Ginseng earthy yellow soil-source bacterium and application thereof

Abstract

The invention belongs to the field of microorganisms, and relates to a ginseng earthy yellow soil-source bacterium and application thereof, the microbiological classification name of the ginseng earthy yellow soil-source bacterium is Flavissolibacillus, the ginseng earthy yellow soil-source bacterium is preserved in the China General Microbiological Culture Collection Center on July 24, 2025, and the preservation number is CGMCC No.35360. The ginseng earthy yellow soil-source bacterium has the advantages that the ginseng earthy yellow soil-source bacterium can be used for preparing the ginseng earthy yellow soil-source bacterium; the invention provides a ginseng earthy yellow soil-source bacterium capable of inhibiting or relieving allelopathy caused by buckwheat planting and promoting agricultural production and application of the ginseng earthy yellow soil-source bacterium.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microorganisms, and relates to a kind of bacteria and application, especially to a kind of ginseng soil yellow soil source bacteria and application. BACKGROUND

[0002] Buckwheat (Fagopyrum sp.) is an important economic crop of Polygonaceae Fagopyrum, which is widely welcomed due to its balanced amino acid composition and rich resistant starch, vitamins, trace elements and antioxidants. The most widely cultivated varieties are sweet buckwheat (Fagopyrum esculentum Moench.) and tartary buckwheat (Fagopyrum tataricum Gaertn.). However, in buckwheat production practice, the after-crop (whether continuous cropping or rotation) often shows different degrees of growth inhibition and yield reduction. For example, under the condition of no fertilization, buckwheat continuous cropping reduces the soil nitrogen, phosphorus, potassium content, and enzyme activity and reduces grain yield; continuous cropping also affects the growth of tartary buckwheat seedlings, and different varieties respond differently to continuous cropping obstacles. Studies have shown that this inhibitory effect may be related to the allelopathy of buckwheat root exudates: small molecules in its exudates can significantly induce maize root edge cell apoptosis; can change the root system architecture of Amaranthus retroflexus, reducing total root length, volume, surface area, root tip number and bifurcation number; in addition, tartary buckwheat water extract also has an inhibitory effect on the seed germination and seedling growth of Digitaria sanguinalis and Bidens pilosa. Although buckwheat has a general inhibitory effect on the after-crop, whether the root exudates directly inhibit crop growth, whether the allelopathic effects of different buckwheat varieties differ, and the key rhizospheric allelochemicals that cause inhibition, still need to be clarified.

[0003] Soil microorganisms play an important role in alleviating allelopathy, and using microorganisms to improve crop yield and promote plant growth is a current research hotspot. A large number of studies have confirmed the microorganism's ability to degrade allelochemicals: for example, Acinetobacter suaedae screened from the rhizosphere soil of Suaeda salsa can simultaneously degrade phenolic acids (p-hydroxybenzoic acid, coumaric acid) and alkane substances, and the coexisting substrates promote each other's degradation efficiency by regulating gene expression; Pseudomonas strains with p-coumaric acid as the sole carbon source screened from the rhizosphere soil of bamboo and pine can effectively degrade ferulic acid, p-hydroxybenzoic acid and p-hydroxybenzaldehyde; Pseudomonas putida KT2440 can degrade various phenolic acids such as gallic acid, ferulic acid and coumaric acid. Therefore, screening functional microbial resources with broad-spectrum substrate degradation ability, and verifying their effect in degrading harmful substances or promoting plant growth under simulated natural conditions and actual production, are the future research directions. However, there is currently no research report on the degradation of allelochemicals by buckwheat rhizosphere microorganisms (single or complex). Whether buckwheat rhizosphere microorganisms can degrade allelochemicals to alleviate the inhibitory effect, and the specific functional strains with degradation potential, are still unclear. SUMMARY

[0004] In order to solve the above technical problems in the background art, the present application provides a ginseng soil yellow soil source bacterium capable of inhibiting or relieving allelopathy caused by buckwheat planting and promoting agricultural production, and an application thereof.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A ginseng soil yellow soil source bacterium, characterized in that: the microbiological classification of the ginseng soil yellow soil source bacterium is named Flavisolibacter ginsengisoli, and the ginseng soil yellow soil source bacterium has been preserved in the China General Microbiological Culture Collection Center on July 24, 2025, and the preservation number is CGMCC No. 35360.

[0007] Application of the ginseng soil yellow soil source bacterium as described above in relieving or weakening allelopathy caused by plant planting.

[0008] Application of the ginseng soil yellow soil source bacterium as described above in relieving or weakening allelopathy caused by buckwheat planting.

