlings by 30.15% compared with the control, indicating that TYQ6 can effectively assist cucumbers in resisting the infection of root-knot nematodes and is beneficial to the early prevention and control of root-knot nematodes.

[0018] The strain deposit information is as follows:

[0019] Name of depository: General Microbiology Center of China Microbiological Culture Collection Administration;

[0020] Address of the depository: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing;

[0021] Deposit date: April 27, 2023;

[0022] Deposit number: CGMCC NO.27215;

[0023] Taxonomic name: Sphingobacterium puteale. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the morphological characteristic diagram of a single colony obtained by streaking separation of TYQ6;

[0025] Figure 2 This is the fingerprint of TYQ6's ability to utilize different carbon sources;

[0026] Figure 3 This is the phylogenetic tree diagram of TYQ6;

[0027] Figure 4 This is a diagram showing the effect of TYQ6 inoculation on the tropism and migration of southern root-knot nematodes;

[0028] Figure 5 This is a diagram showing the effect of TYQ6 inoculation on the tropism and migration of southern root-knot nematodes;

[0029] Figure 6 This is a graph showing the effect of TYQ6 fermentation supernatant on the in vitro contact killing of southern root-knot nematodes;

[0030] Figure 7 This is a graph showing the in vitro contact killing effect of TYQ6 fermentation supernatant on southern root-knot nematodes;

[0031] Figure 8 This is a diagram showing the effect of TYQ6 inoculation on cucumber roots infected by southern root-knot nematodes;

[0032] Fig. 9 This is a picture showing the effect of TYQ6 inoculation on root knots in cucumber roots infected by southern root-knot nematodes;

[0033] Fig.10 This is the effect of TYQ6 inoculation on the root knots of cucumber root system infected by southern root-knot nematodes;

[0034] Fig.11 This is the effect of TYQ6 on the growth indexes of cucumber seedlings;

[0035] Fig.12 This is a picture showing the effect of TYQ6 in helping cucumber seedlings tolerate drought;

[0036] Fig.13 A diagram showing the effect of TYQ6 on drought tolerance in cucumber seedlings. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] Isolation, purification and identification of Sphingobacterium puteale TYQ6.

[0040] 1.1 Isolation and purification of Sphingobacterium puteale strain TYQ6:

[0041] The Sphingobacterium puteale strain TYQ6 of the present invention was isolated from the rhizosphere soil of cucumbers infested with root-knot nematodes in the laboratory of China Agricultural University. The isolation method was a soil dilution method. The specific steps are as follows:

[0042] The separation method uses the soil dilution method, and the steps are as follows: First, collect 4 soil samples, all of which are from the rhizosphere of cucumber plants with root-knot nematodes in the vegetable growth and development regulation laboratory of China Agricultural University. Each sample is 1g, and they are mixed evenly. The mixed soil is quickly placed in a 50ml centrifuge tube containing 9ml sterile distilled water, and put into a shaker (speed of 180rpm / min) and shaken for 20 minutes before taking out. Next, take ml soil suspension into a new centrifuge tube, add 9ml sterile water, dilute it 10 times, and so on for a series of gradient dilutions. Finally, draw 100μL of the soil suspension with the corresponding dilution multiple onto the LB solid culture medium plate and culture it at 28℃ in a light incubator for 2 days. After a single colony grows on the plate, perform three consecutive streaking separation and purification.

[0043] 1.2 Identification of Sphingobacterium puteale strain TYQ6

[0044] (1) Microbiological characteristics

[0045] The obtained strain was inoculated on LB medium plates and cultured at 28°C for 2 days. Figure 1 As shown, the single colony of the strain is round, light yellow and opaque, with a colony size of 1-3 mm, a smooth and shiny surface, regular edges, and a rod-shaped body. Gram staining is negative. At the same time, the utilization or oxidation ability of the TYQ6 strain on various pre-selected carbon sources was detected by using the Biolog GenIII microplate. The test generates the metabolic fingerprint of TYQ6 for different carbon sources by measuring the absorbance value of the reaction solution at OD590 nm. The results are shown in Figure 2 As shown, the higher the OD value, the higher the utilization rate of the carbon source. Among the 71 carbon sources, it was found that TYQ6 was able to utilize 38 of them to varying degrees. In addition, in the test of 21 chemical reagents, TYQ6 showed insensitivity to 3 of them.

