Posttranscriptional regulation of high-affinity sulfate transporters in Arabidopsis by sulfur nutrition.
High-affinity sulfate transporters SULTR1;1 and SULTR1;2 are expressed at epidermis and cortex of Arabidopsis (Arabidopsis thaliana) roots during sulfur limitation. Here, we report that SULTR1;1 and SULTR1;2 are two essential components of the sulfate uptake system in roots and are regulated at posttranscriptional levels together with the previously reported transcriptional control. Double knockout of SULTR1;1 and SULTR1;2 by T-DNA insertion gene disruption resulted in complete lack of sulfate uptake capacity and severely affected plant growth under low-sulfur conditions. Expression of epitope-tagged proteins SULTR1;1mycHis and SULTR1;2mycHis, under the control of the cauliflower mosaic virus 35S promoter, rescued the uptake of sulfate and the growth of the sultr1;1 sultr1;2 double knockout mutant. The recovery of the double knockout phenotypes was attributable to the posttranscriptional accumulation of sulfate transporter proteins that derive from the epitope-tagged transgenic constructs. Both SULTR1;1mycHis and SUTLR1;2mycHis mRNAs were predominantly found in roots and slightly induced by long-term sulfur limitation. SULTR1;1mycHis and SULTR1;2mycHis proteins were found exclusively in roots, and significantly accumulated by sulfur limitation, correlating with the induction of sulfate uptake activities. In the time course of short-term sulfate starvation treatment, SULTR1;1mycHis and SULTR1;2mycHis proteins were significantly accumulated during the 8- to 72-h period, causing substantial induction of sulfate uptake activities, while their corresponding mRNAs were expressed constantly around the initial levels, except for the transient induction in the first 2 h. This study suggested the importance of root-specific and sulfur deficiency-inducible accumulation of SULTR1;1 and SULTR1;2 sulfate transporter proteins for the acquisition of sulfate from low-sulfur environment.
Yoshimoto
Naoko
N
RIKEN Plant Science Center, Tsurumi-ku, Yokohama 230-0045, Japan.
Inoue
Eri
E
Watanabe-Takahashi
Akiko
A
Saito
Kazuki
K
Takahashi
Hideki
H
D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008969:Molecular Sequence Data; D009154:Mutation; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D013455:Sulfur / Q000378:metabolism* / Q000494:pharmacology; D013997:Time Factors; D014158:Transcription, Genetic
D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; C455459:Sultr1;1 protein, Arabidopsis; C455460:Sultr1;2 protein, Arabidopsis; D013455:Sulfur