[0009] Application of the ginseng soil yellow soil source bacterium as described above in relieving or weakening allelopathy caused by buckwheat continuous planting or rotation planting.

[0010] Application of the ginseng soil yellow soil source bacterium as described above in degrading allelochemicals produced by buckwheat continuous planting or rotation planting.

[0011] The allelochemical is benzoic acid, especially 2-(Formylamino)benzoic acid.

[0012] An auxiliary additive for buckwheat planting obtained based on the application as described above.

[0013] An auxiliary additive for buckwheat planting, characterized in that: the auxiliary additive comprises the ginseng soil yellow soil source bacterium as described above and an agricultural planting-acceptable carrier.

[0014] The auxiliary additive is a bacterium liquid, a bacterium suspension, a fermentation product, a bacterium fertilizer and / or a liquid fertilizer; the effective viable bacteria of the ginseng soil yellow soil source bacterium in the auxiliary additive are not less than 6x10 6 CFU / mL.

[0015] The present application has the following advantages:

[0016] The present application provides a ginseng soil yellow soil source bacteria, the microbiological classification of which is named Flavisolibacter ginsengisoli, which has been preserved in CGMCC on July 24, 2025, and the preservation number is 35360. The present application is to isolate a Flavisolibacter ginsengisoli strain FG1 from the rhizosphere soil of tartary buckwheat, which can efficiently utilize 2-(Formylamino)benzoic acid as the only carbon source and energy source for growth, and the decrease of the concentration of 2-(Formylamino)benzoic acid indicates that the strain has the ability to degrade allelochemicals. In addition, the in-dish growth promotion test can prove that while adding allelochemicals to inhibit the germination of corn seeds (the radicle and plumule are significantly shortened), the inoculation of FG1 strain can significantly alleviate this inhibition, and the length of radicle and plumule is significantly higher than that of the treatment group (M) with only allelochemicals added. Although its growth index does not reach the level of sterile water control (C), it can be shown that FG1 effectively alleviates the inhibition of buckwheat planting on the early growth of corn by degrading allelochemicals, which has a significant promoting effect on agricultural production. Obviously, the present application clearly shows the inhibitory effect of tartary buckwheat and sweet buckwheat root exudates on the growth and development of corn, and compares the difference in inhibitory intensity between the two; at the same time, the key allelochemicals common to tartary buckwheat and sweet buckwheat are identified, and the inhibitory effect of specific allelochemicals on corn is verified; in addition, based on the analysis of rhizosphere microbial community changes by amplicon sequencing, potential degrading functional microorganisms are explored, and the degradation ability of the target strain to allelochemicals and the effect of alleviating the inhibition of corn growth are verified. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the influence of sterilized and unsterilized soil after planting different buckwheat on the growth of corn seedlings and the influence of different buckwheat rhizosphere water culture solution on the growth of corn seeds;

[0018] Figure 2 It is the screening of allelochemicals secreted by buckwheat rhizosphere based on metabolomics;

[0019] Figure 3 It is the screening of allelochemicals degrading strains in buckwheat rhizosphere based on metagenomics;

[0020] Figure 4 It is the verification test diagram of the degradation ability of the Flavisolibacter ginsengisoli strain FG1 provided by the present application. DETAILED DESCRIPTION

[0021] The technical solutions provided by the present application will be described in detail below in combination with the drawings:

[0022] Preparation of the test: buckwheat field planting and soil collection

[0023] Buckwheat rhizosphere soil (0-20 cm) used in the present application was collected from buckwheat planting field in Li village, Hujiamiao town, Chunhua county, Xianyang city, Shaanxi province (34°48'N, 108°34'E). Buckwheat field experiment was set up with three treatments: no planting buckwheat (CK), planting sweet buckwheat (TQ) and planting bitter buckwheat (KQ). The plot used randomized block design, 3 repeated plots for each treatment, and each plot area was 399.50 m 2 . The planted bitter buckwheat variety was Xinong 9940, and the sweet buckwheat variety was Yuliao No. 4 (both purchased from Hongsheng small grain professional cooperative in Qiaogouwan township, Jingbian county). Buckwheat was planted from July to October in 2023, and the sampling time was the harvest period (October). Five-point sampling method was used to collect soil samples in the plough layer (0-20 cm) of each plot, and then the soil samples of the three repeated plots were thoroughly mixed and passed through a 20-mesh sieve to remove obvious plant roots, animal carcasses and other residues. The CK treatment directly collected 0-20 cm soil from each point and mixed the samples.