[0046] (2) Molecular biological characteristics

[0047] A single colony was picked and placed in a 1.5 mL centrifuge tube containing 1 mL of LB medium, and cultured at 28°C and 180 rpm / min for 24 h. The bacterial culture was used as a template to amplify the 16S rRNA sequence using primers 27F and 1492R.

[0048] The PCR amplification reaction system was 50 μL, including 25 μL 2xTaq enzyme, 1 μL 27F primer, 1 μL 1492R primer, 1 μL bacterial solution and 22 μL ddH 2 O. Amplification conditions were: 95°C pre-denaturation for 3 min, 94°C denaturation for 25 s, 55°C annealing for 25 s, 72°C extension for 1 min, 32 cycles, 72°C extension for 5 min, and the amplified product was stored at 4°C. The amplified product was separated and identified by 1% agarose gel electrophoresis, and the PCR product was sent to Beijing Qingke Biotechnology Co., Ltd. for bidirectional sequencing. The 16S rDNA of strain TYQ6 is shown in the following SEQ ID NO: 1:

[0049] TTGCGGTCACATGCTTTAGGTACCCCCAACTTTCATGGCTTGACGGGCGGTGTGTACAAGGCCCGGGAACGTATTCACCGCGTCATTGCTGATACGCGATTACTAGCGAATCCAACTTCATGGGGTCGAGTTGCAGACCCCAATCCGAACTGTGAATGGCTTTTAGAGATTAGCACCATATTGCTATGTAGCTGCCCGCTGTACCATCCATTGTAGCACGTGTGTAGCCCCGGACGTAAGGGCCATGATGACTTGACGTCGTCCCCACCTTCCTCTCTGCTTGCGCAGGCAGTCTGTTTAGAGTCCCCACCACTACATGCTGGCAACTAAACATAGGGGTTGCGCTCGTTGCGGGACTTAACCCAACACCTCACGGCACGAGCTGACGACAGCCATGCAGCACCTAGTTTCGTGTCCCGAAGGACGGATGCGTCTCTGCATCCTTCACTAACTTTCAAGCCCGGGTAAGGTTCCTCGCGTATCATCGAATTAAACCACATGCTCCTCCGCTTGTGCGGGCCCCCGTCAATTCCTTTGAGTTTCACCCTTGCGGGCGTACTCCCCAGGTGGATAACTTAACGCTTTCGCTTGGACGCTGGCGGTCTATCGCCAACATCGAGTTATCATCGTTTAGGGCGTGGACTACCAGGGTATCTAATCCTGTTCGATCCCCACGCTTTCGTGCATCAGCGTCAATACCAGCTTAGTGAGCTGCCTTCGCAATCGGAGTTCTAAGACATATCTATGCATTTCACCGCTACTTGTCTTATTCCGCCCACTTCAAATGGATTCAAGCCCGTCAGTATCAAAGGCACTGCGATGGTTGAGCCACCGTATTTCACCCCTGACTTAACAGGCCGCCTACGCACCCTTTAAACCCAATAAATCCGGATAACGCTCGGATCCTCCGTATT ACCCGGCTGCTGGCACGGAGTTAGCCGATCCTTATTCTTCCAGTACATTCAGCCAGATACTCGTATCTGGGTTTTATTCCTGGACAAAAGCAGTTTACAACCCATAGGGCAGTCATCCTGCACGCGGCATGGCTGGTTCAGGCTTCCGCCCATTGACCA ATATTCCTTACTGCTGCCTCCCGTAGGAGTCTGGTCCGTGTCTCCAGTACCAGTGTGGGGGATTCTCCTCTCAGAGCCCCTAGACATCGTCGCCTTGGTAGGCCGTTACCCTACCAACTAGCTAATGTCACGCGAGCCCATCTCTATCCTATAAATATTT AATCAACCGAACATGCGAACTGTTGATGTTATGCGGTGTTAATCTCTCTTTCGAGAGGCTATCCCCCTGATAGAGGTAGGTTGCTCACGCGTTACGCACCCGTGCGCCACTCTCATTAACTTAAAGCAAGCTTTGGTGTTAAATCCCGTCCGACTTGCA

