提出问题：While organisms cope with the former by the well-characterized mechanism of the circadian clock, there is limited information on the molecular mechanisms underlying long-term responses to the latter.

研究对象：Histone H3 lysine 27 trimethylation (H3K27me3), a repressive histone modification, imparts stability and plasticity to gene regulation during developmental transitions.

主要研究：Here we studied the seasonal and diel dynamics of H3K27me3 at the genome-wide level in a natural population of perennial Arabidopsis halleri and compared these dynamics with those of histone H3 lysine 4 trimethylation (H3K4me3), an active histone modification.

结果：Chromatin immunoprecipitation sequencing revealed that H3K27me3 exhibits seasonal plasticity and diel stability. Furthermore, we found that the seasonal H3K27me3 oscillation is delayed in phase relative to the H3K4me3 oscillation

结论：Our findings suggest that H3K27me3 monitors past transcriptional activity to create long-term gene expression trends during organismal responses over weeks in natural fluctuating environments.

p.s. 相对于生物钟控制的昼夜节律在植物中研究得已经很多了，但是植物对于季节性的环境变化是如何响应的这一块研究得还比较少，去年该通讯也发表了一篇NP，对鼠耳芥连续两年每周取样，同时在四个分至点连续两天每两个小时取样，研究了鼠耳芥叶片转录组的季节性响应，详情见链接：Nature Plants:植物适应自然环境季节性改变的转录组动态变化。