Abstract
Sulfate transporter gene family of Arabidopsis is consisted of 14 isoforms classified into 5 groups. In this study, we demonstrated that transgenic plants expressing GFP fusion protein of SULTR2;1 and SULTR3;5 showed specific expression in the root pericycle and the xylem parenchyma cells. When expressed in yeast mutant lacking sulfate transporters, SULTR2;1 indicated low-capacity sulfate uptake, and SULTR3;5 exhibited little sulfate transport activity. Interestingly, co-expression of SULTR2;1 and SULTR3;5 showed 2-3 times higher sulfate uptake than that of SULTR2;1 alone suggesting SULTR3;5 has a strong potential to mediate sulfate transport. To analyze the function of these transporters, we measured root-to-shoot transport of sulfate using knockout plants. In the knockouts, translocation of sulfate to shoot was restricted compared to the wild-type under sulfate deficient condition where transcript of SULTR2;1 is abundantly accumulated. These results suggest that both SULTR2;1 and SULTR3;5 function for sulfate transport in the vasculature.
