太子参连作对土传病原菌及其拮抗菌选择性促抑的机制研究

Radix Pseudostellariae L. is a well-known traditional Chinese medicinal plant with the high medicinal value and growing market demand, and predominantly grown in Zherong county, Fujian province known as the geo-authentic production zone. However, Radix Pseudostellariae L. has been shown to suffer from serious replanting disease that causes significant declines in both yield and quality. In this study, on the basis of the obtained soil-born pathogen (Fusarium oxysporum, Serretia marcescens and Enterobacter) and its antagonistic microbe (Bacillus subtilis, Bacillus amyloliquefaciens and Burkholderia) from Radix Pseudostellariae L. rhizosphere soil, the methods of polar resin extraction, thin-layer chromatography (TLC), high performance liquid chromatography/mass spectrum (HPLC/MS), drop assay, swarm plate assay and qRT-PCR were used to study the ecological effects of key rhizosphere secretions on soil-born pathogens and its antagonistic microbe, and the interaction between soil-born pathogen and its antagonistic microbe in the rhizosphere soil of Radix Pseudostellariae L. It’s expected to uncover the mechanism about reduced antagonistic ability of beneficial microbe and expansion of pathogen communities mediated by root exudates of Radix Pseudostellariae L. under the continuous monoculture.

柘荣太子参为药用价值高、市场需求大的福建道地药材，其连作障碍问题突出，是已知块根类药材中连作障碍较为严重的药用植物之一。本研究在前期分离与鉴定得到太子参专化型病原菌与相应拮抗菌的基础上，运用极性大孔吸附树脂收集技术、TLC技术、HPLC/MS技术、滴定分析法（Drop assay）、群游扩散平板法（Swarm plate assay）与qRT-PCR等研究方法与思路，明确关键分泌物对土传病原菌与拮抗菌选择性促进或抑制的生态效应，研究土传病原菌与拮抗菌以及太子参根系关键分泌物在连作根际土壤的互作情况，从而探讨根系分泌物介导下拮抗菌抑菌能力减弱而病原菌生长受促进的根际生态学机制。

本研究以“柘参2号”为材料，运用GC-MS、HPLC 等现代质谱、色谱分析技术，分析太子参根际化感物质在连作根际土壤中的变化情况，并锁定关键根际化感物质。并筛选太子参根际病原微生物与有益拮抗微生物，运用差异转录组学与基因组甲基化分析方法明确关键分泌物对土传病原菌与拮抗菌选择性促进或抑制的生态效应，同时通过研究病原菌与拮抗菌以及太子参根系关键分泌物在根际土壤的互作关系，阐明根系分泌物介导下拮抗菌抑菌能力减弱而病原菌生长受促进的根际生态学过程。在此基础上，通过设计和开展拮抗菌拌种试验和外施专用生物菌肥试验，深入探讨菌肥消减技术对促进太子参连作土壤中微生物多样性提高、改善土壤生态功能等根际生态学机制。由此，通过菌肥消减技术改善连作太子参土壤微生态结构，减缓太子参连作障碍的新策略，可为实现太子参连作障碍的有效控制，逐步解除太子参栽培的瓶颈问题，促进福建太子参产业的可持续发展，提供理论依据和技术支撑。