Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Cientificas, Campus de Cantoblanco, 28049 Madrid, Spain.
Plant Cell. 2013 Aug;25(8):2944-57. doi: 10.1105/tpc.113.114009. Epub 2013 Aug 6.
Stress constantly challenges plant adaptation to the environment. Of all stress types, arsenic was a major threat during the early evolution of plants. The most prevalent chemical form of arsenic is arsenate, whose similarity to phosphate renders it easily incorporated into cells via the phosphate transporters. Here, we found that arsenate stress provokes a notable transposon burst in plants, in coordination with arsenate/phosphate transporter repression, which immediately restricts arsenate uptake. This repression was accompanied by delocalization of the phosphate transporter from the plasma membrane. When arsenate was removed, the system rapidly restored transcriptional expression and membrane localization of the transporter. We identify WRKY6 as an arsenate-responsive transcription factor that mediates arsenate/phosphate transporter gene expression and restricts arsenate-induced transposon activation. Plants therefore have a dual WRKY-dependent signaling mechanism that modulates arsenate uptake and transposon expression, providing a coordinated strategy for arsenate tolerance and transposon gene silencing.
压力不断挑战着植物对环境的适应。在所有的压力类型中，砷在植物的早期进化过程中是一个主要的威胁。砷最常见的化学形式是砷酸盐，其与磷酸盐的相似性使其能够通过磷酸盐转运体轻易地进入细胞。在这里，我们发现砷酸盐胁迫会引发植物中转座子的明显爆发，与砷酸盐/磷酸盐转运体的抑制相协调，这立即限制了砷酸盐的摄取。这种抑制伴随着磷酸盐转运体从质膜的定位改变。当去除砷酸盐时，该系统会迅速恢复转运体的转录表达和膜定位。我们确定 WRKY6 是一种砷酸盐响应的转录因子，它介导砷酸盐/磷酸盐转运体基因的表达，并限制砷酸盐诱导的转座子激活。因此，植物具有双 WRKY 依赖性信号机制，调节砷酸盐的摄取和转座子的表达，为砷酸盐耐受和转座子基因沉默提供了协调的策略。
