A banana root exudate 10-hydroxydecanoic acid, its preparation method and application

Abstract

The present invention provides the use of banana root exudates or ethanol extracts of banana root exudates in the preparation of 10-hydroxydecanoic acid. By inducing changes in banana root exudates with a newly isolated Streptomyces sp., the key root exudate 10-hydroxydecanoic acid can be isolated, which can effectively antagonize Gibberella zeae and others, but has no inhibitory effect on Fusarium oxysporum f. sp. cubense race 4 and others. However, 10-hydroxydecanoic acid can effectively inhibit Fusarium oxysporum f. sp. cubense race 4 in the rhizosphere soil of banana and effectively control banana wilt caused by Fusarium oxysporum f. sp. cubense race 4, and increase the Sphingomonas abundance of genera Bacills of bacteria Pseudolabrys and others in the rhizosphere soil of banana. The present invention provides new methods and ideas for the prevention and control of wilt diseases and the control of Gibberella zeae, Colletotrichum gloeosporioides, Colletotrichum musae, Colletotrichum litchii, Colletotrichum gloeosporioides, Botrytis cinerea and others.

Description

Technical Field

[0001] The present invention relates to a banana root exudate, and in particular to a banana root exudate 10-hydroxydecanoic acid and its preparation method and application. Background Art

[0002] Banana ( Musa spp.) is a plant of the genus Musa in the family Musaceae, the most important fruit and grain crop in the world, the second largest fruit and the fourth largest food crop globally (Zhang et al., 2023). Banana wilt seriously threatens the banana industry. There are neither resistant strains nor effective chemical agents, and the banana industry once faced the situation of extinction and crop failure. To solve the industrial problems, over a period of 20 years, the National Banana Industry Technology System has basically achieved the prevention and control of banana wilt through a series of measures. To achieve long-term and effective field control of banana wilt, cultivating resistant (tolerant) strains and screening antagonistic biocontrol bacteria are two important measures.

[0003] Banana wilt is a devastating soil-borne disease caused by the pathogen Fusarium oxysporum f. sp. Fusarium oxysporum f. sp. Cubense , Foc TR4. Its prevention and control is a worldwide problem. When the disease occurs severely, it will lead to a sharp reduction in the banana planting area. Breeding disease-resistant varieties is the most effective and fundamental control approach. However, currently, most edible cultivated bananas are triploid sterile and parthenocarpic, which restricts the effective recombination and exchange of genetic materials in the process of evolution, resulting in a relatively simple genetic background and making it difficult to improve through sexual hybridization. Therefore, the progress of cultivating resistant strains is relatively slow.

[0004] Microecological control based on antagonistic microorganisms is one of the green and effective control measures for banana wilt and has become a current research hotspot. The project team has long been engaged in the research on banana root exudates and has solved bottleneck problems such as single control measures and poor control effects for banana wilt through the interaction between root exudates and rhizosphere microbial communities. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a banana root exudate 10-hydroxydecanoic acid and its preparation method and application.

[0006] The first aspect of the present invention is to provide the application of Streptomyces Streptomyces Yongxingensis sp. nov., or banana root exudates or methanol extracts of banana root exudates in the preparation of 10-hydroxydecanoic acid.

[0007] The banana root exudates described in the context of the present invention are as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and the fourth physiological race of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water and culturing is continued for 2 - 4 days. The liquid corresponding to the sterile water is collected, which is the banana root exudates.

[0008] The second aspect of the present invention is to provide a method for preparing 10 - hydroxydecanoic acid, which is isolated from banana root exudates.

[0009] Preferably, the specific steps of the preparation method are as follows: (1) Concentrate the banana root exudates to an extract; (2) Dissolve the extract with methanol and then elute it through Diaion HP20 macroporous adsorption resin with a gradient of MeOH / H2O (1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, MeOH). After detection and comparison with the 10 - hydroxydecanoic acid standard, the effective component Fr.A9 containing 10 - hydroxydecanoic acid is obtained; (3) The effective component Fr.A9 passes through an ODS reversed - phase silica gel column and is eluted with MeOH / H2O (5:5, 6:4, 7:3, 8:2, 9:1, MeOH) as the mobile phase. After combination of detection and comparison with the 10 - hydroxydecanoic acid standard, the effective component Fr.B6 containing 10 - hydroxydecanoic acid is obtained; (4) The effective component Fr.B6 passes through Sephadex LH - 20 gel column chromatography and is eluted with CH2Cl2 / MeOH (2:1) as the eluent. After combination of detection and comparison with the 10 - hydroxydecanoic acid standard, the effective component Fr.C5 containing 10 - hydroxydecanoic acid is obtained; (5) Fr.C5 passes through an ODS - C18 reversed - phase silica gel column and is eluted with MeOH / H2O (80:20) as the mobile phase. After combination of detection and comparison with the 10 - hydroxydecanoic acid standard, the effective component Fr.D4 - 3 containing 10 - hydroxydecanoic acid is obtained; (6) The component Fr.D4 - 3 is repeatedly separated and purified by RP - HPLC (RID A: Refractive Index Signal; λ = 230) to obtain the high - purity monomeric compound H5, thus obtaining the product.

