Sphingosine box bacteria and application thereof

Abstract

The invention relates to the technical field of microorganisms, in particular to sphingosine box bacteria and application thereof. The sphingosine box bacterium capable of effectively degrading panax notoginseng autotoxins, namely saponin and phenolic acid is obtained through separation, the strain can be stably planted at the root of panax notoginseng, root rot pathogenic bacteria of panax notoginseng are inhibited, crude saponin is degraded, new saponin is generated, phenolic acid is degraded, the seedling rate of panax notoginseng and dry weight of panax notoginseng are increased, plant growth and dry matter accumulation are promoted, and the yield of panax notoginseng is increased. The method has very important practical significance for relieving continuous cropping obstacles of panax notoginseng and promoting plant growth.

Description

Technical Field

[0001] The invention relates to the technical field of microorganisms, in particular to a sphingobacterium and an application thereof. Background Art

[0002] Panax notoginseng Panax notoginseng (Burk.) FHChen) is a perennial herbaceous plant of the genus Panax in the Araliaceae family and an important Chinese medicinal material. However, due to the increasing severity of the continuous cropping problem of Panax notoginseng, the land resources suitable for Panax notoginseng cultivation in traditional farmland have been significantly reduced. Root rot is the main manifestation of the continuous cropping problem of Panax notoginseng, and self-toxicity may be the main cause of the formation of continuous cropping problem. Therefore, reducing the accumulation of self-toxic substances such as saponins in the soil of continuous cropping of Panax notoginseng is one of the effective ways to alleviate the continuous cropping problem of Panax notoginseng.

[0003] At present, the main strategies for dealing with this problem include biochar adsorption, crop rotation system and microbial degradation. However, the above measures to reduce self-toxic substances also have their limitations. Specifically, the process of biochar adsorption of self-toxic substances is mainly based on a reversible physical adsorption mechanism, which may cause the adsorbed substances to be released back into the soil environment under certain conditions, thus affecting their long-term effectiveness. On the other hand, although the crop rotation system can effectively alleviate the self-toxic effect, its practical application is often limited by a long implementation cycle, which may be detrimental to the efficient operation of agricultural production. In addition, although the introduction of exogenous microbial strains that can degrade saponin autotoxic substances into continuous cropping soil is regarded as a highly promising biological strategy, it still faces many challenges in practical application. Specifically, the colonization efficiency of these exogenous strains in the soil may not be high, resulting in insufficient survival in the soil, which in turn affects their degradation efficiency. At the same time, even if they are successfully colonized, their degradation efficiency may be affected by multiple factors such as the soil environment and competition from indigenous microorganisms, thus limiting their wide application in actual production. Therefore, in view of the existing challenges in pathogen and autotoxic substance abatement strategies, it has become an urgent need to explore efficient and non-chemical-dependent biological control methods.

[0004] Sphingobacterium Sphingopyxis ) The bacteria's high adaptability to adverse environments gives it a clear advantage in environmental management and it is widely used to degrade organic compounds. Previous studies have shown that strains of this genus can degrade chlorpyrifos, polyethylene glycol, microcystin, 1,2,3-trichloropropane, etc. However, there have been no reports on its ability to degrade notoginseng self-toxic substances - saponins and phenolic acids. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a sphingomyelinase box bacteria ( Sphingopyxis sp. ), which is Sphingobacterium sp. SPX122, and its preservation number is CGMCC No.31092.

[0006] The sphingomyelinase box bacteria SPX122 of the present invention was screened from the rhizosphere soil of Panax notoginseng. The strain was deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration on June 26, 2024. The address of the depository unit is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; Postal Code: 100101, Classification Name: Sphingomyelinase box bacteria Sphingopyxis sp. , the deposit number is CGMCC No.31092.

[0007] Furthermore, the present invention provides a microbial agent, which comprises the Sphingobacterium SPX122.

[0008] Preferably, the microbial agent is a freeze-dried powder of the fermentation broth of Sphingobacterium spX122.

