Abstract
Low-affinity sulfate transporter SULTR2;1 has been considered to function in sulfate translocation from roots to shoots because of its predominant localization in vascular tissues. The mRNA level of SULTR2;1 is highly up-regulated responding to sulfate starvation (-S) in roots but decreased in shoots. In this study, we identified the -S-responsive region of SULTR2;1 and found that -S-responsive expression of SULTR2;1 in roots requires the 3'non-transcribed region. In transgenic plants containing the SULTR2;1-5'region::GFP::SULTR2;1-3'region fusion construct, GFP accumulation was induced by -S not only in vascular tissues but in cortex. Physiological relevance of this 3'region was verified in plants containing T-DNA insertions in SULTR2;1-3'region (tKO). The -S response of SULTR2;1 was completely abolished in roots while unaffected in shoots by tKO. In addition, both the sulfate uptake and translocation were decreased in tKO under -S condition, suggesting that SULTR2;1 contributes to both processes through its induction driven by the 3'region in roots.
