谷氨酰半胱氨酸合成酶对阿特拉津胁迫下紫花苜蓿耐受力和修复力的影响机制研究

Atrazine (ATZ) is a triazine herbicide widely used worldwide. Due to its long half-life in soil, crop rotation is disturbed and soil microbial community diversity is reduced. ATZ soil contamination and its negative effects on the entire ecosystem need to be solved urgently. Studies have shown that glutamylcysteine synthetase (γECS) can enhance plant stress resistance and improve phytoremediation ability, but the mechanism of γECS regulation of phytotoxicity and metabolic degradation of pesticides is still unclear. In this project, ATZ is selected as the tested pesticide, and alfalfa is used as the research material to study the γECS gene MsECS1 which was significantly up-regulated by ATZ stress. By studying the mechanism of MsECS1 on the toxicity of alfalfa under the stress of ATZ and the mechanism of MsECS1 on the absorption, accumulation and metabolism of ATZ in alfalfa, the γECS regulation of the tolerance of alfalfa to ATZ will be systematically described. In addition, the repair function of MsECS1 on ATZ pollution is tested in a small plot field. The study will provide a theoretical reference for establishing a new approach to pesticide pollution control based on enhanced endogenous detoxification metabolism.

阿特拉津（ATZ）是世界范围内广泛使用的除草剂。因其在土壤中的半衰期长，导致作物轮作障碍以及土壤微生物群落多样性降低，ATZ对土壤的污染及其对整个生态系统的负面效应是迫切需要解决的问题。研究表明，谷氨酰半胱氨酸合成酶（γECS）能增强植物抗逆性，提高植物对土壤污染的修复能力，但关于γECS调控植物毒性作用和代谢降解农药的机理尚不清楚。本项目拟选用ATZ为供试农药，以紫花苜蓿为研究材料，针对申请人在前期研究中发现的受ATZ胁迫显著上调表达的γECS基因MsECS1开展研究。通过研究MsECS1对ATZ胁迫下紫花苜蓿毒性作用的影响机制，以及MsECS1对紫花苜蓿吸收、积累和代谢ATZ的影响机制，系统阐述γECS调控紫花苜蓿对ATZ耐受力和修复力的作用机理。此外，通过小块试验田检验MsECS1对ATZ污染的修复功能，以期为建立一条基于强化内源解毒代谢的农药污染控制新途径提供理论参考。

阿特拉津（ATZ）是世界范围内广泛使用的除草剂。因其在土壤中的半衰期长，导致作物轮作障碍以及土壤微生物群落多样性降低，ATZ对土壤的污染及其对整个生态系统的负面效应是迫切需要解决的问题。本项目的研究表明阿特拉津对紫花苜蓿不同部位的毒性作用不同，对顶端部位毒性最高；且紫花苜蓿顶端部位对阿特拉津的积累量最高；紫花苜蓿根部对阿特拉津代谢物的分泌有较大差异。项目构建了MsECS1转基因株系，过表达植株体内的积累量和土壤中的阿特拉津残留量低于野生型。研究表明，MsECS1缓解了阿特拉津对紫花苜蓿的毒性，且促进了紫花苜蓿对阿特拉津的代谢；过表达株系的半胱氨酸S-结合物和高谷胱甘肽S-结合物的含量显著高于野生型。本项目明确了γECS对紫花苜蓿代谢降解农药的调控机制，创造了一条基于强化植物内源解毒代谢的农药污染控制新途径，推动了植物修复有机污染物领域的研究。