[0009] The fermentation liquid freeze-dried powder contains Sphingobacterium spX122.

[0010] Preferably, the fermentation broth freeze-dried powder also includes a freeze-drying protectant.

[0011] Preferably, the lyoprotectant includes but is not limited to skimmed milk powder, dextrin, lactose, and sucrose.

[0012] Furthermore, the present invention provides the use of the sphingomyelinase or the microbial agent in inhibiting root rot pathogens.

[0013] Preferably, the root rot pathogen is pathogen LD ( Fusarium solani ).

[0014] Preferably, the inhibitory effect on root rot pathogens is improved by using crude notoginseng saponins as a carbon source.

[0015] Furthermore, the present invention provides the use of the sphingosine box bacteria or the microbial agent in regulating the degradation or production of notoginseng crude saponins.

[0016] Furthermore, the present invention provides the use of the sphingosine box bacteria or the microbial agent in improving the survival rate of Panax notoginseng seedlings or the dry weight of Panax notoginseng.

[0017] Furthermore, the present invention provides the use of the sphingobacterium or the microbial agent in degrading phenolic acid.

[0018] Preferably, the phenolic acid is p-hydroxybenzoic acid, ferulic acid, coumaric acid or cinnamic acid.

[0019] Furthermore, the present invention provides the use of the sphingosine box bacteria or the microbial agent in promoting plant growth or dry matter accumulation; preferably, the plant is a plant with continuous cropping obstacles; preferably, the plant is lettuce, tomato, strawberry or soybean.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention isolates and obtains a sphingosine box bacteria that can effectively degrade the autotoxic substances of Panax notoginseng - saponins and phenolic acid. The strain can stably colonize in the roots of Panax notoginseng, inhibit the pathogenic bacteria of Panax notoginseng root rot, degrade crude saponins and generate new saponins, degrade phenolic acid, increase the survival rate of Panax notoginseng and the dry weight of Panax notoginseng, promote plant growth and dry matter accumulation, and has very important practical significance for alleviating the obstacles of continuous cropping of Panax notoginseng and promoting plant growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a photograph of the culture of Sphingobacterium SPX122.

[0022] Figure 2 It is a phylogenetic tree.

[0023] Figure 3 This is a diagram showing the results of identifying the ability of Sphingobacterium SPX122 to produce β-glucosidase.

[0024] Figure 4 This is a graph showing the results of an inhibition experiment of Sphingobacterium spX122 on root rot pathogens.

[0025] Figure 5 It is a growth curve graph of Sphingobacterium SPX122.

[0026] Figure 6 This is a graph showing the seedling survival rate results of an indoor potted plant experiment.

[0027] Figure 7 This is a graph showing the dry weight results of individual plants from an indoor potted plant experiment.

[0028] Figure 8 This is a graph showing the degradation results of crude saponins in the culture medium by Sphingobacterium SPX122.

[0029] Fig. 9 This is a graph showing the degradation results of saponins in continuously cropped soil by Sphingobacterium SPX122.

[0030] Fig.10 This is a graph showing the emergence of Panax notoginseng seedlings under the forest after treatment with Sphingosine Box Fungus SPX122.

[0031] Fig.11 This is a graph showing the degradation of phenolic acid by Sphingobacterium SPX122.

[0032] Fig.12 This is a graph showing the effect of Sphingobacterium spX122 on the growth of lettuce.

[0033] Fig.13 This is a graph showing the effect of Sphingobacterium spX122 on tomato growth.

[0034] Fig.14 This is a graph showing the effect of Sphingobacterium spX122 on strawberry growth.

[0035] Fig.15 This is a graph showing the effect of Sphingobacterium spX122 on soybean growth. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are 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. In statistical analysis, different asterisks represent significant differences, * p <0.05,** p <0.01,*** p <0.001.