[0024] Example 1 Allelopathy inhibits corn growth pot verification test

[0025] To explore the direct inhibitory effect of soil root exudates on corn growth, the effects of soil under different treatments on corn growth under sterilization and non-sterilization conditions were compared by pot experiment. The field-collected soil of each treatment was irradiated for sterilization (irradiation dose was 25 kGy). The pot experiment was set up with 6 treatments: US_CK, soil without planting buckwheat; US_KQ, soil after planting bitter buckwheat; US_TQ, soil after planting sweet buckwheat. S_CK, sterilized soil without planting buckwheat; S_KQ, sterilized soil after planting bitter buckwheat; S_TQ, sterilized soil after planting sweet buckwheat. Full-grain corn seeds were selected, disinfected with 70% alcohol for 30 s, and rinsed with distilled water for 5 times. Then the surface-sterilized seeds were first placed in a culture dish with filter paper and placed in a 26℃ incubator for dark germination. After three days, the uniform and consistent seedlings after germination were transplanted into pots containing 500 grams of soil of each treatment (bottom diameter 8 cm, top diameter 10 cm, height 10 cm), and placed in a culture room (temperature 25℃, 16h light / 8h dark, light intensity 8000 Lux, relative humidity 60%). Each pot was planted with one corn seedling, and 12 biological replicates were set. After one month, the plants were collected to determine the growth indicators.

[0026] The results are shown in Figure 1 , in Figure 1 , in Figure 1AF represent maize growth indicators under unsterilized soil treatments (US) and sterilized soil treatments (S) after planting different types of buckwheat. CK represents soil without buckwheat planting; KQ represents bitter buckwheat soil; and TQ represents sweet buckwheat soil. All data are expressed as mean ± standard error, and different letters above the error bars indicate significant differences between treatments (P < 0.05; T-test). Pot experiment results showed that in the unsterilized soil treatment ( Figure 1 In the treatment of tartary buckwheat (US_KQ), the plant height, dry weight, root length, root surface area, root volume, and average root diameter of maize were significantly lower than those of the control (US_CK) (P<0.05); the plant height, dry weight, and root volume of sweet buckwheat (US_TQ) were also significantly lower than those of the control (P<0.05). In the sterilized soil treatment ( Figure 1 A- Figure 1 F), all maize growth indices (including plant height, dry weight, root length, root surface area, root volume, and root average diameter) treated with tartary buckwheat (S_KQ) and sweet buckwheat (S_TQ) were significantly lower than those of the control (S_CK) (P<0.05). Quantitative analysis revealed that compared to the control soil: sterilized tartary buckwheat soil (S_KQ) reduced maize growth indices by 12.42% to 49.26%, and unsterilized soil (US_KQ) by 5.14% to 33.16%; sterilized sweet buckwheat soil (S_TQ) reduced them by 6.53% to 24.09%, and unsterilized soil (US_TQ) by 4.23% to 24.58%. These data indicate that: 1) Buckwheat root exudates significantly inhibit corn growth; 2) Tartary buckwheat has a stronger inhibitory effect than sweet buckwheat; 3) The highest inhibition rate of tartary buckwheat in sterilized soil (49.26%) is much higher than that in unsterilized soil (33.16%), suggesting that soil microorganisms in buckwheat cultivation may alleviate allelopathic effects.

[0027] Example 2: Collection of buckwheat root exudates by hydroponics and their effect on maize seed germination

[0028] To exclude the interference of soil factors, further water culture experiments were carried out. The Hoggland nutrient solution commonly used in soilless culture was used for buckwheat water culture. Several sweet buckwheat and bitter buckwheat seeds with normal color, equal size, and plump particles were selected, disinfected with 70% alcohol for 30s, and rinsed with distilled water for 5 times. The seeds were evenly placed in the seedling box with wet germination paper, and placed in a 25℃ artificial climate box for 3d of germination. Buckwheat seeds with similar growth and consistent germination were selected and transplanted into centrifuge tubes containing 50mL Hoggland nutrient solution (1.26g / L), with seedling sponge as the supporting medium. Two seedlings were transplanted into each tube, and 15 biological replicates were set. The transplanted buckwheat seedlings were cultured in an artificial climate box (temperature 25℃, 16h light / 8h dark, light intensity 8000Lux, relative humidity 60%), and the nutrient solution was recovered after 15d for corn dish test. Three treatments were set: KQ, bitter buckwheat water culture solution; TQ, sweet buckwheat water culture solution; CK, sterile water. Each treatment was set with 15 biological replicates, and 10mL of each treatment water culture solution was added, and the same amount of sterile water was added to CK. The culture dishes were placed in a culture box (temperature 25℃, 16h light / 8h dark, light intensity 8000Lux, relative humidity 60%), and the water culture solution was replaced as needed to maintain the humidity and concentration of the filter paper in the culture dish. After 3d of germination, the length of the seed embryo and radicle was measured.