[0050] The results of the assay were compared using BLAST homology, and the results showed that the strain had a similarity of 98.63% with Sphingobacterium puteale strain M05W1-28. Figure 3 The strain was identified as a strain of the genus Sphingobacteriaceae, named Sphingobacterium puteale strain TYQ6, and deposited in the General Microbiological Center of China Microbiological Culture Collection Administration with a deposit number of CGMCC NO.27215.

[0051] Example 2

[0052] Effect of fermentation supernatant of Sphingobacillus crustosus TYQ6 on the tropism and migration of root-knot nematodes.

[0053] 2.1 Preparation of strain suspension

[0054] The test strain is Sphingobacterium TYQ6, and the control strain is Microbacterium paraoxydans strain, which is an existing strain in the laboratory. Pick a single colony of the TYQ6 strain and inoculate it in a conical flask containing 30mL LB liquid culture medium, and shake and culture it overnight at 28°C and 180rpm / min. Dilute the enriched bacterial solution to OD600=0.8, then centrifuge it at 10000rpm / min for 10 minutes, remove the supernatant and save the bottom bacteria. Use 10mM / L MgSO4 to resuspend the strain and prepare the bacterial solution for use.

[0055] 2.2 Cucumber root preparation

[0056] Cucumber is a vegetable crop that is sensitive to southern root-knot nematodes. In this example, cucumber is used as a model crop for research.

[0057] Select plump and intact cucumber seeds for surface disinfection, soak them in 75% ethanol for 30 seconds, rinse them with sterile distilled water three times, soak them in 3% NaClO solution for 10 minutes, rinse them with sterile distilled water three times until there is no reagent residue, soak them in sterile water for 6 hours, transfer the seeds to a culture dish with moistened sterile filter paper, and place them in a 28℃ incubator for germination. When the cotyledons are flattened (about 5-7 days), inoculate 10 ml of the prepared bacterial solution in advance, and take the roots for testing when two leaves and one heart are inoculated.

[0058] 2.3 Preparation of second-instar larvae suspension of root-knot nematodes

[0059] The southern root-knot nematode used in the present invention is isolated from the infected water spinach root system. First, the water spinach root system is cleaned, and the egg mass on the root surface is picked up with tweezers. Subsequently, the egg mass is shaken and cleaned with a 0.6% sodium hypochlorite solution and filtered through a 600-mesh sieve. The egg mass on the sieve is repeatedly rinsed with sterile water, and finally transferred to a round culture dish filled with sterile water, and a 0.004 mg / mL gentamicin solution is added to prevent the growth of miscellaneous bacteria. After incubation at room temperature for 2 to 3 days, the hatched second-instar larvae are collected, observed and counted under a microscope, and the larval density is finally adjusted to 100 per 100 μL.

[0060] 2.4 23% Pluronic F-127 Gel Configuration

[0061] 23% Pluronic F-127 gel preparation: Prepare the solution at 4°C. Add 23g of F-127 gel powder to 80ml of 4°C pre-cooled sterile water and place on a magnetic stirrer to stir at a low speed. The dissolved gel is stored at 4°C.

