Construction method of rhizosphere soil microbial synthetic community for improving fruit quality of residual dried chilies

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to a construction method of a rhizosphere soil microorganism synthetic community for improving the quality of residual dry chili fruits. The method comprises the following steps: selecting peppers with different remaining stems in different regions, and detecting the fruit eating quality to obtain eating quality indexes; then selecting regional pepper rhizosphere soil with good quality, separating and screening microorganisms, and identifying species information of the microorganisms; performing correlation analysis on microorganisms and edible quality indexes to obtain correlation information between microbial strains and edible quality, screening out strains having a promoting effect on the quality of the remaining dry red peppers, and synthesizing a microbial community. Starting from microbial resource development of pepper rhizosphere soil in a residual dry pepper core producing area, culturable microorganisms are screened, and the problem of poor environmental adaptability of a microbial agent is avoided; on the basis of sequencing data, an interaction network is constructed, available microorganisms are found out, synthetic communities are constructed, and the effects of promoting growth and improving quality can be achieved while it is guaranteed that the synthetic communities can be effectively planted.

Description

Technical Field

[0001] This application belongs to the field of microbial technology, and specifically relates to a method for constructing a rhizosphere soil microbial synthetic community for improving the fruit quality of Yugan chili peppers. Background Art

[0002] Chili peppers (Capsicum annuum L.), as an important economic crop globally, their fruit quality is significantly affected by the structure of the rhizosphere soil microbial community. In recent years, Synthetic Microbial Communities (SynComs) technology has become an emerging strategy for improving crop yield and quality by directionally regulating the rhizosphere microbial composition (Zhang et al., 2020, *Nature Biotechnology*). Research has shown that combinations of specific functional strains (such as nitrogen-fixing bacteria, phosphate-solubilizing bacteria, siderophore-producing bacteria) can synergistically improve the plant root microenvironment and promote the accumulation of secondary metabolites (Chen et al., 2022, *Frontiers in Microbiology*). However, existing SynComs designs mostly focus on the general goal of increasing yield, and there has been no reported research on the targeted regulation of the edible quality of chili pepper fruits (such as capsaicin, vitamin C, soluble sugar content).

[0003] Yugan chili peppers, as a geographical indication product in Jiangxi Province, have a unique fruit flavor but are susceptible to continuous cropping obstacles. In the prior art, a special compound microbial inoculant for chili peppers, containing 5 strains such as Bacillus subtilis and Trichoderma, has been disclosed, which can increase the content of soil organic matter. However, this inoculant does not screen strains for the fruit flavor substance synthesis pathway. The research in the 3rd issue of *China Vegetables* in 2023 shows that although single application of phosphate-solubilizing bacteria can increase the yield of chili peppers, it will cause a 15% decrease in the capsaicin content of the fruits. In addition, traditional microbial inoculants generally have strong antagonistic effects between strains and poor rhizosphere colonization stability (Zhao et al., 2021, *Applied and Environmental Microbiology*). Therefore, there is an urgent need to develop a new method. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and provide a method for constructing a rhizosphere soil microbial synthetic community for improving the fruit quality of Yugan chili peppers. Specifically, the following technical solutions are adopted: In the first aspect, the present invention provides a method for constructing a rhizosphere soil microbial synthetic community for improving the fruit quality of Yugan chili peppers, including the following steps: S1. Select chili peppers from different regions of Yugan and detect their edible fruit quality to obtain edible quality indicators; S2. Select the rhizosphere soil of peppers in regions with good quality according to the edible quality indicators, screen the microorganisms, and identify the genus information of the microorganisms; S3. Conduct a correlation analysis between the microorganisms screened in S2 and the best edible quality indicators obtained in S1 to obtain the association information between the microbial strains and the edible quality, and screen out the strains that can promote the quality of Yugan peppers according to the association information, and synthesize the microbial community.

