背景回顾：In plants, the shoot apical meristem (SAM) is essential for the growth of above-ground organs. 

提出问题：However, little is known about its molecular responses to abiotic stresses.

主要发现：Here, we show that the SAM of Arabidopsis thaliana displays an autonomous heat stress (HS) memory of a previous non-lethal HS, allowing the SAM to regain growth after exposure to an otherwise lethal HS several days later. 

结果1-利用RNA-seq鉴定关键基因：Using RNA-seq, we identified genes participating in establishing the SAM’s HS transcriptional memory including the stem cell (SC) regulators CLAVATA1(CLV1) and CLV3, HEAT SHOCK PROTEIN 17.6A (HSP17.6A), and primary carbohydrate metabolism gene FRUCTOSE-BISPHOSPHATE ALDOLASE 6 (FBA6). 

结果2-功能基因及上游调控基因鉴定：We demonstrate that sugar availability is essential for survival of plants at high temperature. HEAT SHOCK TRANSCRIPTION FACTOR A2 (HSFA2A) directly regulates expression of HSP17.6A and FBA6 by binding to heat shock elements in their promoters, demonstrating that HSFA2 is required for a transcriptional activation of SAM memory genes. 

结论：Collectively, plants have evolved a sophisticated protection mechanism to maintain SC and, hence, their capacity to re-initiate shoot growth after stress release.

 摘 要 

在植物中，茎尖分生组织（SAM）对于地上部分器官的生长是必需的。但是，我们对于非生物胁迫下的SAM响应仍所知甚少。本文中，作者发现拟南芥的SAM对非致死高温胁迫预处理存在自主性高温胁迫记忆，使得SAM能够在隔一段时间后再次暴露在高温胁迫下仍能够继续生长。利用RNA测序，作者鉴定了很多参与SAM高温胁迫转录记忆相关的基因，比如干细胞调控子CLV1和CLV3、热激蛋白编码基因HSP17.6A以及果糖-1,6-二磷酸醛缩酶编码基因FBA6。作者发现可以利用糖含量对于高温胁迫下植物的存活是必需的。另外，热激转录因子HSFA2A通过直接结合到HSP17.6A和FBA6基因启动子区的热激元件上，直接调控这两个基因的表达，说明HSFA2作用于SAM高温胁迫记忆相关基因的转录激活。综上，本文的研究揭示了植物演化出了一个精细的保护机制，使得植物在逆境下能够维持干细胞，从而得以在胁迫之后恢复生长。