A rice glutaredoxin regulate the expression of aquaporin genes and modulate root responses to provide arsenic tolerance.

Abstract

Rice is the most consumed food crop and essential determinant in global food security program. Currently, arsenic (As) accumulation in rice is a critical concern in terms of both crop productivity and grain quality; therefore, it is an urgent need to reduce As accumulation. Here, we selected a glutaredoxin (OsGrx_C7) gene that plays an essential role in AsIII tolerance in rice. To explore the mechanism, we raised OsGrx_C7 overexpression (OE) rice lines, which showed improved plant AsIII tolerance and lowered its accumulation in grains. Arsenic accumulation in husk, unpolished, and polished rice reduced by ca. 65%, 67%, and 85%, respectively, in OE lines, compared to wild-type (WT) plants. To know the rationale, expression of AsIII transporters (aquaporins) in root and shoot tissues were examined, and revealed that OsGrx_C7 regulates the expression of these genes, which ultimately reduces root to shoot AsIII translocation. Additionally, OsGrx_C7 improves root growth by regulating the expression of oxidative stress-induced root expansion related genes, promote root growth and plant health. Overall, current study suggested that AsIII induced OsGrx_C7 markedly enhanced tolerance to AsIII with reduced accumulation in grains by regulating root expansion and controlling root to shoot As transport by altered expression of AsIII aquaporins.