[0005] As a further preferred embodiment, the different regions of Yugan in S1 include one or more of Shuanggang Town, Baimaqiao, Yangbu, Jianshuang, Fuwan, Zhao Family, Leiwan, Fanshang, and Nantang.

[0006] As a further preferred embodiment, the fruit edible quality includes soluble sugar, soluble protein, and crude fat content.

[0007] As a further preferred embodiment, the region with good quality is the region with the best edible quality indicators among the peppers in different regions of Yugan in S1.

[0008] As a further preferred embodiment, the steps of separating and screening the microorganisms in the rhizosphere soil of Yugan peppers in S1 are as follows: Take the rhizosphere soil of Yugan peppers and place it in a phosphate buffer solution, mix well, then perform gradient dilution, spread the diluted solution on the surface of the culture medium, culture, and purify to obtain different microorganisms respectively.

[0009] As a further preferred embodiment, the culture medium includes solid media of TSB, LB, and NA.

[0010] As a further preferred embodiment, the culture temperature is 28°C; the culture time is 48h - 72h.

[0011] As a further preferred embodiment, the steps of conducting a correlation analysis between the microorganisms screened in S2 and the best edible quality indicators obtained in S1 to obtain the association information between the microbial strains and the edible quality are as follows: Use the Mantel - test for analysis. Through multi - omics association analysis, based on multi - omics quantitative data, draw the correlation heat map within the omics and the combined correlation heat map of the network diagram between omics to evaluate the correlation between the microbial strains and the pepper fruit quality, and obtain the association information between the microbial strains and the edible quality.

[0012] As a further preferred embodiment, the correlation r of the association information between the microbial strains and the edible quality is ≥0.6.

[0013] As a further preferred embodiment, the microbial community includes Serratia, Stenotrophomonas, Achromobacter, and Pseudomonas.

[0014] The beneficial effects of the present invention are as follows: (1) Starting from the development of microbial resources in the rhizosphere soil of peppers in the core production area of Yugan peppers, the present invention screens culturable microorganisms to avoid the problem of poor environmental adaptability of microbial agents; based on sequencing data, an interaction network is constructed to identify available microorganisms, and a synthetic community is constructed. While ensuring the effective colonization of the synthetic community, it can also play a growth-promoting role.

[0015] (2) First, the present invention constructs the chemical substance basis of the edible quality of Yugan peppers and quantifies it, providing scientific data support for subsequent improvement and filling the gap; secondly, taking the increase in the content of characteristic quality chemical substances as an anchor point, a microbial agent combination related to it is developed, which is targeted. Brief Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 Shows the soluble sugar content of Yugan pepper fruits; Figure 2 Shows the soluble protein content of Yugan pepper fruits; Figure 3 Shows the crude fat content of Yugan pepper fruits; Figure 4 Shows the analysis result diagram of the correlation between the selected species and the edible quality; Figure 5 Shows the schematic diagram of the purification culture of beneficial strains separated and screened from the soil; Figure 6 Shows the predicted proportion of the functions of the member strains of the synthetic community; Figure 7 Shows the detection graph of the growth curve of the selected strains; Figure 8 Shows the photo of the pepper fruits after inoculation with the synthetic community. The left side is the inoculation, and the right side is the control; Figure 9 Shows the photo of the pepper seedlings after inoculation with the synthetic community. The left side is the inoculation, and the right side is the control; Figure 10 Shows the comparison of the quality of the pepper fruits after inoculation with the synthetic community. The SC group is the inoculation, and the CK group is the control. Detailed Embodiments

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0019] Example 1 A method for constructing a rhizosphere soil microbial synthetic community for improving the fruit quality of Yugan peppers, the specific steps are as follows: Step 1: Select peppers from different production areas for food quality detection, specifically as follows: (1) Measurement of soluble sugar (using anthrone colorimetry): Accurately weigh 0.10 g of fresh sample powder of pepper fruits (from different regions) into a 2 mL centrifuge tube, add 1.5 mL of distilled water, boil in a water bath for 20 min, take out and cool to room temperature, centrifuge at 14000 RPM for 5 min, take the supernatant into a 10 mL volumetric flask, re-extract the residue once, combine the supernatants, and make up to 50 mL with distilled water. Take 0.1 mL of the extract, add 0.5 mL of anthrone reagent, shake well quickly and then boil in a water bath for 10 min, take out and cool to room temperature. Using the glucose standard solution without addition as a blank control, measure the absorbance at a wavelength of 620 nm. Calculate the soluble sugar content in the sample according to the standard curve established by the concentration and absorbance of the prepared standard products. The results are as Figure 1 shown.