[0010] The third aspect of the present invention is to provide 10 - hydroxydecanoic acid prepared by the preparation method described in the second aspect of the present invention.

[0011] The fourth aspect of the present invention is to provide Streptomyces Streptomyces YongxingensisThe use of Streptomyces Yongxingensis sp. nov., or banana root exudates, or methanol extracts of banana root exudates, or 10-hydroxydecanoic acid in the preparation of a preparation for antagonizing Gibberella zeae, and / or Colletotrichum acutatum, and / or Colletotrichum musae, and / or Colletotrichum litchii, and / or Colletotrichum gloeosporioides, and / or Botrytis cinerea.

[0012] The fifth aspect of the present invention is to provide the use of Streptomyces Yongxingensis sp. nov., or banana root exudates, or methanol extracts of banana root exudates, or 10-hydroxydecanoic acid in the preparation of a preparation for antagonizing Gibberella zeae, and / or Colletotrichum acutatum, and / or Colletotrichum musae, and / or Colletotrichum litchii, and / or Colletotrichum gloeosporioides, and / or Botrytis cinerea but not antagonizing Fusarium oxysporum f. sp. cubense race 1 and / or Fusarium oxysporum f. sp. cubense race 4.

[0013] The sixth aspect of the present invention is to provide the use of Streptomyces Yongxingensis sp. nov., or banana root exudates, or methanol extracts of banana root exudates, or 10-hydroxydecanoic acid in the preparation of a preparation for controlling diseases caused by Gibberella zeae, and / or Colletotrichum acutatum, and / or Colletotrichum musae, and / or Colletotrichum litchii, and / or Colletotrichum gloeosporioides, and / or Botrytis cinerea.

[0014] The seventh aspect of the present invention is to provide Streptomyces Streptomyces Yongxingensis sp. nov., or banana root exudates, or methanol extracts of banana root exudates, or 10-hydroxydecanoic acid in the preparation of a preparation for inhibiting Fusarium oxysporum f. sp. cubense race 4 in banana rhizosphere soil.

[0015] The eighth aspect of the present invention is to provide Streptomyces Streptomyces Yongxingensis sp. nov., or banana root exudates, or methanol extracts of banana root exudates, or 10-hydroxydecanoic acid in the preparation of a preparation for controlling banana wilt caused by Fusarium oxysporum f. sp. cubense race 4.

[0016] The ninth aspect of the present invention is to provide Streptomyces Streptomyces Yongxingensis sp. nov., or banana root exudates, or methanol extracts of banana root exudates, or 10-hydroxydecanoic acid in the preparation of a preparation for increasing the abundance of Sphingomonas genus, and / or Bacills genus, and / or Pseudolabrys genus in banana rhizosphere soil.

[0017] Advantages of the present invention:

[0018] The present invention induces changes in banana root exudates through the new species Streptomyces Yongxingensis sp. nov., and the key root exudate 10-hydroxydecanoic acid can be isolated. 10-hydroxydecanoic acid can effectively antagonize Gibberella zeae, Colletotrichum gloeosporioides, Colletotrichum musae, Colletotrichum litchii, Colletotrichum gloeosporioides, Botrytis cinerea, etc., but has no inhibitory effect on Fusarium oxysporum f. sp. cubense race 1 and Fusarium oxysporum f. sp. cubense race 4. However, 10-hydroxydecanoic acid can effectively inhibit Fusarium oxysporum f. sp. cubense race 4 in banana rhizosphere soil and effectively control banana wilt caused by Fusarium oxysporum f. sp. cubense race 4, and improve the abundance of genera, genera, genera, etc. in banana rhizosphere soil. The present invention provides a new method and idea for the prevention and control of wilt disease, and also provides a new method and idea for the prevention and control of Gibberella zeae, Colletotrichum gloeosporioides, Colletotrichum musae, Colletotrichum litchii, Colletotrichum gloeosporioides, Botrytis cinerea, etc. Sphingomonas Genus, Bacills Genus, Pseudolabrys Genus, etc. in banana rhizosphere soil. The present invention provides a new method and idea for the prevention and control of wilt disease, and also provides a new method and idea for the prevention and control of Gibberella zeae, Colletotrichum gloeosporioides, Colletotrichum musae, Colletotrichum litchii, Colletotrichum gloeosporioides, Botrytis cinerea, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the flow chart for the collection of banana root exudates.