[0037] The culture medium formula with crude saponin as the sole carbon source in the following examples is: 3g NaNO3, 1g KH2PO4, 0.5g KCl, 0.5g MgSO4•7H2O, 0.01g FeSO4•7H2O, 10g crude notoginseng saponin, 17g agar, 1000mL distilled water, dissolved, mixed, and adjusted to pH 7.0 with 1mol / L NaOH solution. Crude notoginseng saponin was purchased from Shaanxi Jinkangtai Biotechnology Co., Ltd.

[0038] Example 1 Isolation of Sphingobacterium SPX122 The culture separation method was used to isolate soil microorganisms from the rhizosphere soil of Panax notoginseng stored in a refrigerator at 4°C. Bengal red and PDA culture media were used to isolate fungi, and LB, NA, R2A and modified Gao's medium No. 1 (Wang Luotao et al., 2020; van der Linde et al., 1999; Lin Hong et al., 2012) were used to isolate bacteria. Drawing on the method of culturomics, four culture media, NA, LB, R2A, and PDA, were selected to isolate and culture rhizosphere soil microorganisms of Panax notoginseng. Take different soil samples stored at 4°C, put 1 g of each into a 15 mL sterile centrifuge tube, add 9 mL of sterile distilled water, shake at 120 rpm for 30 min, and let stand for 2 min to make a soil bacterial suspension. Dilute the soil bacterial suspension to 10 with sterile water. 3 , 10 4 and 10 5Times, take 100 μL and add it to the surface of different solid culture media, spread it evenly with a spreader, and culture it in a constant temperature incubator at 28℃. At different culture times such as 3 days to 7 days, pick the single colonies on the corresponding plates and purify them uniformly on NA (bacteria) / PDA (fungus) culture medium. After purification three times, no foreign bacteria appeared, pick the single colony for preservation and sequencing, fungi were subjected to ITS amplification sequencing (Guo Penghao et al., 2012), and bacteria were subjected to 16s rDNA amplification sequencing (Cai et al., 2012). The sequencing results were compared with BLAST in the NCBI database (https: / / www.ncbi.nlm.nih.gov / ).

[0039] A microorganism was isolated and the streak separation photo is shown in the figure. Figure 1 As shown, the bacteria were sequenced by 16S sequencing, and after comparison on the NCBI platform, a phylogenetic tree was constructed, as shown in Figure 2 As shown, the bacteria were identified as Sphingosine Box Sphingopyxis sp. , named as Sphingobacterium SPX122, with the deposit number being CGMCC No.31092.

[0040] Furthermore, the ability to produce β-glucosidase was identified. Esculin is a white needle-shaped crystal, which is hydrolyzed by β-glucosidase produced by microbial metabolism to produce esculin and glucose. Esculin will produce black substances when it encounters iron ions in the culture medium. The test results are shown in Figure 3 , indicating that Sphingobacterium SPX122 can produce β-glucosidase, and CK is the sterile water control group.

[0041] Example 2 Inhibition of pathogens by Sphingobacterium spX122 on crude saponin plates In this example, the inhibition of Sphingobacteria SPX122 on root rot pathogens was observed on plates with different concentrations of crude saponin. Figure 4 As shown, pathogen LD ( Fusarium solani )The colony radius was significantly inhibited in plates with different concentrations of crude saponin, and the inhibition ability increased with the increase of crude saponin concentration. The co-culture experiment of Sphingobacterium spx122 and LD showed that spx122 had a strong antagonistic effect on LD, and with the increase of crude saponin concentration, the colony diameter decreased significantly, indicating that the inhibitory effect of spx122 on LD increased.

[0042] In order to study the degradation effect of Sphingobacterium spx122 on crude saponin, crude saponin was used as the sole carbon source. Figure 4 As shown, crude saponin significantly promoted the growth of Sphingobacterium SPX122, and CK was the sterile water control group.