[0062] 2.5 Migration assay

[0063] like Figure 5 In this experiment, a control group CK without bacterial solution and a bacterial solution group were set up, and each treatment was repeated 20 times. For the two-way selection gel migration experiment, a space was reserved in the nematode inoculation area with an Oxford cup with a diameter of 0.5 cm to provide a gap for the subsequent inoculation of nematodes. The roots of the control group and the experimental group were placed on both sides of the migration plate, and agar gel was added to the migration plate. It was placed at room temperature. After the gel solidified, the Oxford cup was taken out, and 100 μl of nematodes were added to the central gap. After being shielded from light and left to stand for 12 hours, the migration of nematodes was observed. The migration of nematodes on both sides was observed under a microscope, and the number of nematodes in different areas of the square culture dish was calculated. The movement trend of nematodes was calculated based on the total number of nematodes in the culture dish.

[0064] 2.6 Results Analysis

[0065] like Figure 6 The tropism migration test shows that the tyq6 single bacterium has the most significant effect on the nematode tropism. The percentage of nematode migration to the root tip of cucumber in the CK group reached 60.07%, which was significantly higher than the side of the cucumber root system with tyq6. It has a significant effect on the tropism of nematodes. Although the control strains 1 and 2 also have a tropism effect on nematodes, their migration effect is not as significant as that of tyq6.

[0066] Example 3

[0067] Effect of fermentation supernatant of Sphingobacillus crustosus TYQ6 on the tropism and migration of root-knot nematodes.

[0068] 3.1 Preparation of supernatant from fermentation broth

[0069] The test strain was Sphingobacillus TYQ6, and the control strain and bacterial suspension were the same as those used in Example 2. After the bacterial suspension was prepared, it was centrifuged at 10000 rpm / min for 5 minutes, and then the supernatant in the centrifuge tube was aspirated with a syringe and filtered with a 0.22 μm filter membrane. The solution obtained after filtration was the fermentation supernatant of Sphingobacillus TYQ6.

[0070] 3.2 In vitro contact test

[0071] 400 μL of the fermentation supernatant of the TYQ6 strain and the control strain was taken into a 48-well cell culture plate, and 100 μL of the second-instar larvae suspension of the root-knot nematode (containing 100 second-instar larvae) was added. 400 μL of sterile water was added to the control group. The cell culture plate was wrapped with tin foil and placed in a 28°C incubator. The survival status of the second-instar larvae was observed under a stereo microscope 12 h and 24 h after treatment. The judgment criteria were: after adding 1 mol / L NaOH solution to each treatment, those that remained stiff and motionless were dead worms, and those that bent and wriggled were alive worms. The number of dead nematodes was counted, and the corrected mortality rate of nematodes was calculated.

[0072]

[0073] 3.3 Results Analysis

[0074] like Figure 6 and Figure 7 As shown in the figure, after the TYQ6 fermentation supernatant was used to treat the nematodes, it was obviously lethal to the root-knot nematodes, and its corrected mortality rate for the second-instar larvae of the root-knot nematodes was higher than that of the control strain. Through delayed observation, it can be found that TYQ6 has the most effective lethality compared with the control strain, from 73.85% at the beginning of 12 hours to 83.06% at 24 hours. The above results show that the metabolites contained in the fermentation supernatant of the strain TYQ6 are highly lethal to the second-instar larvae of the southern root-knot nematode.

[0075] Example 4

[0076] Pot experiment on the control of southern root-knot nematode by Sphingobacillus crustosus TYQ6.

[0077] Cucumber is the most sensitive vegetable crop to southern root-knot nematodes. This example uses cucumber as a model crop for research.

[0078] The treatments in this embodiment are as follows: ① inoculation of root-knot nematodes (CK+N); ② inoculation of TYQ6 bacterial agent (TYQ6); ④ inoculation of both TYQ6 bacterial agent and root-knot nematodes (TYQ6+N). The specific implementation steps are as follows:

[0079] 4.1 Seed disinfection

[0080] The specific operation of seed disinfection is the same as that in Example 2.

[0081] 4.2 Strain inoculation

[0082] When the radicle grows out, sow the seeds in a 50-hole tray filled with sterilized soil. When the seedlings grow to the point where the first true leaf just emerges, start watering with TYQ6 inoculant, 10 mL per seedling, once a week and for three consecutive times.