[0029] The results of the water culture experiment are shown in Figure 1 G. Figure 1 G is the appearance of corn seeds under different buckwheat root water culture solution treatments. Figure 1 H- Figure 1 I is the growth index of corn seeds under different buckwheat root water culture solution treatments. Figure 1 In G, H, and I, CK is the buckwheat-free water culture solution; KQ is the bitter buckwheat root water culture solution; TQ is the sweet buckwheat root water culture solution. Both bitter buckwheat (KQ) and sweet buckwheat (TQ) water culture solutions significantly inhibited corn seed germination (compared with the sterile water control CK). KQ treatment significantly reduced the length of corn radicle and embryo by 28.24% and 53.44% respectively (P<0.05), and TQ treatment significantly reduced the length of embryo by 45.04% (P<0.05; Figure 1 H). The results confirmed that buckwheat root exudates directly inhibit the early growth of corn, and the inhibitory effect of bitter buckwheat is significantly stronger than that of sweet buckwheat, consistent with the conclusions of the pot culture experiment.

[0030] Example 3 Extraction and metabolomics analysis of buckwheat rhizosphere soil metabolites

[0031] Take 100 g of rhizosphere soil of KQ, TQ and CK in the field, add 500 mL of deionized water, oscillate and extract for 3 h, then low-temperature centrifuge for 5 min (4°C, 8000 r / min), reserve the supernatant to perform suction filtration, then evaporate water; add methanol to dissolve the residue, wait for methanol to evaporate, repeatedly wash 2-3 times with 5 mL of methanol, and then filter with a microporous filter membrane (0.22 μm pore size) to be stored in a sample bottle for LC-MS / MS detection. Three repetitions are set for each treatment.

[0032] The data acquisition instrument system mainly includes ultra performance liquid chromatography (UPLC) (Exion LC™ AD, https: / / sciex.com.cn / ) and tandem mass spectrometry (MS / MS). The liquid phase conditions mainly include: (1) chromatographic column: Agilent SB-C18 1.8 um, 2.1 mm*100 mm; (2) mobile phase: A phase is ultrapure water (add 0.1% formic acid), B phase is acetonitrile (add 0.1% formic acid); (3) elution gradient: 0.00 min B phase ratio is 5%, 9.00 min B phase ratio linearly increases to 95%, and maintains at 95% 1 min, 10.00-11.10 min, B phase ratio decreases to 5%, and balances at 5% to 14 min; (4) flow rate 0.35 mL / min; column temperature 40℃; injection volume 2 μL. The mass spectrometry conditions mainly include: electrospray ion source (ESI) temperature 500℃; ion spray voltage (IS) 5500V (positive ion mode) / -4500V (negative ion mode); ion source gas I (GSI), gas II (GSII) and curtain gas (CUR) are set to 50, 60 and 25 psi respectively, and the collision-induced ionization parameter is set to high. QQQ scan uses MRM mode, and the collision gas (nitrogen) is set to medium. Through further optimization of declustering potential (DP) and collision energy (CE), the DP and CE of each MRM ion pair are completed. According to the metabolites eluted in each period, a specific group of MRM ion pairs is monitored in each period. Based on the local metabolic database, the metabolites of the sample are subjected to mass spectrometry qualitative and quantitative analysis. The characteristic ions of each substance are screened by triple quadrupole, and the signal intensity (CPS) of the characteristic ions is obtained in the detector. The sample is opened by MultiQuant software to obtain the mass spectrum file, and the chromatographic peak is integrated and corrected. The peak area (Area) of each chromatographic peak represents the relative content of the corresponding substance, and finally all chromatographic peak area integration data are saved. Use the MetaboAnalyst R package in R software to perform OPLS-DA analysis. Based on the P-value and fold change value of univariate analysis, further screen out the differential metabolites. Select the metabolites with fold change ≥1.2 and P<0.05 between KQ, TQ and CK groups as significant differential metabolites. Based on the random forest model, select the metabolites with the highest contribution to the prediction accuracy of sample grouping.