[0043] Example 3 Crude saponins affect the growth and biofilm formation of Sphingobacterium SPX122 In this example, Sphingosine box bacteria SPX122 was cultured in a culture medium with crude saponin as the sole carbon source. Sphingosine box bacteria SPX122 was cultured in LB medium, and the OD590 value was diluted to ≈0.4 using a microplate reader. 100 μL of bacterial solution was added to 200 mL of liquid culture medium with notoginseng crude saponin as the sole carbon source (10 mg / L of notoginseng crude saponin), and the treatment without bacterial solution was used as a blank control. The culture was placed on a shaker (28°C, 150 r / min), and 200 μL was taken into a 96-well plate every 3 hours. The OD600 was measured with a microplate reader at an absorbance of 600 nm, and a bacterial growth curve was drawn. At the same time, the crystal violet method (Wang Lijun et al., 2019) was used to determine the effect of crude saponin on bacterial biofilm.

[0044] The bacterial growth curve is Figure 5 As shown in the figure, with the extension of culture time, the strain grew, the OD value of the bacterial solution increased, and crude saponin promoted the growth of Sphingobacteria SPX122. This shows that Sphingobacteria SPX122 can tolerate crude saponin, and crude saponin of Panax notoginseng can promote the vegetative growth of the strain and occupy a larger ecological niche in the root system of Panax notoginseng.

[0045] Furthermore, Sphingobacterium spx122 was inoculated into a 96-well plate in a culture medium containing crude saponin as the sole carbon source, and after culturing at 28°C for 52 h, the biofilm content was determined by the crystal violet method, and the OD490 value was read. Figure 5 As shown, the biofilm amount of Sphingobacterium SPX122 was significantly higher than that of CK (0 g / L, sterile water), indicating that crude saponins promoted the biofilm formation of Sphingobacterium SPX122 and enhanced its colonization in the roots of Panax notoginseng.

[0046] Example 4 Effect of Sphingobacterium SPX122 on the Growth of Panax notoginseng Take a certain amount of crude Panax notoginseng saponin, add it to a small pot containing 1 kg of forest soil and mix well, so that the saponin content in the soil is 10 ppm, simulating the total saponin concentration in three-year-old Panax notoginseng soil (Wang Luotao, 2020), let it stand for 3 days for use, and obtain soil with exogenous addition of crude Panax notoginseng saponin. Mix the continuously cropped soil from the greenhouse in Xundian where Panax notoginseng has been planted for three years with the treated unplanted forest soil in a 1:1 ratio, let it stand for 3 days for use, and obtain the continuously cropped soil.

[0047] Select healthy Panax notoginseng seeds and sterilize them with 1.5% NaClO for 5 min, then rinse them with sterile water for 3 times, and dry the surface water with sterile filter paper. There are 10 seeds in each pot, and 10 replicates for each treatment. The laboratory prepared NA liquid culture solution of sphingomyelinase SPX122 to make the OD value of the bacteria ≈0.4. After the seedlings emerged, each pot was irrigated with 50 mL of culture solution (culture solution = 1 part 5 mL bacterial solution: 9 parts sterile water). Sterile water was used as the CK control group. The treatment group included four groups, and the treatment was as follows: the forest soil without Panax notoginseng was collected and divided into two parts, one of which was sterilized with 100℃ steam for 4 hours and set aside after heat dissipation, referred to as sterilization; the other part was not sterilized, referred to as non-sterilization; the two parts of soil were treated again, one of which was added with crude saponin at a concentration of 10 mg / kg, stirred evenly and potted (15 cm diameter flower pot, each pot of soil is about 1 kg) for standby, referred to as saponin; the other part was added with 50% Panax notoginseng continuous soil (Panax notoginseng soil planted for three consecutive years) + 50% of the above-mentioned forest soil (sterilization / non-sterilization), stirred evenly and potted (15 cm diameter flower pot, each pot of soil is about 1 kg) for standby, referred to as 50% continuous. Plant Panax notoginseng seeds. After the potted plants were planted, they were randomly placed in the greenhouse of the Xundian base and routinely managed. The culture solution was irrigated once a week for two consecutive months, and the survival rate of the seedlings was counted. After the Panax notoginseng continued to grow for two months, the potted Panax notoginseng was sampled, cleaned, sterilized at 115℃ for 30 minutes, dried at 60℃ for 3 days, and the dry weight was weighed to calculate the dry weight of each plant.

