全氟辛酸（PFOA）低积累生菜品种形成的分子机理研究

Perfluorinated compounds (PFCs), a group of persistent and high-toxic organic pollutants, have been widely detected in soils and vegetables. Edible vegetables have been becoming an important exposure pathway for humans to PFCs, causing serious damage to human health. Selection of the crop cultivars with low accumulation of target pollutants is an effective approach to ensure the safety of agricultural products. However, the previous researches on cultivar selection mainly focus on heavy metals, and few research is available on organic pollutants. The project is proposed to study molecular formation mechanisms in lettuce cultivars with low accumulation of perfluorooctanoic acid PFOA (i.e., low-PFOA lettuce cultivar) using high-PFOA lettuce cultivar as control, based on previous studies on environmental behaviors of PFOA and physiological and biochemical characteristics of the lettuce cultivars. Three objectives of the project are included: (1) to identify the key genes that control characteristics of PFOA accumulation in low-PFOA lettuce cultivars using transcriptome and proteome technologies, (2) to investigate the temporal spatial expression patterns of the key genes and the subcellular localization of their expression proteins, and the interaction mechanism between the expression proteins and PFOA in vitro via molecular simulation and spectroscopy method, and (3) to clarify the function and action mechanism of the key genes in transport and accumulation of PFOA in the two lettuce cultivars using RNA interference and gene overexpression technologies combined with pot experiments. The results of the project are beneficial to provide candidate gene library and genetic materials for molecular breeding of vegetable cultivar with low accumulation of pollutants.

全氟化合物（PFCs）是持久性、高毒性有机污染物，在土壤、蔬菜中普遍检出。食用蔬菜是人体暴露PFCs的重要途径，严重危害人体健康。筛选污染物低积累作物品种是保障农产品安全的重要策略，以往研究主要针对重金属，对于有机污染物鲜见报道。本项目以典型PFCs全氟辛酸（PFOA）和国内外广泛种植的生菜为研究对象，针对筛选获得的PFOA低积累生菜品种，在前期环境行为和生理生化研究的基础上，通过转录组学和蛋白组学技术识别其低积累PFOA形成的关键基因，探讨这些基因的时空表达特异性；构建融合表达系统，查明这些基因表达蛋白的亚细胞定位，并以分子模拟和光谱学手段分析表达蛋白与PFOA的体外互作机制；利用基因沉默表达和过表达技术，并通过盆栽实验，阐明关键基因在生菜积累PFOA过程中的功能和作用机制，从而揭示PFOA低积累生菜品种形成的分子机理，为污染物低积累作物品种的绿色分子选育提供候选基因文库和遗传材料。

全氟化合物（PFCs）是持久性、高毒性有机污染物，在土壤、蔬菜中普遍检出。食用蔬菜是人体暴露PFCs的重要途径，严重危害人体健康。筛选污染物低积累作物品种是保障农产品安全的重要策略，以往研究主要针对重金属，对于有机污染物鲜见报道。本项目以典型PFCs全氟辛酸（PFOA）和全氟辛烷磺酸（PFOS）和国内外广泛种植的生菜为研究对象，筛选获得二者的低积累生菜品种，并从根系分泌物活化、根系形态/结构、根系吸收转运通道、亚细胞分布、蒸腾作用等方面阐明了不同品种生菜吸收积累PFOA和PFOS的多过程生理生化调控机理；利用转录组（RNA-Seq）和蛋白质组联合分析识别了生菜吸收积累PFOA和PFOS的两个关键分子调控途径，即离子通道/转运蛋白参与的吸收转运分子途径以及细胞壁合成代谢基因参与的吸附固定分子途径；针对上述分子调控途径中的关键基因设计引物，查明其表达特性，并通过构建生菜单细胞原生质体瞬时表达系统，查明关键基因的亚细胞定位；利用分子模拟手段分析了PFOA和PFOS与关键基因表达蛋白的互作作用；进一步构建了关键基因的敲除及过表达植株，通过盆栽实验初步验证了关键基因在植物吸收转运PFOA和PFOS过程的功能机制，在一定程度上阐明了PFOA和PFOS低积累生菜品种形成的机理，为揭示植物吸收转运有机污染物微观机制的瓶颈问题奠定基础，并为发展基于有机污染物低积累作物品种的绿色分子育种技术提供理论和技术支撑，对于有效利用大面积中低程度污染土壤开展安全农业生产具有重要的科学意义和现实意义。