[0020] (2) Measurement of soluble protein (using Coomassie brilliant blue method): Accurately weigh 0.3 g of fresh sample powder of pepper fruits (from different regions) into a 10 mL centrifuge tube, add 2.5 mL of distilled water, ultrasonically extract at 30 °C for 15 min, centrifuge at 2000 RPM at 4 °C for 20 min, and take the supernatant; re-extract once and combine the supernatants for measurement. Take 200 μL of the supernatant into a 1.5 mL centrifuge tube, add 1.0 mL of Coomassie brilliant blue reagent, vortex and mix well, and react at room temperature for 2 min. Measure the absorbance of each well at a wavelength of 595 nm using an enzyme-labeled instrument within 5 - 20 min, and calculate the soluble protein content in the sample according to the standard curve established by the concentration (bovine serum albumin) and absorbance of the standard product. The results are as Figure 2 shown.

[0021] (3) Determination of crude fat content: Accurately weigh 0.5 g of dry sample powder of pepper fruits (from different regions), place it in a 50 mL centrifuge tube, add 4 mL of distilled water, mix well, then add 5 mL of hydrochloric acid, and heat in a water bath at 80 °C for 50 min, shaking once every 10 min until the sample is completely digested. Take out the centrifuge tube, add 5 mL of ethanol and mix well. After cooling, add 12.5 mL of petroleum ether, close the lid and shake for 1 min. Slightly open the plug to release the gas, then close it again and let it stand for 15 min; open the plug again, use petroleum ether to rinse the attached fat, let it stand for 15 min. After clear stratification, suck out the supernatant into a pre-weighed centrifuge tube, add another 2.5 mL of petroleum ether, shake, let it stand, and then suck out the upper layer of petroleum ether and put it into the original centrifuge tube. Recover the petroleum ether. When the solvent in the bottle remains about 5 mL, evaporate it to dryness in a water bath, then dry it at 100 °C for 1 h, place it in a dry container and cool for 0.5 h before weighing. Repeat the above operations until constant weight (until the weighing error between two times does not exceed 2 mg), and calculate the crude fat content.

[0022] The different regions of Yugan in the above detection are Shuanggang Town (abbreviated as YC), Baimaqiao (abbreviated as BM), Yangbu (abbreviated as YB), Jianshuang (abbreviated as JS), Fuwan (FW), Zhaojia (abbreviated as ZJ), Leiwan (abbreviated as LW), Fanshang (abbreviated as FS), and Nantang (abbreviated as NT) in the core production area respectively.

[0023] The overall range of the above-detected Yugan peppers and the best pepper edible quality indicators in the core production area of Yugan are shown in Table 1; Table 1 From the attachment Figure 1-3 Combined with the data in Table 1, it can be seen that the pepper indicators of Shuanggang Town in the YC group are better. Therefore, the YC group - Shuanggang Town in the core production area is selected for the next step of microorganism screening. Step 2: Isolate and screen the microorganisms in the rhizosphere soil of the core production area of Yugan peppers and determine their species. The specific process is as follows: (1)Bacterial isolation and culture method: Take 5 g of rhizosphere soil from the YC group, transfer it into 50 mL of sterilized phosphate buffered saline (PBS), and mix it evenly at 25 RPM for 10 min in a constant temperature shaker; then perform gradient dilution, with the dilution range from 10-3 to 10-7. Take 200 μL of the diluted solution and spread it on the surface of solid media of TSB, LB, and NA, and culture it at 28°C for 48 to 72 h; use a sterile inoculation loop to pick colonies with different dilution gradients and different morphological characteristics and growth patterns on each medium, and purify them three times through the TSB solid medium to finally obtain single colonies; inoculate the purified single colonies into a sterile TSB liquid medium and incubate them at 200 RPM in a 28°C constant temperature shaker for 24 h; use a porcelain bead strain preservation tube to preserve the strains at -80°C (the schematic diagram of the purification culture of beneficial strains separated and screened from the soil is as shown in Figure 5 shown).

