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CN-121978039-A - Method for analyzing selenium fertilizer to regulate and control rhizosphere microorganism driving mechanism of rape cadmium accumulation

CN121978039ACN 121978039 ACN121978039 ACN 121978039ACN-121978039-A

Abstract

The invention is suitable for the technical field of agricultural environment microbial ecology and heavy metal pollution restoration and intersection, and provides a method for analyzing a rhizosphere micro-domain microbial driving mechanism of selenium fertilizer for regulating and controlling rape cadmium accumulation. By measuring Cd/Se content of plants and soil, rhizosphere microbial community structure, abundance of functional genes (dsrA) and microorganism-environmental factor correlation analysis, the system reveals a microorganism mechanism that selenium fertilizer (500-1000 g Se/hm 2 ) enriches key functional microorganisms such as the desulphurizer phylum and geobacillus through driving rhizosphere, and greatly improves sulfate reducing capacity (dsrA gene abundance is increased by 250%), so that cadmium biological effectiveness is reduced. The invention provides a methodology and theoretical support for repairing farmland heavy metal pollution by utilizing microbial regulation.

Inventors

  • HUANG LUYAO
  • NIE LINGLI
  • LIU YING
  • Xing man
  • WANG ZEQIAN
  • ZOU YUJING
  • YANG HAIPING
  • WU PING
  • LIAO ZHIQIANG

Assignees

  • 宜春市科学院(江西富硒产业研究院)

Dates

Publication Date
20260505
Application Date
20251222

Claims (10)

  1. 1. A method for analyzing a rhizosphere microorganism driving mechanism of selenium fertilizer for regulating and controlling rape cadmium accumulation is characterized by comprising the following steps: (1) Setting a field test of multi-gradient selenium fertilizer treatment on a cadmium polluted farmland, collecting plants and soil samples in the rape maturity stage, and evaluating the macroscopic effect of the selenium fertilizer; (2) Embedding a rhizosphere compartmental micro-zone device in each cell of the field test, wherein the device comprises an inner chamber for containing rhizosphere soil and an outer chamber for containing non-rhizosphere soil, and the inner chamber is composed of a micropore isolation material capable of physically isolating plant root systems from crossing and allowing moisture, nutrients and signal substances to pass freely; (3) Respectively collecting plant samples, rhizosphere soil and non-rhizosphere soil samples in a field test and a micro-area test, and measuring the cadmium and selenium content of the plant samples; (4) Extracting rhizosphere soil DNA, and carrying out microbial community structure analysis and functional gene abundance quantification; (5) Performing correlation analysis on the differential microorganism group and the selenium content of soil and the cadmium content of plants; (6) By combining all the results, a mechanism that the selenium fertilizer reduces the bioavailability of cadmium by driving the proliferation of the microbial community with specific functions of the rhizosphere is analyzed.
  2. 2. The method for resolving a rhizosphere micro-domain microbial driving mechanism for regulating and controlling cadmium accumulation of rape by using selenium fertilizer according to claim 1, wherein the multi-gradient selenium fertilizer treatment in the step (1) comprises the selenium fertilizer application amount of 0g/hm 2 、500g/hm 2 、1000g/hm 2 .
  3. 3. The method for resolving a rhizosphere micro-domain microbial drive mechanism for regulating cadmium accumulation in canola plants by selenium fertilizer according to claim 1, wherein the pore size of the microporous isolation material in step (2) is 300 mesh or higher.
  4. 4. The method for analyzing selenium fertilizer to regulate and control rhizosphere micro-domain microorganism driving mechanism of rape cadmium accumulation according to claim 1, wherein the microporous isolation material in the step (2) is nylon, metal nylon composite net or polyester net cage.
  5. 5. The method for resolving a rhizosphere micro-domain microbial driving mechanism for regulating and controlling cadmium accumulation of rape by selenium fertilizer according to claim 1, wherein the outer chamber material of the rhizosphere compartmental micro-area device in the step (2) is PVC.
  6. 6. The method for analyzing selenium fertilizer to regulate and control rhizosphere micro-domain microorganism driving mechanism of rape cadmium accumulation according to claim 1, wherein in the step (3), the cadmium content of plants is measured by an atomic absorption spectrometer after digestion by adopting a wet ashing method, and the selenium content of plants is measured by an atomic fluorescence photometer after reduction by adopting nitric acid-perchloric acid decomposition and hydrochloric acid.
  7. 7. The method of claim 1, wherein the microbial community structure analysis in step (4) comprises PLS-DA analysis and LefSe linear discriminant analysis based on high throughput sequencing data of the 16SrRNA gene to identify differential microbial populations specifically enriched under different selenium treatments.
  8. 8. The method of resolving a rhizosphere microbial drive mechanism for selenium fertilizer to regulate cadmium accumulation in canola of claim 7, wherein the specifically enriched differential microbiota comprises a desulphurisation phylum (Desulfobacterota) and geobacillus (Geobacter).
  9. 9. The method for analyzing the rhizosphere micro-domain microbial driving mechanism of the selenium fertilizer for regulating and controlling the cadmium accumulation of rape according to claim 1, wherein the quantitative determination of the abundance of the functional gene in the step (4) is carried out by adopting a real-time fluorescent quantitative PCR technology aiming at the sulfate reduction functional gene dsrA.
  10. 10. The method for analyzing selenium fertilizer to regulate and control rhizosphere micro-domain microbial driving mechanism of rape cadmium accumulation according to claim 1, wherein the analyzed mechanism in the step (6) is that 500-1000g/hm 2 of sodium selenite is applied, the content of rhizosphere selenium is increased, the desulphurizer phylum and the geobacillus genus are specifically enriched, the dsrA gene abundance is remarkably increased, and the bioavailability of cadmium is reduced by enhancing the sulfate reduction process, so that the rape cadmium is reduced.

