Contributes to Arsenate Uptake and Transport in Rice.

Arsenic (As) is toxic to organisms, and elevated As accumulation in rice () grain may pose a significant health risk to humans. The predominant form of As in soil under aerobic conditions is As(V), which has a chemical structure similar to that of PO. Rice roots take up As(V) by phosphate (Pi) transporters, such as OsPT1 and OsPT8. In the present study, we investigated the contribution of , belonging to the Pht1 family, on rice As(V) uptake and transport. We determined the mRNA amounts of s in rice seedlings, and expressions of , , and were up-regulated under As(V) conditions. -overexpressing plants were obtained to examine the As (V) transport activity of in rice. When transgenic rice grew in hydroponic culture with 25 and 50 μM As(V), the plants showed sensitivity to As(V) stress with aboveground parts showing delayed growth and the roots stunted. The CRISPR lines showed the opposite phenotype. When plants were grown in 5 μM As(V) solution for 7 days, the As accumulation of -overexpressing plants increased up to twice in roots and shoots. Furthermore, the arsenate uptake rates of -overexpressing lines were higher compared with wild type. The of As(V) uptake in -overexpressing plants increased 23-45% compared with Nipponbare. In the flooded soil, the As accumulation of OsPT4-overexpressing plants increased 40-66% and 22-30% in straw and grain, respectively. While in -cr plants As accumulation in roots decreased 17-30% compared with Nipponbare. Therefore, the present study indicates that is involved in As(V) uptake and transport and could be a good candidate gene to generate low As-accumulating rice.