[0024] (2)The Sanger method was used for strain identification, and the details are as follows: a. DNA extraction: Use the Qiagen DNeasy bacterial genomic DNA extraction kit, and detect the DNA purity (A260 / A280 ≈ 1.8 - 2.0) and concentration (>10 ng / μL) by a spectrophotometer (NanoDrop); b. PCR amplification of target genes: Use the universal 16S rRNA primers 27F (5′-AGAGTTTGATCMTGGCTCAG-3′) and 1492R (5′-TACGGYTACCTTGTTACGACTT-3′) c. PCR system (50 μL): 1 - 10 ng of template DNA, 1 μL of each primer (10 μM), 0.5 - 1 U Taq DNA polymerase, 5 μL of buffer (containing Mg²⁺), add ddH2O to 50 μL; d. PCR program: Pre-denaturation: 95°C, 5 min, cycle (30 - 35 rounds): 95°C 30 s → 55°C 30 s → 72°C 1 min / kb, final extension: 72°C, 5 min; e. Purification of PCR products: Use the Qiagen QIAquick PCR purification kit to remove unbound primers and dNTPs (or recover the target band by cutting the gel through agarose gel electrophoresis); f. Sanger sequencing: The purified PCR products (concentration ≥ 20 ng / μL, volume ≥ 10 μL) are subjected to bidirectional sequencing using forward or reverse primers (usually 27F or 1492R), (with higher precision than unidirectional sequencing), and the ABI 3730xl sequencer is used with the BigDye terminator chemistry method; g. Sequence analysis: Use Chromas or FinchTV to check the quality of the sequencing chromatogram and remove low-quality sequences; align the 16S rRNA sequences in NCBI BLAST (https: / / blast.ncbi.nlm.nih.gov / ), and select the most matching reference sequences (similarity ≥ 99% can be regarded as the same species, 97 - 99% may be different species within the genus). After completing the above steps, the information of the strains isolated and purified from the soil can be obtained.

[0025] Step 3: Conduct a correlation analysis between the microorganisms obtained in Step 2 and the edible quality indicators (YC group - Shuanggang Town) obtained in Step 1, screen out the strains that can promote the quality of Yugan chili peppers, and synthesize a microbial community. The specific process is as follows: Perform the analysis through Mantel - test (analysis software package and version: R version 4.2.0, function package and version: ggcor 0.9.8.1), apply it to multi - omics association analysis, and based on the multi - omics quantitative data, draw the correlation combined heatmaps within the omics (correlation heatmap) and between the omics (network diagram) to evaluate the correlation between microbial strains and chili fruits. The analysis results are as Figure 4 shown.

[0026] According to the correlation between the selected microorganisms and the edible quality, three combinations were initially designed (as Figure 6 shown): 1: Nine strains from 1 to 9; 2: Select one strain with the fastest growth rate from each genus (1, 4, 5, 7); 3: Nine strains from 1 to 9 plus one commercial strain (CK). It was found that the functional prediction of the combination of nine strains was stronger in terms of amino acid and carbohydrate metabolism. Therefore, these nine strains were used to form a microbial community (the growth curves of the 9 selected strains are as Figure 7 shown), and as can be seen from the figure, Serratia significantly promoted the aroma quality and edible quality of Yugan chili peppers, and Stenotrophomonas was significantly positively correlated with the edible quality. Figure 7Among them, PGPB1 is Serratia _1, PGPB2 is Serratia _2, PGPB3 is Serratia _3, PGPB4 is Stenotrophomonas _4, PGPB5 is Stenotrophomonas _5, PGPB6 is Achrombacter _6, PGPB7 is Achrombacter _7, PGPB8 is Pseudomonas _8, PGPB9 is Stenotrophomonas _9, and the CK group is the commercially available Bacillus subtilis (purchased from Jiangxi Ruibote Biotechnology Co., Ltd.).