[0020] Figure 2 is for the excavation of key root exudates.

[0021] Figure 3 is the structure of the compound 10-hydroxydecanoic acid.

[0022] Figure 4 is the hydrogen spectrum of the compound 10-hydroxydecanoic acid.

[0023] Figure 5 is the carbon spectrum of the compound 10-hydroxydecanoic acid.

[0024] Figure 6 is the result of the inhibitory effect of 10-hydroxydecanoic acid on plant pathogens.

[0025] Figure 7 is the control effect of 10-hydroxydecanoic acid on banana wilt in banana potted seedlings.

[0026] Figure 8 is for 10-hydroxydecanoic acid in banana rhizosphere soil Foc Effect of the colonization of TR4.

[0027] Figure 9 is the effect of 10-hydroxydecanoic acid on the banana rhizosphere microbiome. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be further described below with reference to the accompanying drawings and in conjunction with specific embodiments to better understand the present invention. Where specific techniques or conditions are not specified in the examples, the methods are based on those described in the literature in this field or on the product specifications. Where the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional products.

[0029] 1 Test materials

[0030] 1.1 Test pathogens

[0031] Fusarium wilt race 4 Fusarium oxysporum f. sp. Cubense tropicalRace 4 ( Foc TR4, ATCC 76255), banana wilt pathogen race 1 F. oxysporum f. sp. cubense Race 1 (ACCC 31271) ( Foc 1); wheat fusarium head blight pathogen Fusarium graminearum Schwabe (ATCC MYA-4620); Colletotrichum spp. Colletotrichum fragariae Brooks (ATCC58718); banana anthracnose pathogen Colletotrichum musae (ACCC 96167), Colletotrichum gloeosporioides (Penz) Saec (ATCC MYA-456), Colletotrichum gloeosporioides (Penz) Saec (ATCC MYA-456), Colletotrichum gloeosporioides (Penz) Saec (ATCC MYA-456) Colletotrichum musae (ATCC 96167); Botrytis cinerea Botrytis cinerea Persoon (ATCC11542). The above pathogens were all strains preserved in our laboratory.

[0032] 1.2 Main Reagents

[0033] The main reagents used in this experiment are shown in Table 1.

[0034] Table 1 Main reagents and sources

[0035] Name of reagent Source Bacterial genomic DNA rapid extraction kit Beijing Bioteke Corporation 2×Es Taq Master Mix (Dye) Bomed Biotech Co., Ltd. DNA marker (Maker D2000) Beijing ComWin Biotech Co., Ltd. Nucleic acid stain GoldView [[ID= ​ ​ ​ ​ ​ ​ ​

[0036] 1.3 Test instruments and equipment

[0037] The main instruments and equipment required for this experiment are shown in Table 2.

[0038] Table 2 Instruments and equipment

[0039] ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Carl Zeiss AG, Germany

[0040] 1.4 Main culture medium

[0041] The main test media used in this study are shown in Table 3.

[0042] Table 3 Main media and formulations

[0043] Name of culture medium Culture medium formula Potato Dextrose Agar (PDB) Potato 200.0 g, dextrose 20.0 g, water 1000 mL. LB medium Yeast extract 5 g, tryptone 10 g, NaCl 10 g, agar 20 g, water 1000 mL, pH 7.2 - 7.5

[0044] 1.5 Test banana seedlings

[0045] All the banana tissue culture seedlings are healthy Brazilian banana cup seedlings at the 5-6 leaf stage with relatively consistent growth, provided by the Danzhou Tissue Culture Center of Chinese Academy of Tropical Agricultural Sciences.

[0046] 1.6 Test soil

[0047] The soil used in the experiment was taken from a banana orchard in Danzhou City, Hainan Province (109°54'66"E, 19°44′63"N), and the soil type is red soil.

