Phosphate deficiency signaling pathway is a target of arsenate and phosphate transporterOsPT1is involved in As accumulation in shoots of rice

Abstract

Arsenate [As(V)] is toxic to organisms, and phosphate (Pi) transporter can mediate As(V) uptake due to their similarity in chemical structure. In the rice (Oriza sativa L.) genome, 13 Pi transporter genes (OsPTs) are present. Their response to As(V) and contribution to As(V) accumulation are unknown. We determined absolute mRNA amount of OsPTs in rice seedlings and OsPT1, OsPT2, OsPT4, and OsPT8 were quantified by real-time polymerase chain reaction (PCR). OsPT2, OsPT4, and OsPT8 were highly induced by Pi deficiency, while OsPT1 was not. In accordance with Pi deficiency response, OsPT2, OsPT4, and OsPT8 induction by Pi deficiency were severely suppressed by As(V). Those data suggest that As(V) affects Pi deficiency signaling in rice. To examine the As(V) transport activity of OsPT1 in planta, we obtained T-DNA mutant of OsPT1 (ospt1). The transcript expression level of OsPT1 in ospt1 was reduced by 70% in shoots and 50% in roots compared to those in the wild-type (WT), and arsenic (As) concentrations in shoots were reduced by 60% compared to WT. We further overexpressed OsPT1-GFP in rice. Overexpression lines showed higher As accumulation in shoots compared to wild-type. OsPT1-GFP is localized to plasma membrane. These results indicate that OsPT1 is involved in As(V) uptake from soil or apoplast.

Decreasing arsenic accumulation in rice by overexpressing OsNIP1;1 and OsNIP3;3 through disrupting arsenite radial transport in roots

“…In contrast to As(III), As(V) is present as a dissociated oxyanion under normal pH conditions. As(V) is a chemical analog of phosphate and is taken up by phosphate transporters (PTs), such as OsPT1, OsPT4 and OsPT8 in rice (Kamiya et al, 2013;Wang et al, 2016;Cao et al, 2017;Ye et al, 2017). Inside root cells, As(V) is readily reduced to As(III) by As(V) reductases including OsHAC1;1, OsHAC1;2 and OsHAC4 (HAC, High Arsenic Content) (Shi et al, 2016;Xu et al, 2017).…”

Arsenic Accumulation in Rice and Probable Mitigation Approaches: A Review

“…The phosphate transporter gene family of rice includes 13 OsPT genes encoding the transporters range from OsPT1to OsPT13 [39]. Among them, the roles of OsPT1 and OSPT8 in arsenic transport have been investigated in details by Kamiya et al [40] and Wang et al [41], respectively. OsPT1 mediates arsenate transport from root to shoot [40].…”

“…Among them, the roles of OsPT1 and OSPT8 in arsenic transport have been investigated in details by Kamiya et al [40] and Wang et al [41], respectively. OsPT1 mediates arsenate transport from root to shoot [40]. Whereas, OsPT8 is a key transporter protein for arsenate uptake into rice roots, and a profound toxic effect on root elongation was exerted after arsenate uptake mediated by OsPT8 [41].…”

Involvement of phosphate supplies in different transcriptional regulation pathway of Oryza sativa L.’s antioxidative system in response to arsenite and cadmium stress

“…Phosphorus is a component of key molecules such as nucleic acids, phospholipids and ATP; it plays a role in controlling key enzymatic reactions and thus influences the regulation of metabolic pathways (Blank 2012;Kamiya et al 2013). The competitive effects of phosphate has been expressed that arsenate toxicity is antagonistically reduced by phosphate addition (Liu et al 2004), whereas such a relation seems to be obscure between arsenite and phosphate.…”