[0027] The growth-promoting ability of the above strains was detected, and the proportion analysis of the functional abundances of each combination is shown in Table 1; Table 1 Among them, the above _1, _2, _3...._8, _9 are the numbers assigned to the 9 selected strains for easy distinction.

[0028] Example 2 The microbial community screened in Example 1 was verified for its effect (1) Nine purified strains of the genera Serratia and Stenotrophomonas screened in Example 1 were selected to construct a SynCom. The purified strains were separately inoculated into sterilized TSB liquid medium and continuously incubated at 28 °C and 180 rpm for 5 days. Then, another selection of purified strains was incubated under the same conditions for 48 h. The strains from the two incubations were mixed in equal amounts, the OD600 value was adjusted to 0.5, and the cells were collected by centrifugation at 5000 rpm for 10 min at 4 °C. After re-extraction once, the cells were resuspended in 20 mL of sterile water for inoculation.

[0029] (2) SynCom inoculation method: After surface sterilization of the Yuliang pepper seeds, they were sown in pots containing the original soil (collected from the original pepper planting base) for seedling raising. Healthy seedlings with a plant height of 5 cm were selected, and 20 mL of the resuspended SynCom bacterial suspension was irrigated at the roots. The control group was inoculated with the same volume of sterile water. At the early flowering stage of the pepper seedlings (when the diameter of the first flower bud reached 2 mm), the inoculation group and the control group were inoculated with the bacterial suspension again. The experiment adopted a completely randomized block design, with a SynCom treatment group (SC group) and a sterile water control group (CK group). Each group contained 5 biological replicates, and each replicate unit contained 30 uniformly growing seedlings, for a total of 300 plants.

[0030] For the collection of the above growth and development trait data (the results are shown in Table 2), on the 10th day after the first inoculation treatment, the following growth phenotypes were measured: (1) plant height, the vertical height from the substrate surface to the apical bud growth point; (2) stem diameter, the stem diameter at 1.0 cm below the cotyledon node; (3) main root length, the straight-line distance from the root neck to the root tip; (4) the time of first flower, the cumulative number of days from the inoculation day to the first flower bud being visible (corolla diameter ≥ 2 mm). Five independent biological replicates were set for each treatment group (the total sample size was 25 plants in the SC group and 25 plants in the CK group), and the data collection followed the principle of a single-blind experiment.

[0031] Table 2 (3)After the peppers are mature, the edible quality is detected as follows: ① For the measurement of soluble sugar, the anthrone colorimetric method is used, and the steps are as follows: Accurately weigh 0.10 g of fresh pepper fruit sample powder (FW) into a 2 mL centrifuge tube, add 1.5 mL of distilled water, place it in a boiling water bath for 20 min, take it out and cool to room temperature, centrifuge at 14,000 rpm for 5 min, take the supernatant into a 10 mL volumetric flask, re-extract the residue once, combine the supernatants, and make up the volume to 50 mL with distilled water. Take 0.1 mL of the extract, add 0.5 mL of anthrone reagent, shake well quickly and then place it in a boiling water bath for 10 min, take it out and cool to room temperature, use the blank control without adding the glucose standard solution, and measure the absorbance value at a wavelength of 620 nm. Calculate the soluble sugar content in the sample according to the standard curve established by the concentration of the standard product and the absorbance.

