记者日前从中国科学院植物研究所获悉，该所研究员华学军研究组与研究员金京波研究组合作，针对植物盐胁迫“记忆”的调控机制展开了研究，相关论文在线发表在《美国科学院院刊（Proceedings of the National Academy of Sciences of the United States of America）》杂志上。

研究人员发现，拟南芥对盐胁迫诱导的脯氨酸积累及脯氨酸合成的关键酶基因P5CS1转录表达具有“记忆”能力，并且这种“记忆”依赖于胁迫恢复阶段的光照以及由植物光形态建成调控因子HY5所介导的光信号通路。这一研究结果揭示了调控植物胁迫“记忆”的新机制。

据了解，为适应复杂多变的环境，植物能够对经历过的不利环境刺激产生一定的“记忆”，从而有利于更快更强地应对再次出现的胁迫。然而，人们对植物的胁迫“记忆”是否受其他环境因素的调节还知之甚少。（来源：科学网 丁佳）

Light affects salt stress-induced transcriptional memory of P5CS1 in Arabidopsis

Abstract  To cope with environmental stresses, plants often adopt a memory response upon primary stress exposure to facilitate a quicker and stronger reaction to recurring stresses. However, it remains unknown whether light is involved in the manifestation of stress memory. Proline accumulation is a striking metabolic adaptation of higher plants during various environmental stresses. Here we show that salinity-induced proline accumulation is memorable and HY5-dependent light signaling is required for such a memory response. Primary salt stress induced the expression of Δ1-pyrroline-5-carboxylate synthetase 1 (P5CS1), encoding a proline biosynthetic enzyme and proline accumulation, which were reduced to basal level during the recovery stage. Reoccurring salt stress-induced stronger P5CS1 expression and proline accumulation were dependent upon light exposure during the recovery stage. Further studies demonstrated that salt-induced transcriptional memory of P5CS1 is associated with the retention of increased H3K4me3 level at P5CS1 during the recovery stage. HY5 binds directly to light-responsive element, C/A-box, in the P5CS1 promoter. Deletion of the C/A-box or hy5 hyh mutations caused rapid reduction of H3K4me3 level at P5CS1 during the recovery stage, resulting in impairment of the stress memory response. These results unveil a previously unrecognized mechanism whereby light regulates salt-induced transcriptional memory via the function of HY5 in maintaining H3K4me3 level at the memory gene.

原文链接：http://www.pnas.org/content/113/51/E8335.full