Description

Method for analyzing selenium fertilizer to regulate and control rhizosphere microorganism driving mechanism of rape cadmium accumulation Technical Field The invention belongs to the technical field of agricultural environment microbial ecology and heavy metal pollution restoration and intersection, and particularly relates to a method for analyzing a rhizosphere micro-domain microorganism driving mechanism of selenium fertilizer for regulating and controlling rape cadmium accumulation. Background Soil cadmium pollution is a global challenge affecting crop safety production. Selenium has been shown to be effective in antagonizing cadmium uptake by crops, but its mechanism of action has long been attributed primarily to interactions at plant physiological levels, such as competing for the site of uptake, activating antioxidant systems, forming Cd-Se complexes, etc. However, how to indirectly regulate the bioavailability of cadmium by remodelling the microbial community structure in the key micro-domain of the rhizosphere is a weak link of current research and is also a key for deeply understanding the antagonism effect of selenium and cadmium. Traditional research methods, such as field tests or common potting, cannot accurately separate rhizosphere soil from non-rhizosphere soil, so that the response of microorganisms is difficult to accurately locate in rhizosphere micro-domains, and the direct physiological effect and the indirect microbial effect of selenium cannot be clearly distinguished. Therefore, the development of the method capable of accurately analyzing the microorganism driving mechanism in the rhizosphere micro-domain has important significance for revealing the deep principle of reducing cadmium in the selenium fertilizer and guiding accurate agricultural practice. Disclosure of Invention The invention aims to provide a method for accurately and systematically analyzing a rhizosphere microorganism driving mechanism of regulating and controlling cadmium accumulation of rape by selenium fertilizer. According to the method, the rhizosphere and non-rhizosphere soil physical separation is realized through the rhizosphere compartmental micro-area device coupling field test, and the key functional microorganism group enriched in selenium fertilizer and the effect thereof in cadmium reduction are defined by combining the microbial community structure analysis, functional gene quantification and correlation analysis. The invention is realized in this way, a method for analyzing selenium fertilizer to regulate and control the microorganism driving mechanism of rhizosphere micro-domain of rape cadmium accumulation, comprising the following steps: (1) Setting a field test of multi-gradient selenium fertilizer treatment on a cadmium polluted farmland, collecting plants and soil samples in the rape maturity stage, and evaluating the macroscopic effect of the selenium fertilizer; (2) Embedding a rhizosphere compartmental micro-zone device in each cell of the field test, wherein the device comprises an inner chamber for containing rhizosphere soil and an outer chamber for containing non-rhizosphere soil, and the inner chamber is composed of a micropore isolation material capable of physically isolating plant root systems from crossing and allowing moisture, nutrients and signal substances to pass freely; (3) Respectively collecting plant samples, rhizosphere soil and non-rhizosphere soil samples in a field test and a micro-area test, and measuring the cadmium and selenium content of the plant samples; (4) Extracting rhizosphere soil DNA, and carrying out microbial community structure analysis and functional gene abundance quantification; (5) Performing correlation analysis on the differential microorganism group and the selenium content of soil and the cadmium content of plants; (6) By combining all the results, a mechanism that the selenium fertilizer reduces the bioavailability of cadmium by driving the proliferation of the microbial community with specific functions of the rhizosphere is analyzed. Preferably, the multi-gradient selenium fertilizer treatment in the step (1) comprises 3 application amounts, namely CK of 0 g/hm 2 (comparison), L of 500 g/hm 2 (low selenium) and H of 1000 g/hm 2 (high selenium), a random block design is adopted in a field test, 3 times of repetition are adopted, the cell area is 15m 2 (5 m multiplied by 3 m), the transplanting density is 30cm multiplied by 30cm, management measures are that the base fertilizer is uniformly applied (N150 kg/hm 2、P2O580 kg/hm2、K2O 120 kg/hm2), the selenium fertilizer is applied on a base after being mixed with the base fertilizer, and the water management refers to the conventional local rape planting (the soil humidity is kept to be 60% -70%) and timely control of plant diseases and insect pests. Preferably, the pore size of the microporous isolation material in the step (2) is 300 meshes or more, which allows free exchange of moisture, nutrie