[0048] 2 Experimental methods and results

[0049] 2.1 Experimental design, collection of root exudates and metabolomics (LC-MS) analysis

[0050] Previous studies found that Streptomyces Streptomyces Yongxingensis sp. nov. (deposited in the China Center for Type Culture Collection (CCTCC) on March 30, 2021, with the deposit number CCTCC NO: M 2021303, and its characteristics refer to Chinese Patent CN202111205925.6) can induce changes in banana root exudates and produce new substances against banana wilt. Therefore, in this study, a hydroponic split-root system was used to collect banana root exudates ( Figure 1 ) under controlled conditions. The split-root system consists of two independent culture chambers on the left and right. The left chamber is inoculated with microorganisms (the spore suspension of the strain can be directly added to the culture solution), and the right chamber is used for collecting root exudates. The roots of a single seedling are divided into two parts and placed in the left and right chambers respectively. Initially, Hoagland's nutrient solution is used for both chambers. After inoculating microorganisms in the left chamber ( Foc the inoculation concentration of TR4 is 1.0×10 5 cfu / mL, and the inoculation concentration of Streptomyces Sy is 1.0×10 7 cfu / mL), it is cultured at 28°C with a 16 / 8 day-night ratio for 48 h; the nutrient solution in the right chamber is replaced with sterile water, and it is continuously cultured for 72 h, and the liquid in the right chamber is collected as root exudates, which are freeze-dried and then subjected to metabolomics (LC-MS) determination and analysis. The experiment has a total of 2 treatments: inoculation Foc TR4 blank control and simultaneous inoculation of Foc TR4 + Streptomyces Streptomyces Yongxingensissp. nov. treatment group. Each treatment was set with 6 biological replicates, and 10 banana seedlings were taken from each replicate to collect root exudates.

[0051] Select the liquid chromatography-mass spectrometry system (LC-MS) composed of Waters UPLC Acquity I-Class PLUS ultra-high performance liquid chromatography tandem with Waters UPLC Xevo G2-XS QTOF high-resolution mass spectrometry as the instrument platform for metabolomics analysis. Mass spectrometry data collection was carried out under the control of the acquisition software (MassLynx V4.2, Waters); the collected raw data was imported into the processing software Progenesis QI for processing such as baseline filtering, peak identification, integration, retention time correction, and peak alignment, and finally a data matrix of retention time, mass-to-charge ratio, and peak intensity was obtained; then the software was used for library search and identification of characteristic peaks, the mass spectrometry information was matched with the metabolic database, the mass spectrometry mass error was set to less than 10 ppm, and at the same time the metabolites were identified according to the secondary mass spectrometry matching score, and the relative concentration of each metabolite was calculated by internal standard normalization method; all the data after qualitative analysis was imported into SIMCA 14.1 software for Pareto-scaling normalization, and combined with univariate statistical analysis (Student’s t-test, P<0.01) and fold change (FC > 2) to screen for differential metabolites or root exudates.

[0052] Adopt Figure 1 The flowchart method was used to collect root exudates and perform metabolome sequencing. A total of 542 root exudates were identified, and a comparative analysis was performed on the differential metabolites generated between the two treatments. 198 differential metabolites were screened, of which 98 were down-regulated and 100 were up-regulated in the treatment ( Figure 2 a in). To further screen for key secreted metabolites, we filtered out metabolites with low abundance (peak<1e-5), and combined with the parameters (|log2FC|≥2 & VIP≥1 & p-value≤0.05) to identify 20 candidate metabolites in total ( Figure 2 b in). Based on the content and functional analysis of key metabolites, a candidate key root exudate, 10-hydroxycapric acid, was located. 10-hydroxycapric acid is a white powder with the molecular formula C 10 H 20 O3, and its planar structure is as shown in Figure 3 . The standard product of 10-hydroxycapric acid (purity≥99.9%) was purchased through Dingxiangtong for subsequent experiments.