[0033] A total of 472 metabolites were identified in all buckwheat rhizosphere soil samples. Orthogonal partial least squares discriminant analysis (OPLS-DA) results showed that CK, KQ and TQ samples were significantly separated on principal components PC1 and PC2 Figure 2 A, OPLS-DA analysis of different buckwheat rhizosphere soils), indicating significant differences in soil metabolite composition between different treatment groups. According to chemical classification statistics, the highest proportion of identified metabolites was lipids (20.13%), followed by amino acids and their derivatives (13.98%), alkaloids (10.81%), phenolic acids (9.11%), terpenes (8.47%), organic acids (8.05%), flavonoids (6.99%), nucleotides and their derivatives (5.30%), lignin and coumarin (2.33%), and quinones (0.85%) Figure 2 B, Metabolite classification pie chart).

[0034] Based on the above threshold screening results: KQ and TQ rhizosphere soil compared with CK, and KQ vs TQ group, the types and abundances of differential metabolites were different Figure 2 C). There were 17 substances with significant differences in abundance in the TQ vs CK group; 5 substances with significant differences in abundance in the KQ vs CK group; and 2 substances with significant differences in abundance in the KQ vs TQ group (fold-change≥1.2, P<0.05). 2-(Formylamino)benzoic acid was common in the three groups. Further random forest analysis and three-fold cross-validation showed that the cross-validation error curve tended to be stable at the 17th metabolite, and 2-(Formylamino)benzoic acid was present in the 17th substance and contributed the most in KQ Figure 3 D). Therefore, 2-(Formylamino)benzoic acid was selected as the key allelochemical for subsequent allelopathy verification.

[0035] The invention focuses on two widely cultivated buckwheat varieties, sweet buckwheat and bitter buckwheat. According to the results of pot and hydroponic experiments, the root exudates of bitter buckwheat and sweet buckwheat can inhibit the growth and development of corn, and the inhibitory effect of bitter buckwheat is significantly stronger than that of sweet buckwheat. Field studies have shown that buckwheat reduces weed biomass compared to plots without buckwheat; laboratory studies have shown that root exudates inhibit the growth of weed roots and shoots and reduce weed dry weight. Perennial buckwheat has been shown to significantly inhibit plant growth and the identified chemicals are some phenolic acids. Through rhizosphere soil metabolomics analysis combined with strict screening methods (OPLS-DA, fold-change threshold, random forest analysis), the invention determines that 2-(Formylamino)benzoic acid is a key substance closely related to the allelopathy of buckwheat (especially bitter buckwheat).

[0036] Example 4 Test of the effect of exogenous addition of 2-(Formylamino)benzoic acid on corn growth

[0037] Corn seeds were surface sterilized in 70% alcohol for 30s and rinsed with distilled water 5 times. After surface sterilization, the seeds were first placed in a culture dish with filter paper and placed in a 26°C incubator for dark germination. After three days, uniform and consistent seedlings were selected and transplanted into pots containing 500g of soil (8cm in diameter at the bottom, 10cm in diameter at the top, 10cm high), and placed in a culture room (temperature 25°C, 16h light / 8h dark, light intensity 8000Lux, relative humidity 60%). Each pot was planted with one corn seedling, and 15 biological replicates were set for each treatment. Different concentrations of exogenous 2-(Formylamino)benzoic acid solution 25mL were added to the potting soil to maintain the concentration. The addition frequency was maintained every 5d. 2-(Formylamino)benzoic acid solution was set at three treatment concentrations: CK (0μM), T1 (1000μM), T2 (100μM), T3 (10μM). At the same time, 25mL tap water was used as a control, and after 1 month of cultivation, destructive sampling was performed for the determination of the corresponding indicators.

[0038] The results show that exogenous addition of allelochemical 2-(Formylamino)benzoic acid has a significant concentration-dependent inhibitory effect on the growth indicators of corn plants (P<0.05), as shown in Figure 2 E- Figure 2The results are shown in Figure J (growth indices of maize plants treated with different concentrations of exogenously added 2-(Formylamino)benzoic acid (P<0.05; one-way ANOVA, Tukey's HSD). Specifically, at a concentration of 1000 μM, multiple growth indices of maize seedlings (fresh weight, chlorophyll content, root length, root surface area, root volume, and average root diameter) were significantly lower than the control (1000 μM; P<0.05). At a concentration of 100 μM, fresh weight, chlorophyll content, and average root diameter showed significant differences from the control, while other indices showed no significant differences (P<0.05). At a concentration of 10 μM, except for chlorophyll content, other indices showed no significant differences from the control (P<0.05). These results indicate that the exogenous addition of the allelochemical 2-(Formylamino)benzoic acid can inhibit the growth and development of maize to a certain extent. This invention verified the inhibitory effect of this allelochemical through exogenous addition experiments: the allelochemical 2-(Formylamino)benzoic acid... Acid exhibits a concentration-dependent inhibitory effect on maize seedling growth (fresh weight, chlorophyll, root morphology, and physiological and biochemical indicators).