[0048] The results of the indoor pot test on the survival rate of seedlings are as follows: Figure 6 As shown, Sphingobacterium SPX122 significantly increased the potted seedling survival rate of the four treatments, and the effect was better in continuously cropped soil and non-sterilized soil. This shows that Sphingobacterium SPX122 can promote the growth of Panax notoginseng in soil containing initial microorganisms, especially when saponins are present in the soil. This shows that Sphingobacterium SPX122 can not only degrade saponins, but may also assume the function of recruiting beneficial microorganisms.

[0049] The results of the indoor pot test on dry weight of individual plants are as follows: Figure 7 As shown, Sphingobacterium SPX122 significantly increased the dry weight of individual plants in the four treatments. Sphingobacterium SPX122 can significantly promote the accumulation of dry matter of Panax notoginseng, especially when continuous cropping is used.

[0050] Example 5 Study on the degradation of crude saponins in culture medium by Sphingobacterium SPX122 500 μL of NA culture medium of Sphingobacterium spx122 was added to 50 mL of the sole carbon source culture medium containing 1 g / L crude saponin. After shaking on a shaker at room temperature for 72 h, 2 mL of the liquid was taken and freeze-dried for 48 h (-40 ° C, 0.12 kpa). An equal volume of 75% chromatographic methanol was added to the freeze-dried material to dissolve it, and the pipette tip was blown evenly; 1 mL of the methanol solution was placed in a 1.5 mL centrifuge tube, centrifuged at 14000 rpm for 15 min, and the supernatant was taken for HPLC detection. The contents of 12 saponins (R1, Rg1, Re, Rb1, Rd, Rf, Rb2, Rh1, Rc, Rh2, Rb3 and Rg3) in crude saponins were determined by HPLC. The HPLC detection steps are as follows: (1) HPLC detection conditions are as follows: chromatographic column (4.6 mm×150 mm, 4 µm, Agilent Poroshell 120EC-C18); mobile phase A: acetonitrile; mobile phase B: water; flow rate 1.0 mL / min; column temperature 30°C; detection wavelength 203 nm; injection volume 10 µL. Elution gradient: 0-20 min, 82% B; 20-40 min, 82-57% B; 40-48 min, 57-45% B; 48-54 min, 45% B; 54-56 min, 45-5% B; 56-71 min, 5% B; 71-72 min, 5-82% B; 72-74 min, 82% B. Under these conditions, baseline separation of 12 major saponins can be achieved; (2) Prepare standard solutions of 12 saponins. Accurately weigh the corresponding standard products into a 2 mL volumetric flask and dilute the solution with methanol in a certain proportion to prepare 5 ppm, 10 ppm, 25 ppm, 50 ppm, 100 ppm, 200 ppm and 500 ppm standard solutions. Filter the obtained standard solutions with a 0.22 μm filter membrane for later use; (3) Determination of linear relationship: HPLC was used for detection, and a standard curve was drawn with the chromatographic peak area (Y) as the ordinate and the sample concentration (X) as the abscissa.

[0051] (4) Weigh 0.2 g of crude saponin and dissolve it in 75% chromatographic methanol. Ultrasonicate for 30 min and centrifuge at 10,000 rpm for 10 min. Filter the solution with a 0.22 μm filter membrane and perform HPLC detection. Calculate the concentration of each monomer saponin in the crude saponin based on the standard curve and calculate the saponin conversion rate based on the concentration of each monomer saponin in the uninoculated bacteria.