[0032] ② For the measurement of soluble protein, the Coomassie brilliant blue method is used, and the steps are as follows: Accurately weigh 0.3 g of fresh pepper fruit sample powder (FW) into a 10 mL centrifuge tube, add 2.5 mL of distilled water, ultrasonically extract at 30℃ for 15 min, centrifuge at 4℃ and 2000 rpm for 20 min, and take the supernatant; re-extract once and combine the supernatants for testing. Take 200 μL of the supernatant into a 1.5 mL centrifuge tube, add 1.0 mL of Coomassie brilliant blue reagent, vortex and mix well, and react at room temperature for 2 min. Measure the absorbance of each well at a wavelength of 595 nm within 5 - 20 min using an enzyme-linked immunosorbent assay reader, and calculate the soluble protein content in the sample according to the standard curve established by the concentration of the standard product (bovine serum albumin) and the absorbance.

[0033] ③For the determination of crude fat content, the operating steps are as follows: Accurately weigh 0.5 g of dry sample powder (DW) of pepper fruits, place it in a 50 mL centrifuge tube, add 4 mL of distilled water, mix well, then add 5 mL of hydrochloric acid, and heat in a water bath at 80 °C for 50 min, shaking once every 10 min until the sample is completely digested. Take out the centrifuge tube, add 5 mL of ethanol and mix well. After cooling, add 12.5 mL of petroleum ether, close the lid and shake for 1 min. Slightly open the plug to release the gas, then close it again and let it stand for 15 min; open the plug again, use petroleum ether to rinse the attached fat, let it stand for 15 min. After clear stratification, aspirate the supernatant into a pre-weighed centrifuge tube, add another 2.5 mL of petroleum ether, shake, let it stand, and then aspirate the upper layer of petroleum ether and put it into the original centrifuge tube. Recover the petroleum ether. When about 5 mL of the solvent remains in the bottle, evaporate it to dryness in a water bath, then dry it at 100 °C for 1 h, place it in a dry container and cool for 0.5 h before weighing. Repeat the above operations until constant weight (until the weighing error between two times does not exceed 2 mg), and calculate the crude fat content.

[0034] ④Measurement of total phenols and total flavonoids: Accurately weigh 0.5 g of fresh sample powder (FW) of pepper fruits and dissolve it in 12 mL of 70% methanol solution. Vortex and mix well for 20 s, ultrasonicate at room temperature for 30 min, centrifuge at 14000 rpm for 15 min at 4 °C, transfer the supernatant to a blank centrifuge tube, extract again, take the supernatant, combine the supernatants and filter through a 0.22 μm filter membrane for storage.

[0035] The determination of total phenol content adopts the Folin-Ciocalteu method, and the steps are as follows: Take 200 μL of the test solution in a centrifuge tube, add 1 mL of 0.2 mol / L Folin-Ciocalteu reagent and mix well, place it in the dark for 10 min, add 800 μL of 7.5% Na2CO3 solution, react for 30 min, use a microplate reader to measure the absorbance of each well at a wavelength of 765 nm, and calculate the total phenol content in the sample according to the standard curve established by the concentration and absorbance of the standard product (gallic acid).

[0036] The determination of total flavonoid content adopts the aluminum salt colorimetric method, and the steps are as follows: Take 500 μL of the test solution in a centrifuge tube, add 0.5 mL of 70% ethanol, mix well, then add 150 μL of 5% NaNO3, react for 6 min, add 150 μL of 10% Al(NO3)3 solution, after 1 min, add 1 mL of 1 mol / L NaOH solution, react for 15 min, use a microplate reader to measure the absorbance of each well at a wavelength of 510 nm, and calculate the total phenol content in the sample according to the standard curve established by the concentration and absorbance of the standard product (rutin).

[0037] The total phenol / total flavonoid content of the sample is calculated by the following formula: Where: C—the content of total phenols or total flavonoids (mg / g), C1—the concentration of gallic acid or rutin equivalent in the reaction solution (mg / mL), V—the volume of the extraction solution (mL), N—the dilution factor of the sample; m—the mass of the sample (g).