[0053] 2.2 Isolation and purification of the key root exudate 10-hydroxycapric acid

[0054] Collect the root exudates of the right ventricle based on the method of 2.1, obtain 60 L of the root exudate solution, and concentrate it under reduced pressure to an extract at 45 °C. Dissolve the extract with methanol, pass it through Diaion HP20 macroporous adsorption resin, and elute it with a gradient of MeOH / H2O (1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, MeOH) to obtain 10 fractions (Fr.A1 ~ Fr.A10). After TLC detection and comparison with the TLC of the 10-hydroxydecanoic acid standard, the effective fraction Fr.A9 (6.3221 g) containing 10-hydroxydecanoic acid was obtained. The effective fraction Fr.A9 was passed through an ODS reverse silica gel column and eluted with MeOH / H2O (5:5, 6:4, 7:3, 8:2, 9:1, MeOH) as the mobile phase. 65 fractions were collected, and the fractions in which 10-hydroxydecanoic acid was present were detected by TLC to combine the fractions to obtain 1.8657 g of the effective fraction Fr.B6. Fr.B6 was subjected to Sephadex LH-20 gel column chromatography and eluted with CH2Cl2 / MeOH (2:1) as the eluent. A total of 42 fractions were collected, and the fractions containing 10-hydroxydecanoic acid were determined by TLC and HPLC to combine and obtain the effective fraction Fr.C5 (1.1343 g). Fr.C5 was passed through an ODS-C18 reverse silica gel column and eluted with MeOH / H2O (80:20) as the mobile phase. The fractions containing 10-hydroxydecanoic acid were determined by TLC and HPLC and combined to obtain the effective fraction Fr.D4-3 (0.5108), and then subjected to RP-HPLC purification in the later stage.

[0055] The fraction Fr.D4-3 was repeatedly separated and purified by RP-HPLC (RID A: Refractive Index Signal; λ = 230) to obtain the high-purity monomer compound H5 (63.85 mg, MeOH:H2O = 80:20, 2 mL / min, tR = 36 min). After dissolving it with CD2OD, it was sent for NMR spectrum scanning and structure identification on a 600M NMR.

[0056] Compound H5 is a white powder with the molecular formula C 10 H 20 O3. According to the NMR spectrum of the compound ( Figures 4 - 5 ), and by comparing with the literature, it was found that the spectral data of compound H5 were consistent with those reported in the literature, and compound H5 was determined to be 10-hydroxycapric acid. The planar structure of the compound was analyzed by 2D-NMR spectra, as shown in Figure 3 Figure.

[0057] 2.3 Broad-spectrum antifungal activity of 10-hydroxydecanoic acid

[0058] To evaluate the broad-spectrum antifungal activity of 10-hydroxydecanoic acid, the growth rate method was used to determine the broad-spectrum antifungal activity against 8 plant pathogenic fungi. 10-Hydroxydecanoic acid dissolved in DMSO (20.0 mg / ml) was added to the PDA medium at 45 - 50 °C to prepare PDA plates with a final concentration of 10 mg / m, with an equal amount of DMSO added as a control. Foc TR4, Foc TR1, Gibberella zeae, Colletotrichum gloeosporioides of strawberry, Colletotrichum musae of banana, Colletotrichum siamense of litchi, Colletotrichum gloeosporioides of mango, and Botrytis cinerea of grape fungal discs (Φ = 5 mm) were respectively inoculated into the center of different plates and cultured at 28 ± 2 °C until the control mycelium reached the edge of the plate. The average value of the vertical diameter of each colony was measured. Each treatment was repeated 3 times. The calculation formula for the mycelial growth inhibition rate is as follows (Nimaichand et al., 2015):

[0059]

[0060] Where: C is the average diameter of the colonies in the control group, and T is the average diameter of the colonies in the treatment group.

[0061] The results are as Figure 6 shown. There were significant differences in the inhibitory effects of 10-hydroxydecanoic acid on different pathogenic fungi. Among them, the inhibition rate against Colletotrichum siamense of litchi was 53.94 ± 0.72%, significantly higher than the other 7 pathogenic fungi. However, it had no antibacterial activity against Race 1 and Race 4 of Fusarium oxysporum f. sp. cubense; the inhibitory activity against Colletotrichum gloeosporioides of mango was also low, with an inhibition rate of 44.48 ± 0.68%, and there were no significant differences in the antibacterial effects compared with other several pathogenic fungi such as Gibberella zeae, Colletotrichum gloeosporioides of strawberry, Colletotrichum musae of banana, Colletotrichum siamense of litchi, and Botrytis cinerea of grape. These results indicate that 10-hydroxydecanoic acid has an antagonistic effect on plant pathogenic fungi such as Gibberella zeae, Colletotrichum gloeosporioides of strawberry, Colletotrichum musae of banana, Colletotrichum siamense of litchi, Colletotrichum gloeosporioides of mango, and Botrytis cinerea of grape, but has no antibacterial effect on Fusarium oxysporum f. sp. cubense.

