背景回顾：Heat stress limits plant growth, development, and crop yield, but how plant cells precisely sense and transduce heat stress signals remains elusive. 

主要发现：Here, we identified a conserved heat stress response mechanism to elucidate how heat stress signal is transmitted from the cytoplasm into the nucleus for epigenetic modifiers. We demonstrate that HISTONE DEACETYLASE 9 (HDA9) transduces heat signals from the cytoplasm to the nucleus to play a positive regulatory role in heat responses in Arabidopsis.

结果1-热诱导的HDA9核积累：Heat specifically induces HDA9 accumulation in the nucleus. Under heat stress, the phosphatase PP2AB′β directly interacts with and dephosphorylates HDA9 to protect HDA9 from 26S proteasome-mediated degradation, leading to the translocation of nonphosphorylated HDA9 to the nucleus. This heat-induced enrichment of HDA9 in the nucleus depends on the nucleoporin HOS1.

结果2-HDA9核中介导植物生长和热响应之间的平衡：In the nucleus, HDA9 binds and deacetylates the target genes related to signaling transduction and plant development to repress gene expression in a transcription factor YIN YANG 1–dependent and –independent manner, resulting in rebalance of plant development and heat response. 

结果3-小麦和水稻等作物中的保守机制：Therefore, we uncover an HDA9-mediated positive regulatory module in the heat shock signal transduction pathway. More important, this cytoplasm-to-nucleus translocation of HDA9 in response to heat stress is conserved in wheat and rice, which confers the mechanism significant implication potential for crop breeding to cope with global climate warming.

 摘 要 

热胁迫限制植物的生长和发育，降低作物产量；但是，植物细胞如何精确感知和转导热胁迫信号仍不清楚。本文中，作者鉴定到了一个保守的热胁迫响应机制，解释了热胁迫信号是如何从胞质转运进核进行表观修饰的。作者发现组蛋白去乙酰化酶HDA9将热信号从胞质转运进核，从而在拟南芥的热胁迫响应中扮演着一个正调控因子的作用。高温会特异性诱导HDA9在核中的积累。在热胁迫下，磷酸酶PP2AB′β直接与HDA9互作，去磷酸化HDA9蛋白，从而避免HDA9蛋白被26S蛋白酶体途径所降解，进而导致非磷酸化的HDA9被转运至核中。这一热诱导的HDA9核富集依赖于核孔蛋白HOS1。在细胞核中，HDA9能够结合并去乙酰化与信号转导和植物发育相关的靶基因，以转录因子YIN YANG 1依赖或非依赖型的方式抑制基因的表达，最终重建植物在发育和热响应之间的平衡。因此，作者揭示了一个HDA9介导的植物热激信号转导通路的正调控模块。更重要的是，HDA9响应热胁迫从胞质转运至核这一过程在小麦和水稻中同样存在，这可能为作物育种以应对全球气候变暖提供了重要机制。

** 郑术芝 **