[0038] ⑤ Measure the cellulose content as follows: Accurately weigh 0.1 g of fresh sample (FW) powder into a 5 mL EP tube, add 3 mL of 50% H2SO4 solution, place it in an ice-water bath for 40 min, centrifuge at 8000 rpm for 5 min, and take the supernatant. Pipette 200 μL of the supernatant into a 1.5 mL centrifuge tube, add 50 μL of 2% anthrone solution, add 500 μL of concentrated sulfuric acid solution along the tube wall, cover the cap and shake well, heat in a boiling water bath for 5 min, and let it stand and cool. Measure the absorbance at a wavelength of 620 nm, and calculate the cellulose content in the sample using the standard curve calculated from the standard product concentration and absorbance. The above test results are as Figure 8-10 shown. It can be seen from the results that the inoculation of SynCom significantly promoted the growth of pepper seedlings and improved the edible quality of peppers. The edible quality indexes of the fruits, such as the contents of soluble sugar, soluble protein, crude fat, total phenols, and total flavonoids, were all significantly increased (p<0.01).

[0039] The embodiments of the present application have been described above in conjunction with the accompanying drawings. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the core idea of the present application. However, the present application is not limited to the above specific implementation manners. The above specific implementation manners are only illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all belong to the protection scope of the present application.

Claims

1. A method for constructing a synthetic community of rhizosphere soil microorganisms for improving the quality of Yugan pepper fruit, characterized in that: The following steps are involved: S1. Select peppers from different regions of Yugan, and test the edible quality of their fruits to obtain edible quality indicators; S2. Select pepper rhizosphere soil from regions with good quality according to edible quality indicators, isolate and screen microorganisms, and identify the species information of the microorganisms; S3. Perform correlation analysis on the microorganisms screened by S2 and the best edible quality index obtained by S1 to obtain the correlation information between the microbial strains and the edible quality, and screen out the strains that promote the quality of Yugan peppers based on the correlation information, and synthesize the microbial community.

2. The construction method according to claim 1, characterized in that: The different areas of Yugan mentioned in S1 include one or more of Shuanggang Town, Baimaqiao, Yangbu, Jianshuang, Fuwan, Zhaojia, Leiwan, Fanshang, and Nantang.

3. The construction method according to claim 1, characterized in that: The edible quality of the fruit includes soluble sugar content, soluble protein content, and crude fat content.

4. The construction method according to claim 1, characterized in that: The areas with good quality are the areas with the best edible quality indicators among the peppers in different areas of Yugan in S1.

5. The construction method according to claim 1, characterized in that: The steps for separating and screening the microorganisms in the rhizosphere soil of Yugan pepper described in S1 are as follows: The rhizosphere soil of the remaining dried peppers is placed in a phosphate buffer solution, mixed evenly, and then gradiently diluted. The diluted soil is spread on the surface of the culture medium, cultured, purified, and different microorganisms are obtained respectively.

6. The construction method according to claim 3, characterized in that: The culture medium includes solid culture medium of TSB, LB and NA.

7. The construction method according to claim 3, characterized in that: The culture temperature is 28°C; the culture time is 48h-72h.

8. The construction method according to claim 1, characterized in that: The steps of performing correlation analysis on the microorganisms screened by S2 and the best edible quality index obtained by S1 to obtain the correlation information between the microbial strains and the edible quality are as follows: Mantel-test was used for analysis. Based on multi-omics quantitative data, a correlation combination heat map of intra-omics correlation heat map and inter-omics network map was drawn to evaluate the correlation between microbial strains and pepper fruit quality, and to obtain the association information between microbial strains and edible quality.

9. The construction method according to claim 8, characterized in that: Correlation of association information between microbial strains and edible quality r ≥ 0.

6.

10. The construction method according to claim 1, characterized in that: The microbial community includes Serratia, Stenotrophomonas, Achromobacter, and Pseudomonas.

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