[0052] Test results such as Figure 8As shown, after inoculation of Sphingosine box bacteria SPX122, the saponin content in the solution changed, indicating that Sphingosine box bacteria SPX122 had a significant degradation of Panax notoginseng crude saponins, and the total saponin content was significantly lower than that of the blank treatment. The detailed results are as follows. In Sphingosine box bacteria SPX122, the average degradation rates of Re (degradation rate was 107%), Rc (degradation rate was 95.68%), Rg1 (degradation rate was 92.33%), Rf (degradation rate was 53.06%), Rh1 (degradation rate was 50.62%), Rd (degradation rate was 14.52%), Rb1 (degradation rate was 12.55%), R1 (degradation rate was 10.83%) and Rb2 (degradation rate was 4.79%) were also generated, and Rg2 (generation rate was 89.23%) was also generated. In addition, two new saponins were generated in the group treated with Sphingobacterium spx122, namely Rh2 (production concentration was 0.09 mg / g) and Rb3 (production concentration was 1.48 mg / g). The comprehensive analysis results showed that Sphingobacterium spx122 could not only degrade saponins, but also generate new saponins.

[0053] Example 6 Study on the effect of Sphingobacterium SPX122 on the degradation of saponins in continuously cropped soil and the emergence rate of Panax notoginseng under forest In order to detect the role of Sphingobacterium SPX122 in soil, a study on soil saponin degradation was conducted. The soil under the forest planted with Panax notoginseng for three years was selected for bacterial treatment. The detailed treatment was as follows: the NA liquid culture medium of Sphingobacterium SPX122 was prepared in the laboratory and shaken to make the OD value of the bacteria ≈0.4, and then the 200 mL / m 3 The soil under the continuous cropping forest was irrigated with a certain amount of bacteria. After irrigation, the treated soil was turned and mixed evenly. The treatment was carried out once a week for 8 consecutive irrigations for a total of two months. Before each treatment, the soil was taken for quantitative analysis of soil saponins and the saponin degradation rate was calculated.

[0054] The results are as follows Fig. 9As shown in the figure (CK represents the sterile water treatment group, 3-3 represents the Sphingosine Box Bacteria SPX122 treatment group), Sphingosine Box Bacteria SPX122 has different degrees of degradation on the five main saponins in the continuous cropping soil of Panax notoginseng. Among them, in the degradation of R1, the degradation effect of Sphingosine Box Bacteria SPX122 was significantly higher than that of CK in the later stage; in the degradation of Rg1, the degradation trend was similar to that of R1, but the phenomenon that Sphingosine Box Bacteria SPX122 treatment was significantly higher than CK began in the second week after treatment, earlier than R1 (4-5 weeks); in the degradation of Rb1, Sphingosine Box Bacteria SPX122 was at The degradation effect of soil saponins after treatment was significantly higher than that of CK. In the degradation of Rd, the degradation effect of Sphingobacterium SPX122 after treatment was significantly higher than that of CK, and this difference was more obvious in the early stage of treatment. In the degradation of Re, the treatment of Sphingobacterium SPX122 was significantly higher than that of the control in the later stage. The comprehensive results of five saponins showed that Sphingobacterium SPX122 was significantly higher than CK after treatment for a period of time. The soil saponin degradation effect clearly demonstrated the ability of Sphingobacterium SPX122 to degrade saponins, providing important evidence for the study of the degradation ability of Sphingobacterium SPX122.

[0055] Furthermore, the soil treated two months later was used to plant one-year-old seven-seed strips and Panax notoginseng seeds under the forest to study the emergence of Panax notoginseng seedlings under the forest after treatment with sphingomyelinase SPX122. The results showed that ( Fig.10 ), Sphingobacterium SPX122 treatment significantly increased the emergence rate of two-year-old Panax notoginseng under the forest. In the emergence of one-year Panax notoginseng, the Sphingobacterium SPX122 treatment group was slightly higher than the control (CK is the sterile water control group), but there was no significant difference. Therefore, in the understory environment, Sphingobacterium SPX122 treatment can significantly increase the emergence rate of one-year and two-year Panax notoginseng, and the effect is more significant in promoting two-year Panax notoginseng, indicating that Sphingobacterium SPX122 has greater application potential in actual production.