[0062] 2.4 Control effect of root exudate 10-hydroxydecanoic acid on Fusarium oxysporum f. sp. cubense

[0063] 2.4.1 Pot experiment

[0064] The pot experiment was carried out at the Sanya Institute of Chinese Academy of Tropical Agricultural Sciences from April to June 2024. The greenhouse conditions were 28 °C, humidity 70%, and natural light. Healthy soil from a banana orchard in Danzhou City, Hainan Province was collected and sieved through a 20-mesh sieve. Banana seedlings with consistent growth and 3 - 4 leaves were selected, rinsed clean with sterile water, and planted in plastic pots containing 1000 g of soil, with 30 plants in each treatment. The experiment had 3 treatment groups: Control (not inoculated FocTR4, treated with sterile water); Treatment (inoculation Foc TR4, application Streptomyces Yongxingensis sp. nov. 2-11 inoculum, preservation number CCTCC NO: M 2021303, positive control); 10-hydroxycapric acid (inoculation Foc TR4, applied with 1 mM 10-hydroxydecanoic acid). Each treatment had three replicates.

[0065] 2.4.2 Disease index statistics

[0066] According to the description of Himaman et al., (2016), a total of 30 banana seedlings were selected from each group, and the disease index (DI) of the inoculated plants for 49 days was evaluated. It was divided into 5 grades, calculated based on the proportion of yellowing disease leaves in one plant. Grade 0: healthy plants; Grade 1: 1-25% yellowing disease leaves; Grade 2: 26-50% yellowing disease leaves; Grade 3: 51-75% yellowing disease leaves; Grade 4: more than 75% yellowing disease leaves. The formula for calculating the disease index (DI) of banana wilt is as follows:

[0067]

[0068] The control effect of 10-hydroxydecanoic acid on banana wilt in potted banana plants is as Figure 7 shown. The incidence rate of the control group after 49 days was 78.33%, the disease was severe, and the plant seedlings were significantly wilted; while after treating banana seedlings with strain 2-11 inoculum and 10-hydroxydecanoic acid, the disease symptoms were significantly inhibited, and the seedlings were healthy without disease ( Figure 7 in a). Compared with the control group (contrlo), after 49 days of treatment with strain 2-11 inoculum (Treatment) and 10-hydroxydecanoic acid (10-hydroxydecanoic acid), the disease index decreased to 19.16% and 19.88% respectively, and there was no significant difference between the two ( Figure 7 in b). It shows that 10-hydroxydecanoic acid has a good control effect on banana wilt and can inhibit the infection of banana wilt pathogen.

[0069] 2.4.3 Quantitative detection of Foc TR4 in soil

[0070] Take the rhizosphere soil samples of the potted plants after 49 days for quantitative detection of banana wilt pathogen. On the plate containing the modified Komada selective medium, the serial dilution method of the rhizosphere soil suspension was used to determine the banana wilt pathogen in the banana rhizosphere ( FocTR4) Colony - forming unit number (cfu / g). Colony - forming unit number (cfu / g) = Average number of colonies per petri dish × Dilution factor × 5 / Soil weight.

[0071] The results showed that for the rhizosphere soil of bananas under different treatments Foc The colonization of TR4 was as Figure 8 shown. The results showed that in the Control group Foc the number of TR4 pathogenic bacteria was the highest, reaching 5.58×10 4 CFU / g. After treatment with the bacterial agent of strain 2 - 11 and 10 - hydroxydecanoic acid, the number of pathogenic bacteria in the rhizosphere of bananas decreased significantly, being 1150 CFU / g and 950 CFU / g respectively. The results showed that 10 - hydroxydecanoic acid could inhibit Foc the colonization of TR4 in the rhizosphere of bananas and had a good control effect on banana wilt disease.

