WRKY6 Transcription Factor Restricts Arsenate Uptake and Transposon Activation in Arabidopsis

Abstract

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Stress constantly challenges plant adaptation to the environment. Of all stress types, arsenic was a major threat during theearly evolution of plants. The most prevalent chemical form of arsenic is arsenate, whose similarity to phosphate renders iteasily incorporated into cells via the phosphate transporters. Here, we found that arsenate stress provokes a notable transposonburst in plants, in coordination with arsenate/phosphate transporter repression, which immediately restricts arsenate uptake. Thisrepression was accompanied by delocalization of the phosphate transporter from the plasma membrane. When arsenate wasremoved, the system rapidly restored transcriptional expression and membrane localization of the transporter. We identify WRKY6as an arsenate-responsive transcription factor that mediates arsenate/phosphate transporter gene expression and restrictsarsenate-induced transposon activation. Plants therefore have a dual WRKY-dependent signaling mechanism that modulatesarsenate uptake and transposon expression, providing a coordinated strategy for arsenate tolerance and transposon genesilencing.