[0056] Example 7 Degradation effect of Sphingobacterium SPX122 on phenolic acid Numerous research reports show that the high adaptability of Sphingopyxis bacteria to adverse environments gives them a clear advantage in environmental management and they are widely used to degrade organic compounds. Previous studies have shown that strains of this genus can degrade chlorpyrifos, polyethylene glycol, microcystin, 1,2,3-trichloropropane, etc. However, there are few studies on the degradation of plant autotoxic substances by this bacterium. In the growth of Panax notoginseng, the autotoxic substances include phenolic acid in addition to saponins. This example tests the degradation effect of Sphingopyxis SPX122 on phenolic acid.

[0057] The soil was treated with Sphingobacterium spX122 for two consecutive months, and sterile water was used as the control group (CK). The soil was irrigated once a week, and the OD value of the bacterial solution was 0.6 each time, and 50 ml was used each time. The initial content and final content of the four phenolic acids in the soil were detected by absolute quantitative analysis. The degradation effects of bacteria on the four main phenolic acids in the soil are summarized as follows ( Fig.11 ), in p-hydroxybenzoic acid, the average degradation rate of CK was 5.03%, and after treatment with Sphingobacteria SPX122, the average degradation rate was 25.62%; in ferulic acid, the average degradation rate of CK natural degradation was 13.50%, and the average degradation rate of Sphingobacteria SPX122 was 12.67%, but there was no significant difference between the two treatments; in p-coumaric acid, the average degradation rate of CK was 2.40%, and the average degradation rate after treatment with Sphingobacteria SPX122 was 4.76%; in cinnamic acid, the average degradation rate of CK was 1.44%, and the average degradation rate after treatment with Sphingobacteria SPX122 was 0.99%. Therefore, among the four phenolic acid treatments, the total degradation rate of CK on the four phenolic acids in soil was 5.02%, and the total degradation rate of Sphingobacteria SPX122 was 15.04%. Comprehensive analysis showed that Sphingobacterium SPX122 could significantly degrade phenolic acids in the soil, but there were differences in the degradation ability for different phenolic acids. Sphingobacterium SPX122 had a stronger ability to degrade total phenolic acids.

[0058] Example 8 Effect of Sphingobacterium SPX122 on Plant Growth 1. Effect of Sphingobacterium spX122 on lettuce growth In order to explore the effect of treatment with Sphingosine Box Fungus SPX122 on plant growth, lettuce, which is sensitive to phenolic acid, was selected for growth measurement. Lettuce seeds were planted in soil treated with Sphingosine Box Fungus SPX122 (treatment method is the same as Example 7) for two months, and the survival rate of lettuce, fresh weight per plant, dry weight per plant and root growth were counted.

[0059] The results show that ( Fig.12 ), there was no significant difference in the survival rate of lettuce after treatment with Sphingosine Box Bacteria SPX122; the fresh weight and dry weight of lettuce per plant were significantly increased after treatment with Sphingosine Box Bacteria SPX122; the root length, root surface area and root volume of lettuce were increased after treatment with Sphingosine Box Bacteria SPX122, but there was no significant difference between the treatment groups and CK (sterile water treatment group). Therefore, the soil treated with Sphingosine Box Bacteria SPX122 promoted the growth of lettuce and the accumulation of dry matter.

[0060] 2. Effects of Sphingobacterium spX122 on tomato growth Studies have shown that phenolic acids affect the growth of tomato seedlings. Therefore, tomatoes were selected for growth measurement. Tomato seeds were planted in soil treated with Sphingobacterium spX122 (treatment method is the same as Example 7) for two months, and the survival rate of tomatoes, fresh weight per plant, dry weight per plant and root growth were counted.

