水杨酸促进若干农作物体内残留农药代谢与降解机制的研究

Pesticide residues exceeding the standard in agricultural field and crops affect quality of grains and food safety. Degradation and removal of pesticide residues are important for crop production. In this project, we will investigate the role of salicylic acid (SA) in regulating metabolism and degradation of thiamethoxam, atrazine and isoproturon pesticide residues in rice, wheat and rape. Structural characterization and quantification of SA, pesticides and their catabolites in plant tissues will be performed using chromatography, ELISA, spectral mass or tandem mass spectrometry and subcellular isolation techniques. We will also analyze the effect of the abundance of SA on the accumulation of pesticide residues and ligand structures. Isolation and characterization of genes ICS (encoding isochorismate synthase) and PAL (encoding phenylalanine ammonia lyase) of SA biosysthesis will be performed to analyze the expression of the genes contributes to the degradation of pesticides. Comparitive studies will be made on the correlation between the expresion of ICS and PAL, level of SA, pesticide toxicity, accumulation and degradation in grains of different crops. The purpose of the project is to figure out the mechanism that SA is responsible for the pesticide degradation and regulation of the low accumulation of the pesticides in the crop grains.

农田土壤和农作物中残留农药超标直接影响粮食生产与食品安全。探明农作物中残留农药降解机制、探索降低农药残留技术与方法是保障粮食安全生产的有效途径。本项目以水稻、小麦和油菜为主要作物，以噻虫嗪、阿特拉津和异丙隆为代表农药，研究水杨酸（Salicylic acid, SA, 植物中一种天然生长调节剂）对农作物和籽粒中残留农药代谢及降解的调控机制。采用色谱、色谱-质谱联用、酶联免疫及14C示踪等技术分析不同农作物及品种中SA对残留农药积累的影响，分析和鉴定SA在农作物体内对残留农药降解产物含量及结合物结构的影响。解析SA调节供试作物体内农药代谢与降解途径。分离和鉴定控制SA生物合成酶基因（ICS和PAL），研究这些基因及酶调控作物体内有毒农药代谢与降解功能。比较研究作物不同品种间ICS和PAL表达差异与籽粒中残留农药积累、毒性及降解之间的关系，最终阐明SA加速作物体内残留农药降解或低积累的机理。

农田土壤和农作物中残留农药超标直接影响粮食生产与食品安全。探明农作物中残留农药降解机制、探索降低农药残留技术与方法是保障粮食安全生产的有效途径。本项目以水稻、小麦和油菜为主要作物，以阿特拉津、异丙隆等为代表农药，研究了水杨酸（Salicylic acid, SA）对水稻、小麦和油菜，以及水稻籽粒中残留农药代谢及降解的调控机制。鉴定了控制水杨酸生物合成酶基因（ICS和PAL），获得了影响水杨酸生物合成酶基因的突变体。对比分析了突变体与野生型水稻对供试残留农药的生物毒性反应、作物及籽粒中农药积累量变化、残留农药降解产物含量及结合物结构差别，毒性及降解之间的关系。研究结果显示，与野生型相比，残留农药对突变体植物的毒性高，生长缓于野生型，突变体体内尤其是籽粒中农药积累量高于野生型，而降解与代谢产物的相对量又显著低于野生型等。从而明确了水杨酸调节作物体内农药代谢与降解途径。与此同时，又用野生型拟南芥和控制水杨酸生物合成的两种酶基因（ICS和PAL）的拟南芥突变体进行了研究，进一步验证了水杨酸调节植物体内农药代谢与降解的功能。最终阐明了水杨酸加速作物体内残留农药降解和低积累的机理。