The transcription factor WRKY12 negatively regulates iron entry into seeds in Arabidopsis.

YSL1 and YSL3 transport metal-Nicotianamine (NA) complexes to leaves, pollen and developing seeds and play an important role in regulating the iron (Fe) accumulation during seed development and maturation stages; however, how their transcriptional levels are regulated remains unknown. In this study, we used yeast one hybrid screening to identify a transcription factor WRKY12 that directly regulates the transcription levels of YSL1 and YSL3 genes. WRKY12 has opposite expression patterns to YSL1 and YSL3. The wrky12 mutants are tolerant to Fe deficiency, whereas the WRKY12-overexpression lines are sensitive to Fe deficiency. During the development and maturation of seeds, WRKY12 can directly bind to the promoters of YSL1 and YSL3 and inhibit their expression. Genetic analysis showed that WRKY12 functions upstream of YSL1 and YSL3 in the Fe intake during seed development and maturation stages. Together, our results suggest that WRKY12 negatively regulates the iron intake in plant seeds by inhibiting the expression of YSL1 and YSL3.