[0039] Example 5: Amplicon Sequencing and Data Analysis

[0040] Take 0.5g of rhizosphere soil samples from KQ, TQ, and CK fields, and use... Genomic DNA was extracted using the Soil DNA Kit (Omega Bio-tek). DNA integrity and purity were assessed using 1% agarose gel electrophoresis, while DNA concentration and purity were determined using NanoDropOne (Thermo Fisher Scientific, MA, USA). The V4-V5 region of the bacterial 16S rRNA gene was amplified by PCR using universal primers 515F (GTGCCAGCMGCCGCGGTAA) and 907R (CCGTCAATTCMTTTRAGTTT). After comparing the concentrations of the PCR products using GeneTools Analysis Software (Version 4.03.05.0, SynGene), the required volume for each sample was calculated according to the principle of equal mass, and the PCR products were then mixed. The Gel Extraction Kit was used to recover PCR mixtures, and the target DNA fragments were recovered by elution with TE buffer. Subsequent library construction was performed according to... Ultra TM IIDNA Library Prep Kit for (New England Biolabs, MA, USA) standard procedure, and after completion, the library was sequenced on the Illumina sequencing platform. The raw image data file obtained by sequencing was converted into raw sequencing sequence (Raw Reads) through base calling analysis, and the results were stored in FASTQ (abbreviated as fq) file format, which contains sequence information and corresponding sequencing quality information of the sequencing sequence (Reads).

[0041] Based on the OTU abundance table, the alpha diversity metrics (Shannon and Simpson) were estimated by Mothur, v1.30.160. The similarity between samples was arranged according to PCoA, based on Euclidean distance, using Vegan v2.5-3 (https: / / CRAN.R-project.org / package=vegan / ) for multivariate analysis of variance to evaluate the percentage of variation explained by treatment events and its statistical significance. LEfSe was used to identify differentially abundant bacterial taxa at the genus level between different treatment groups (LDA>2). Kruskal_Wallis rank sum test was used to test the significance of differences in bacterial genera among the three groups of treatments (P<0.05).

[0042] In order to explore the changes of buckwheat rhizosphere microbial diversity and screen potential microorganisms capable of degrading allelochemicals, 16S rRNA gene amplicon sequencing analysis was performed. Shannon index and Simpson index were used to evaluate the Alpha diversity of rhizosphere soil bacteria before and after phytoremediation. See Figure 3 , the results showed that the Shannon index increased significantly after planting buckwheat (results as shown in Figure 3 A), and the Simpson index decreased significantly (results as shown in Figure 3 B, Figure 3 A and Figure 3 B are the Alpha diversity of different buckwheat rhizosphere bacterial communities, respectively), indicating that the species richness and evenness of rhizosphere soil bacteria have improved. Principal coordinate analysis (PCoA) showed that the samples of buckwheat planting treatment and non-buckwheat planting control (CK) were obviously separated in community composition (results as shown in Figure 3 C, principal coordinate analysis of different buckwheat rhizosphere bacterial communities); the two principal coordinate axes explained 69.8% of the variation, of which PC1 contributed 62.7% and PC2 contributed 7.1%.

[0043] Differential species between KQ and CK groups at genus level were identified by LEfSe analysis. The common bacterial genera with LDA value greater than 2 in KQ and TQ groups were Flavisolibacter, Cavicella, IMCC26134, Adhaeribacter, Nibribacter, Aliihoeflea, Microvirga, Rhodococcus, Geminicoccus, Aridibacter, Gemmata, Oligoflexus and Leptolyngbya_EcFYyyy_00. The results are shown in Figure 3 D (LDA discriminant column chart of LDA>2; P<0.05) of rhizosphere soil bacterial community of tartary buckwheat. Among them, Flavisolibacter has the highest abundance in KQ treatment; Candidatus_Nitrososphaera has the highest abundance in KQ treatment group. The results are shown in Figure 3 E (LDA discriminant column chart of LDA>2; P<0.05) of rhizosphere soil bacterial community of sweet buckwheat. The differential genera with the highest abundance in CK treatment are Aquicella, Acidibacter and Zavarzinella. Then, through Kruskal-Wallis rank sum test (P<0.05), the genera with significant differences in abundance between two groups and two groups or more among the three groups were screened out. The results are shown in Figure 3 F (differential species test column chart of relative abundance at genus level in different buckwheat rhizospheres). Based on the characteristics of the highest abundance in KQ treatment, Flavisolibacter genus was selected for subsequent verification.

