Abstract
SULTR1;2 high-affinity sulfate transporter facilitates sulfate uptake from the environment. In Arabidopsis, expression of SULTR1;2 was induced upon sulfur deficiency (-S), which enables the plants to survive under -S condition. The -S response of SULTR1;2 is controlled by SLIM1 transcription factor. Previously, we have identified cis-acting element involved in the -S-inducible expression of SULTR1;2, which contains WRKY binding sequence. In this study, we have tried to identify the WRKY transcription factors that control -S-inducible expression of SULTR1;2. Among the 72 members of WRKY transcription factor in Arabidopsis, 3 members exhibited the up-regulated transcript levels by -S in the wild type plants but not in slim1 mutant. Then we isolated T-DNA insertion mutants of 3 WRKY members, and analyzed SULTR1;2 expression and sulfate uptake activity. Both were significantly down-regulated under -S condition in these mutants comparing with wild-type plants, suggesting the involvement of these WRKY transcription factors in -S-inducible expression of SULTR1;2 and sulfate uptake.
