Engineering Arsenic Tolerance and Hyperaccumulation in Plants for Phytoremediation by a?PvACR3?Transgenic Approach

Yanshan Chen???,?Wenzhong Xu??,?Hongling Shen??,?Huili Yan???,?Wenxiu Xu??,?Zhenyan He??, and?Mi Ma?*?

??University of Chinese Academy of Sciences, Beijing 100049, China

Abstract:

Arsenic (As) pollution is a global problem, and the plant-based cleanup of contaminated soils, called phytoremediation, is therefore of great interest. Recently, transgenic approaches have been designed to develop As phytoremediation technologies. Here, we used a one-gene transgenic approach for As tolerance and accumulation in?Arabidopsis thaliana. PvACR3, a key arsenite [As(III)] antiporter in the As hyperaccumulator fern?Pteris vittata, was expressed in?Arabidopsis, driven by the CaMV 35S promoter. In response to As treatment,PvACR3?transgenic plants showed greatly enhanced tolerance.?PvACR3?transgenic seeds could even germinate and grow in the presence of 80 米M As(III) or 1200 米M arsenate [As(V)] treatments that were lethal to wild-type seeds. PvACR3 localizes to the plasma membrane inArabidopsis?and increases arsenite efflux into external medium in short-term experiments. Arsenic determination showed that PvACR3 substantially reduced As concentrations in roots and simultaneously increased shoot As under 150 米M As(V). When cultivated in As(V)-containing soil (10 ppm As), transgenic plants accumulated approximately 7.5-fold more As in above-ground tissues than wild-type plants. This study provides important insights into the behavior of PvACR3 and the physiology of As metabolism in plants. Our work also provides a simple and practical?PvACR3?transgenic approach for engineering As-tolerant and -hyperaccumulating plants for phytoremediation.