[0044] The pot experiment of the application shows that the soil microbial community has significant alleviating ability for the allelopathy of buckwheat: in unsterilized soil, the highest inhibition rate of tartary buckwheat on corn growth is significantly lower than that in sterilized soil. This shows that soil microorganisms may effectively weaken the allelopathy of buckwheat root exudates by metabolizing or degrading allelochemicals. Most studies show that some soil microorganisms have degradation effect on benzoic acid substances. For example, Acinetobacter suaedae screened from soil can degrade phenolic acids (p-hydroxybenzoic acid, coumaric acid) and alkane substances. Through LEfSe analysis and differential abundance screening, the application screens the genus Flavisolibacter which is significantly enriched in the rhizosphere of tartary buckwheat. The characteristics of the highest abundance in tartary buckwheat treatment show that it may adapt or depend on the environment of tartary buckwheat root exudates, and even have the ability to utilize specific exudates (such as target allelochemicals).

[0045] Example 6 Strain isolation and identification

[0046] Culturable bacteria were isolated from fresh rhizosphere soil samples by spread plate technique. Briefly, 10 g of buckwheat soil sample was added to a flask containing 90 mL of sterile water and glass beads, and shaken at 120 rpm for 30 min. The soil suspension was diluted to 10 -4 -6 and 10 μL aliquot of each dilution was spread on R2A solid medium (yeast extract powder 0.5 g; peptone 0.5 g; old protein amino acid 0.5 g; glucose 0.5 g; soluble starch 0.5 g; sodium pyruvate 0.3 g; potassium phosphate dibasic 0.3 g; magnesium sulfate 0.05 g; agar 15.0 g; distilled water 1.0 L; pH = 7.2). Plates were incubated at 30 °C for 3 d with five replicates for each dilution. Representative dominant bacterial colonies were selected for purification and stored on R2A agar slants at low temperature. Identification of purified bacteria was based on PCR amplification and 16S rRNA gene sequencing. PCR amplification (primers 27F: 5'-AGAGTTTGATCCTGGCTCAG-3' and 1492R: 5'-AAGGAGGTGATCCAGCCGCA-3'), the amplified products were detected by 1% agarose gel electrophoresis and then sent to Genescript Biotech Co., Ltd. for sequencing. The obtained sequences were compared in the GenBank database (http: / / blast.ncbi.nlm.nih.gov / ) to select reference strains with similarity of more than 95% as the standard, and the Neighbor-Joining method in MEGA v11 software was used to construct a phylogenetic tree, and the results are shown in Figure 1. Figure 4 G.

[0047] Strain FG1 has been deposited at China General Microbiological Culture Collection Center on July 24, 2025, and the deposit number is CGMCC No. 35360.

[0048] Example 7 Verification of strain degradation ability

[0049] To verify the degradation ability of FG1 to 2-(Formylamino)benzoic acid, a utilization test was carried out with this compound as the carbon source.

[0050] Carbon source utilization test: 2 mL of FG1 bacterial solution (hereinafter referred to as the test bacterial solution) with OD 600 = 0.5 was added to 50 mL of basic inorganic salt medium, 2-(Formylamino)benzoic acid was added as the carbon source, the concentration was 1 mg / mL, and the culture was shaken at 170 r / min, the temperature was 30 °C, and three replicates were set. Continuous culture for 7 d, sampling every 24 h, measuring absorbance. The results are shown in Figure 2. Figure 4 ​A (growth curve of strain using 2-(Formylamino)benzoic acid as carbon source) shows that the strain can use 2-(Formylamino)benzoic acid as carbon source.

[0051] Microbial degradation verification chromatographic conditions of FG1: chromatographic conditions Extended-18C chromatographic column (250 mm x 4.6 mm, 5 μm); mobile phase: methanol (A), 0.1% phosphoric acid aqueous solution (B); gradient elution program: 0-4.0 min: 30% A, 70% B; 4.0-8 min: 30%-40% A, 70%-60% B; 8-9 min: 30% A, 70% B; detection wavelength: 254 nm; flow rate: 0.8 mL / min; injection volume: 10 μL; column temperature: 25 °C. 2-(Formylamino)benzoic acid was weighed, dissolved with methanol (chromatographically pure) and diluted to 1 mg / mL stock solution, and then gradient diluted to 100 mg / L, 10 mg / L, 1 mg / L and 0.1 mg / L, and the content was determined by machine to draw a standard curve. 2 mL OD 600 = 0.5 of the test bacterial solution was added to 50 mL of the basic inorganic salt medium, 2-(Formylamino)benzoic acid was used as carbon source in the culture medium at a concentration of 1000 μg / L, and the culture medium without the addition of the bacterial solution was used as a control. The culture was shaken at 170 r / min at 28 °C. After 7 days, 5 mL of the culture solution was taken, 5 mL of methanol was added, mixed, and placed in a 4 °C refrigerator for 24 h, and then filtered with a 0.22 organic phase needle filter, and the content was detected by machine. Degradation rate (%) = (C C -C T ) / C C × 100 (Cc is the culture medium control without the addition of the FG1 strain; C T is the culture medium treatment with the addition of the FG1 strain). See Figure 4 B (degradation of 2-(Formylamino)benzoic acid by the strain), and the further carbon source degradation test results show that after 7 days of culture at an initial substrate concentration of 1000 μg / L, the concentration of 2-(Formylamino)benzoic acid in the FG1 treatment system is reduced to 150 μg / L, and the degradation rate is 85%.

