手性除草剂干扰土壤根系微生物群落结构及多样性的对映体选择性

Soil is by far the most microbially diverse habitat on Earth. Soil microbes play key roles in ecosystems and influence food safety, carbon and nitrogen fixation, while rhizosphere microorganisms, surrounding and influenced by plant roots, is a hot spot for numerous organisms and is considered as one of the most complex ecosystems on Earth. They are beneficial to plant growth and health, help plants adapt to the surrounding environment, absorb nutrients and resist in diseases and insect pests through the unique molecular signals. Chiral is a natural attribute, all life activity often exists enantioselectivity. Chiral herbicides are common environmental stress factors, and their toxicological studies mainly focus on the effects on plant growth. However, basic research chiral herbicide effect on soil microecosystem is still lacking. This project will take the Arabidopsis thaliana as an model plant to understand the enantioselective effects of chiral herbicides on soil root microorganisms by means of a variety of molecular ecology techniques. We will analyze the following points systematically: (1) the mechanism of chiral herbicides inducing plant root exudates; (2) the mechanism of active secretions on rhizosphere microbial community and diversity. This project will help us to understand the comprehensive effects of chiral herbicides on plant growth, soil microbial diversity and ecological balance. At the same time, it is the key objective to research the toxicity and environmental risks of chiral herbicides and to promote sustainable development of chiral pesticides.

土壤是地球上最多样的微生物栖息地，土壤微生物是食品安全和碳氮固定之关键，而寄居于根系间的根系微生物则通过独特的分子信号帮助植物适应周围环境，吸收营养，抵御病虫害，是农业可持续性生产的关键角色。手性是自然属性，一切涉及生命活动的过程往往存在对映体选择性。手性除草剂是常见环境胁迫因子，其毒理学研究主要集中在对植物生长的影响，但就其改变土壤根系微生态的基础研究仍缺失。因此，在对映体水平上研究手性农药对土壤微生物的环境效应是有意义的。本项目将以拟南芥为例，借助多种分子生态研究技术，了解手性除草剂对土壤根系微生物的对映体选择性影响，系统分析：(1)手性除草剂诱导植物根系分泌物的种类及诱导机制；（2）活性分泌物对根际微生物的群落和多样性影响的作用机制。本项目研究将帮助我们全面了解手性除草剂对植物生长、土壤微生物的多样性及生态平衡的影响。加强手性除草剂的土壤环境效应与风险的研究，促进手性农药的健康发展。

本项目旨在研究手性除草剂对植物根系分泌物及土壤根系微生物种群结构和多样性的影响。研究发现异丙甲草胺和咪唑乙烟酸均可能够以对映体选择性调节根际代谢产物，从而选择性塑造根际微生物群落。此外，2, 4-滴丙酸对植物的生长、氧化酶活和光合作用等生理活动的影响呈现对映体选择效应，喷洒改手性农药可通过改变植物叶片代谢活动，实现对植物叶际微生物群落调控。手性除草剂均显著改变植物的共生微生物（包括根际和叶际）群落组成，特别是可能导致叶际潜在致病细菌的相对丰度增加。项目的科学意义主要包括：①通过对叶际微生物组、根际微生物组的共同分析，使对除草剂环境风险评估研究更加全面、具体。②将16S rRNA高通量测序和代谢组学技术相结合，从根际微生物群落结构和代谢变化两方面进行分析，揭示根际群落变化的内在原因。项目共发表SCI收录论文20篇，其中部分发表在农药学学报、Microbiome, Commun Biol, Environ Pollut, J Agric Food Chem, J. Hazard. Mater等环境领域知名期刊上。