[0061] The results show that ( Fig.13 ), Sphingobacterium SPX122 significantly increased the survival rate of tomato seedlings; the fresh weight and dry weight of individual plants after Sphingobacterium SPX122 treatment were slightly higher than those of CK, but there was no significant difference; Sphingobacterium SPX122 treatment increased the growth of root length, root diameter, root surface area and root volume of lettuce, but there was no significant difference between CK and CK. Therefore, the soil treated with Sphingobacterium SPX122 promoted the growth of tomato and the accumulation of dry matter.

[0062] 3. Effects of Sphingobacterium spX122 on strawberry growth Studies have shown that the accumulation of phenolic acid in the soil is an important cause of strawberry continuous cropping problems. In order to study the degradation of phenolic acid by Sphingobacterium SPX122, strawberries were selected for potted verification. Strawberry seedlings were transplanted into the soil treated (the treatment method was the same as in Example 7) for two months. After differences in growth appeared, the survival rate, fresh weight of a single plant, dry weight of a single plant and the growth of new roots were counted.

[0063] The results show that ( Fig.14 ), Sphingobacterium SPX122 significantly increased the survival rate of strawberry seedlings; Sphingobacterium SPX122 significantly increased the fresh weight and dry weight of the aboveground part of strawberry; but there was no significant difference in root system indicators. Therefore, Sphingobacterium SPX122 promoted the survival rate of strawberry seedlings and the growth of the aboveground part.

[0064] 4. Effects of Sphingobacterium spX122 on soybean growth Studies have shown that the accumulation of phenolic acid in the soil affects the growth of soybean seedlings. Therefore, soybeans were selected for potted plant verification. Soybean seeds were planted in the soil treated (treatment method is the same as in Example 7) for two months. After the growth showed differences, the survival rate of seedlings, fresh weight per plant, dry weight per plant and the growth of new roots were counted. The results showed that ( Fig.15 ), there was no significant difference in the survival rate of soybean after treatment with Sphingosine Box Bacteria SPX122 and CK; Sphingosine Box Bacteria SPX122 treatment significantly increased the fresh weight of soybean plants aboveground, dry weight of plants, fresh weight of plants underground and dry weight of plants; Sphingosine Box Bacteria SPX122 treatment significantly increased the growth of root surface area, root diameter and root volume in the root system. Therefore, Sphingosine Box Bacteria SPX122 promoted the growth of soybean.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Sphingobacterium Sphingopyxis sp. ), characterized in that, It is Sphingobacterium sp. SPX122, and its deposit number is CGMCC No.31092.

2. A microbial agent, characterized in that: It comprises the Sphingobacterium SPX122 according to claim 1.

3. The microbial agent according to claim 2, characterized in that: The microbial agent is freeze-dried powder of fermentation liquid of Sphingobacterium spX122.

4. The microbial agent according to claim 3, characterized in that: The fermentation broth freeze-dried powder also includes a freeze-drying protectant.

5. Use of the sphingomyelinase according to claim 1 or the microbial agent according to any one of claims 2 to 4 in inhibiting root rot pathogens.

6. The use according to claim 5, characterized in that: The inhibitory effect on root rot pathogens is improved by using notoginseng crude saponins as a carbon source.

7. Use of the sphingomyelinase described in claim 1 or the microbial agent described in any one of claims 2 to 4 in regulating the degradation or production of crude notoginseng saponins.

8. Use of the sphingosine box bacteria according to claim 1 or the microbial agent according to any one of claims 2 to 4 in improving the survival rate of Panax notoginseng or the dry weight of Panax notoginseng.

9. Use of the sphingomyelinase according to claim 1 or the microbial agent according to any one of claims 2 to 4 in degrading phenolic acid; Preferably, the phenolic acid is p-hydroxybenzoic acid, ferulic acid, coumaric acid or cinnamic acid.

10. Use of the sphingobacterium according to claim 1 or the microbial agent according to any one of claims 2 to 4 in promoting plant growth or dry matter accumulation; preferably, the plant is a plant that is hindered by continuous cropping; preferably, the plant is lettuce, tomato, strawberry or soybean.

Images