Overexpression of the phosphate transporter gene OsPT8 improves the Pi and selenium contents in Nicotiana tabacum

Abstract

Selenite is the predominant form of selenium (Se) available to plants in soils. Recent studies have suggested that selenite uptake is probably mediated by Pi transporters. Research on the molecular mechanism of Pi and Se uptake by plants is important for the development of Se-enriched agricultural products. In this study, we report the function of a Pi transporter, OsPT8, which was not only involved in Pi uptake but also in Se uptake in tobacco. Overexpression of OsPT8 in tobacco significantly increased the total P concentration under Pi-sufficient conditions, and the biomass of OsPT8-Oe lines was higher than that of the wild type under Pi-deficient conditions. OsPT8 overexpression not only increased the Pi concentration, but also resulted in greater Se accumulation in transgenic tobacco compared with the wild type under a high Pi concentration. Expression analysis showed that the Pi transporter genes NtPT1 and NtPT2 were strongly upregulated in transgenic tobacco under high Pi conditions. Together, these results suggest that Pi and Se uptake and translocation by the Pi transporter OsPT8 might function in a complex combinational way in tobacco, and that OsPT8 might be a potential candidate gene for breeding Se-enriched tobacco.