[0052] To verify the strain's alleviating effect on allelochemicals in plant systems, a petri dish promoting growth test was performed. FG1 strain petri dish degradation test: four treatments were set: exogenous addition of FG1 (OD 600 = 0.5, about 3 x 10 7CFU / mL) and 10 mL of 100 μM 2-(Formylamino)benzoic acid (T1) was added simultaneously; FG1 (about 6 x 10 6 CFU / mL) and 10 mL of 100 μM 2-(Formylamino)benzoic acid (T2) was added simultaneously; only 10 mL of 100 μM 2-(Formylamino)benzoic acid (M) was added; and only 10 mL of sterile water (C) was added. Each treatment was set up in 15 replicates, and 10 mL of each concentration of the allelochemical solution and the corresponding amount of bacterial suspension (OD 600 = 0.5) was added, and 10 mL of sterile water was added to the CK. The Petri dishes were placed in a culture room (temperature 25°C, 16 h light / 8 h dark, light intensity 8000 Lux, relative humidity 60%) for incubation. The corresponding solution was replaced as needed to maintain the humidity and concentration of the filter paper in the Petri dishes during the incubation period. After 7 days of germination, the lengths of the seed radicle and plumule were measured.

[0053] See Figure 4 C, Figure 4 D, and Figure 4 E, the results showed that the exogenous addition of FG1 strain (OD 600 = 0.5, about 3 x 10 7 CFU / mL) and 10 mL of 100 μM 2-(Formylamino)benzoic acid (T1) was added simultaneously; FG1 (about 6 x 10 Figure 4 C) and the plumule length ( ​ D) were significantly higher than the treatment group in which only 10 mL of 100 μM 2-(Formylamino)benzoic acid (M) was added, but significantly lower than the sterile water control group (C) (P < 0.05), indicating that FG1 can effectively alleviate the inhibitory effect of the allelochemical on the growth of corn.

Claims

1. A ginseng-derived yellowish-brown soil-derived fungus, characterized by: The microbiological classification of the ginseng yellow soil-derived fungus is Flavisoliacterginsengisoli. The ginseng yellow soil-derived fungus was deposited at the China General Microbiological Culture Collection Center on July 24, 2025, with the accession number CGMCC No. 35360.

2. The application of the ginseng yellow soil-derived fungus as described in claim 1 in alleviating or reducing allelopathic effects caused by plant cultivation.

3. The application of the ginseng yellow soil-derived fungus as described in claim 1 in alleviating or reducing allelopathic effects caused by buckwheat cultivation.

4. The application of the ginseng yellow soil-derived fungus as described in claim 1 in alleviating or reducing allelopathic effects caused by continuous or rotational planting of buckwheat.

5. The application of the ginseng yellow soil-derived bacteria as described in claim 1 in degrading allelochemicals produced by continuous or rotational planting of buckwheat.

6. The application according to claim 5, characterized in that: The allelochemical is benzoic acid.

7. The application according to claim 6, characterized in that: The allelochemical is 2-(formamide)benzoic acid.

8. An auxiliary additive for buckwheat cultivation obtained based on the application described in any one of claims 2-7.

9. An auxiliary additive for buckwheat cultivation, characterized in that: The auxiliary additives include the ginseng yellow soil-derived bacteria as described in claim 1 and an agriculturally acceptable carrier.

10. The auxiliary additive for buckwheat cultivation according to claim 9, characterized in that: The auxiliary additive is a bacterial liquid, bacterial suspension, fermentation product, bacterial fertilizer, and / or liquid fertilizer; the effective live bacteria of ginseng yellow soil-derived bacteria in the auxiliary additive is not less than 6 × 10⁻⁶. 6 CFU / mL.

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