[0072] 2.5 Effect of root exudate 10 - hydroxydecanoic acid on the banana rhizosphere microbiome

[0073] 2.5.1 Soil DNA extraction and PCR amplification

[0074] According to the method in the E.Z.N.A. ® Soil DNA Kit Protocol (Omega Bio - tek, Norcross, GA, U.S.), total soil microbial DNA was extracted. The concentration of total DNA was detected using a NanoDrop 2000 UV - vis spectrophotometer (Thermo Scientific, Wilmington, USA). The integrity of DNA was detected by 1% agarose gel electrophoresis. Using the extracted total soil DNA as a template, with a thermal cycling PCR system (GeneAmp 9700, ABI, USA), the V3 - V4 region of the bacterial 16S rRNA gene was amplified using the bacterial universal primers 338F (5'-ACTCCTACGGGAGGCAGCAG - 3') / 806R (5'-GGACTACHVGGGTWTCTAAT - 3'). The polymerase chain reaction of bacterial 16S rRNA was carried out using the following procedure: pre - denaturation at 95℃ for 3 min, denaturation at 95℃ for 30 s, annealing at 55℃ for 30 s, extension at 72℃ for 45 s, for 27 cycles, and finally extension at 72℃ for 10 min.

[0075] 2.5.2 High - throughput (Illumina MiSeq) sequencing

[0076] According to the standard method of Majorbio Bio Pharm Technology Co., Ltd. (Shanghai, China), purified DNA fragments were pooled in equimolar amounts and paired-end sequencing (2×300) was performed using the Illumina MiSeq platform (Illumina, San Diego, USA).

[0077] 2.5.3 Sequence processing and bioinformatics analysis

[0078] The original fastq files were demultiplexed, the quality was filtered by Trimmomatic, and merged by FLASH with the following criteria: (i) reads were truncated at any position where the average quality score was <20 over a 50-bp sliding window; (ii) primer perfect matches were allowed with 2-nucleotide mismatches, and reads containing ambiguous bases were removed; and (iii) sequences with an overlap length greater than 10 bp were merged based on the overlapping sequences. Operational taxonomic units (OTUs) were clustered with 97% similarity using UPARSE (version 7.1, http: / / drive5.com / UPARSE / ), and chimeric sequences were identified and removed using UCHIME. Taxonomic analysis was performed on each 16S rRNA gene sequence and sequences against the Silva (SSU123) 16S rRNA database, and fungal ITS sequences were analyzed using the RDP classifier algorithm (http: / / RDP.cme.msu.edu / ) with a confidence threshold of 70%.

[0079] To study the effects of 10-hydroxydecanoic acid on the banana rhizosphere microbiome, high-throughput sequencing of banana rhizosphere soil was performed. The results showed that microbiome analysis found no significant differences in the α-diversity indices between the 10-hydroxydecanoic acid and strain 2-11 inoculant treatments, but they were significantly different from the control group ( Figure 9 in a). Similarly for β-diversity, the 10-hydroxydecanoic acid and strain 2-11 inoculant treatment groups were on the right side of PCoA1 (48.01%), while the control group was on the left side ( β in b), which implies that the 10-hydroxydecanoic acid and strain 2-11 inoculant treatments had more similar microbial compositions. Figure 9 Genus (Sphingomonas), Sphingomonas Genus (Bacillus), and Bacills Genus (Pseudomonas) were significantly higher in the 10-hydroxydecanoic acid and strain 2-11 inoculant groups than in the control group ( Pseudolabrys in c). This also indicates that 10-hydroxydecanoic acid can trigger the directional assembly of microorganisms, and the assembly direction is similar to that of the strain 2-11 inoculant treatment. By comparison, it was found that the genus Bacillus had a higher abundance in the 10-hydroxydecanoic acid treatment group and was also the genus with the largest difference in the change multiple ( Figure 9 in d). Figure 9in d-e).

[0080] The specific embodiments of the present invention have been described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the invention are also within the scope of the present invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

Claims

1. Use of banana root exudates, or methanol extracts of banana root exudates, in the preparation of 10-hydroxydecanoic acid, wherein, The banana root exudates are as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and the fourth physiological race of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water and culturing is continued for 2 - 4 days. The liquid corresponding to the sterile water is collected as the banana root exudates; The preparation method of the methanol extract is as follows: The banana root exudates are concentrated to an extract and dissolved with methanol; The preservation number of Streptomyces Yongxingensis sp. nov. is CCTCC NO: M 2021303.

2. A method for preparing 10-hydroxydecanoic acid, characterized in that, Isolated from the banana root exudates, and the banana root exudates are as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and the fourth physiological race of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water and culturing is continued for 2 - ​ ​ ​ ​ ​ ​ The Streptomyces Yongxingensis sp. nov. has a preservation number of CCTCC NO: M2021303.

