Arsenic hyperaccumulation in Pteris vittata: A critical review on mechanisms of rhizospheric mobilization, xylem transport and cellular detoxification.

Arsenic (As) is carcinogenic toxicity and widespread in soils due to intensive arsenical pesticide application and industrial activities. Pteris vittata (P. vittata) is the first reported As hyperaccumulator. Phytoremediation efficiency of As-contaminated soils using P. vittata depends on rhizosphere As mobilization, root-to-shoot translocation (uptake and redox), and detoxification (methylation and compartmentalization) efficiencies. Therefore, a better understanding of how P. vittata tolerates and hyperaccumulates As helps to improve the remediation efficiency and practical application. The aims of this review are to: (1) discuss influencing factors and mechanisms of P. vittata and rhizobacteria (As resistance, mobilization, AsIII oxidization, and AsV reduction) in mediating soil As mobilization; (2) clarify the processes and roles of transporters (PvPht1;1, PvPht1;2, PvPht1;3, PvTIP4;1, PvACR2, PvACR3, PvACR3;1, PvACR3;2, PvACR3;3, PvHAC1, PvAsE1, PvHAC2, PvTPI, and PvGRX5) in As (AsV, AsIII, DMA, and MMA) uptake, translocation, accumulation and distribution; and (3) identify the roles of critical genes (PvPht2;1, PvGAPC1, PvOCT4, and PvGSTF1) in As tolerance and detoxification. In addition, current knowledge gaps and future research perspectives are proposed. The information will help to better understand the translocation pathways and physiological and molecular mechanisms for As tolerance and hyperaccumulation by P. vittata, thereby strategizing how to efficiently remediate As-polluted environments using the hyperaccumulating plants or developing genetic plants.