[0083] The preparation method of sterilized soil is as follows: forest soil is collected and sieved, and then sterilized at 120°C for 1 hour, and sterilized again at high temperature after 24 hours. The preparation method of TYQ6 inoculant is as follows: TYQ6 is inoculated into LB liquid culture medium, and the bacterial solution is cultured to OD600 of 0.8 at 180 rpm / min and 28°C, and then the bacterial solution is centrifuged at 8000 rpm / min for 5 minutes, the supernatant is discarded, and an equal volume of 10 mM MgSO is used. 4 The bacterial agent is obtained after suspension in buffer.

[0084] 4.3 Inoculation of second-instar larvae of southern root-knot nematode

[0085] When the cucumber seedlings are in the one-leaf-one-heart stage, they are inoculated with the second-instar larvae of southern root-knot nematodes. Use a gun tip to poke two small holes about 1 cm deep around the root of the cucumber seedlings, add the root-knot nematode suspension into them, and inoculate 250 root-knot nematodes per seedling. On the 21st day after the nematode inoculation, samples are taken to count the root physiological indicators and root knot number of the cucumber plants.

[0086] 4.4 Results Analysis

[0087] The results showed that the cucumber seedlings treated with Sphingobacterium TYQ6 and infected with root-knot nematodes for 21 days Figure 8 The invention discloses the effects of the Sphingobacillus capsulosus TYQ6 on the total root length, root surface area, average root diameter and root volume of the healthy cucumber seedlings and the root system of the diseased plants. Fig. 9 This is a diagram of the cucumber root system 21 days after the nematode inoculation of Sphingobacterium TYQ6 of the present invention.

[0088] The roots of cucumber seedlings were scanned using a root scanner and analyzed using WinRHIZO analysis system software. The results are as follows: Figure 8 and Fig. 9 As shown. Figure 8 It can be seen that inoculation with Sphingobacterium crustosum TYQ6 significantly promoted the root growth of cucumber seedlings. In the presence of root-knot nematode infection, the total root length, root surface area, average root diameter and root volume of cucumber seedlings inoculated with TYQ6 strain increased by 4.05%, 8.25%, 6.46% and 18.44% respectively compared with the control.

[0089] Fig. 9 and Fig.10 The results showed that 21 days after inoculation with nematodes, inoculation with TYQ6 significantly reduced the number of root knots per unit root weight of cucumber roots, with the number of root knots per unit root weight of cucumber roots reduced by 30%, and its control effect on root-knot nematodes was significantly higher than that of the control strain.

[0090] The above results show that the TYQ6 strain of Sphingobacillus crustosus not only slows down the development process of root-knot nematodes in the cucumber root system and significantly reduces the number of root knots per unit in the cucumber root system, but also promotes root development and growth, which is beneficial to the early prevention and control of root-knot nematodes and helps to achieve safe and pollution-free production of vegetables.

[0091] Example 5

[0092] TYQ6 has a growth-promoting effect on plants.

[0093] Using cucumber as the test material, a pot experiment was conducted to determine the ability of TYQ6 to promote plant growth. The specific implementation steps are as follows:

[0094] 5.1 Seed disinfection

[0095] The specific operation of seed disinfection is the same as that in Example 2.

[0096] 5.2 Strain inoculation

[0097] The specific operation of strain inoculation is the same as that in Example 4.

[0098] 5.3 Results Analysis

[0099] like Fig.11 The results showed that inoculation with TYQ6 significantly promoted the development and growth of plant height and stem thickness of cucumber plants, increasing by 6.00% and 92.31% respectively. In addition, it also promoted the accumulation of cucumber substances, and the fresh weight of the aboveground part and the fresh weight of the underground part increased significantly by 27.42% and 30.25%. At the same time, principal component analysis was used to reduce the dimension of each index. In dimension 1, which accounted for 62% of the representativeness of each index, the scores of TYQ6 and the control were 1.20 and -1.32, respectively. From the above results, it can be concluded that the participation of the TYQ6 strain has a certain promoting effect on plant growth.