3. Use of 10-hydroxydecanoic acid prepared from banana root exudates or methanol extracts of banana root exudates in the preparation of a preparation for antagonizing Gibberella zeae, and / or Colletotrichum acutatum, and / or Colletotrichum musae, and / or Colletotrichum gloeosporioides, and / or Colletotrichum mangiferae, and / or Botrytis cinerea; wherein, The banana root exudates are obtained as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and Race 4 of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water and culturing is continued for 2 - 4 days. The liquid corresponding to the sterile water is collected as the banana root exudates. The preparation method of the methanol extract is as follows: The banana root exudates are concentrated to an extract and dissolved in methanol. The Streptomyces Yongxingensis sp. nov. has a preservation number of CCTCC NO: M2021303.

4. Use of 10-hydroxydecanoic acid prepared from banana root exudates or methanol extracts of banana root exudates in the preparation of a preparation that antagonizes Fusarium graminearum, and / or Colletotrichum acutatum, and / or Colletotrichum musae, and / or Colletotrichum gloeosporioides, and / or Colletotrichum mangiferae, and / or Botrytis cinerea but does not antagonize Race 1 and / or Race 4 of Fusarium oxysporum f. sp. cubense; wherein, The banana root exudates are obtained as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and Race 4 of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water and culturing is continued for 2 - 4 days. The liquid corresponding to the sterile water is collected as the banana root exudates. The preparation method of the methanol extract is as follows: The banana root exudates are concentrated to an extract and dissolved in methanol. The Streptomyces Yongxingensis sp. nov. has a preservation number of CCTCC NO: M2021303.

5. Use of 10-hydroxydecanoic acid prepared from banana root exudates or methanol extracts of banana root exudates in the preparation of a preparation for preventing and treating diseases caused by Gibberella zeae, and / or Colletotrichum acutatum, and / or Colletotrichum musae, and / or Colletotrichum gloeosporioides, and / or Colletotrichum gloeosporioides, and / or Botrytis cinerea; wherein, The banana root exudates are obtained as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and Race 4 of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water and culturing is continued for 2 - 4 days. The liquid corresponding to the sterile water is collected as the banana root exudates. The preparation method of the methanol extract is as follows: The banana root exudates are concentrated to an extract and dissolved in methanol. The Streptomyces Yongxingensis sp. nov. has a preservation number of CCTCC NO: M2021303.

6. Use of 10-hydroxydecanoic acid prepared from banana root exudates or methanol extracts of banana root exudates in the preparation of a preparation for inhibiting Race 4 of Fusarium oxysporum f. sp. cubense in banana rhizosphere soil; wherein, The banana root exudates are obtained as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and the fourth physiological race of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water, and culturing is continued for 2 - 4 days. The liquid corresponding to the sterile water is collected as the banana root exudates; The preparation method of the methanol extract is as follows: The banana root exudates are concentrated to an extract and dissolved with methanol; The preservation number of Streptomyces Yongxingensis sp. nov. is CCTCC NO: M 2021303.

7. Use of 10-hydroxydecanoic acid prepared from banana root exudates or methanol extracts of banana root exudates in the preparation of a preparation for controlling banana wilt caused by Race 4 of Fusarium oxysporum f. sp. cubense; wherein, The banana root exudates are obtained as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and the fourth physiological race of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water, and culturing is continued for 2 - 4 days. The liquid corresponding to the sterile water is collected as the banana root exudates; The preparation method of the methanol extract is as follows: The banana root exudates are concentrated to an extract and dissolved with methanol; The preservation number of Streptomyces Yongxingensis sp. nov. is CCTCC NO: M 2021303.

8. Use of 10-hydroxydecanoic acid prepared from banana root exudates or methanol extracts of banana root exudates in the preparation of a preparation for increasing the abundance of the genus Sphingomonas bacteria, and / or Bacills bacteria, and / or Pseudolabrys bacteria in banana rhizosphere soil; wherein, The banana root exudates are obtained as follows: Part of the roots of the same banana plant are placed in a nutrient solution inoculated with Streptomyces Yongxingensis sp. nov. and the fourth physiological race of Fusarium oxysporum f. sp. cubense, and part of the roots are placed in a sterile nutrient solution. After culturing for 1 - 3 days, the sterile nutrient solution is replaced with sterile water, and culturing is continued for 2 - 4 days. The liquid corresponding to the sterile water is collected as the banana root exudates; The preparation method of the methanol extract is as follows: The banana root exudates are concentrated to an extract and dissolved with methanol; The preservation number of Streptomyces Yongxingensis sp. nov. is CCTCC NO: M 2021303.

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