[0100] Example 6

[0101] TYQ6 assists cucumber seedlings in tolerance to drought.

[0102] Using cucumber seedlings as test materials, drought treatment was applied to cucumber seedlings through pot experiments to analyze the effect of TYQ6 on improving the drought resistance of cucumber seedlings. The specific implementation plan is as follows:

[0103] 6.1 Seed disinfection

[0104] The specific operation is the same as that in Example 2.

[0105] 6.2 Strain inoculation

[0106] The specific operation is the same as that of Example 4.

[0107] 6.3 Imposing drought

[0108] After inoculation with TYQ6, when the seedlings were at the three-leaf and one-heart stage, drought treatment was applied to the seedlings. The specific implementation method was: stop watering the seedlings for one week, and collect data when the leaves of the seedlings wilted significantly.

[0109] 6.4 Results Analysis

[0110] Depend on Fig.12 and Fig.13 It can be seen that under drought treatment, the aboveground and underground fresh weights of cucumber seedlings inoculated with TYQ6 were significantly higher than those of the control, that is, TYQ6 can help maintain the water content of the aboveground part of cucumber seedlings under drought stress. In addition, TYQ6 inoculation can significantly reduce the ion permeability of leaves, indicating that TYQ6 inoculation reduces the damage to the leaf cell membrane under drought treatment. This shows that TYQ6 inoculation improves the drought tolerance of cucumber seedlings.

[0111] Summary: Sphingomonas is a rich new type of microbial resource that can be used for the biodegradation of aromatic compounds. The strains of this genus have great application potential in environmental protection and agricultural production by virtue of their high metabolic capacity and multifunctional physiological characteristics, but the composite functions of this type of bacteria are currently less understood. It can be seen from the above examples that the shell-shaped Sphingomonas TYQ6 used in the present invention has good anti-stress and growth-promoting effects and has broad application prospects in agricultural production. In terms of growth promotion, the strain can significantly promote the growth of cucumber seedlings. When inoculated with TYQ6, the plant height and stem thickness of cucumber plants are significantly promoted, which are increased by 6.00% and 92.31%, respectively. In addition, the accumulation of cucumber substances is also promoted, and the fresh weight of the aboveground part and the fresh weight of the underground part are significantly increased by 27.42% and 30.25%. Under drought stress, TYQ6 inoculation can help cucumber seedlings reduce water loss, maintain the stability of the water content of the plant, and significantly improve the structural stability of mesophyll cells, alleviating the damage of drought stress to plant cell membranes. Under the stress of root-knot nematodes, the number of root knots per unit weight of cucumber seedlings inoculated with TYQ6 was significantly reduced by 30.15% compared with the control, indicating that TYQ6 can effectively help cucumbers resist the infection of root-knot nematodes and is beneficial to the early prevention and control of root-knot nematodes.

[0112] The above are only a few preferred embodiments of the present invention, which are described in a more specific and detailed manner, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A strain of Sphingobacterium crustosum, characterized in that: Sphingobacillus crustosus (Sphingobacterium puteale) strain TYQ6 was deposited in the General Microbiology Center of China Microbiological Culture Collection Administration with the deposit number CGMCC No.27215.

2. A microbial agent, characterized in that: Containing the Sphingobacillus crustosus bacterial cells and / or its fermentation liquid as claimed in claim 1.

3. Use of the bacterium according to claim 1 or the bacterial agent according to claim 2 in preparing a preparation for promoting the growth of cucumber seedlings.

4. Use of the bacterium according to claim 1 or the bacterial agent according to claim 2 in preparing a preparation for enhancing the drought resistance of cucumber seedlings.

5. Use of the bacterium according to claim 1 or the bacterial agent according to claim 2 in preparing a preparation for interfering with the migration of southern root-knot nematodes.

6. Use of the bacterium according to claim 1 or the bacterial agent according to claim 2 in preparing a preparation for controlling southern root-knot nematodes.

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