背景回顾：Nucleotide composition is suggested to infer gene functionality and ecological adaptation of species to distinct environments. 

提出问题：However, the underlying biological function of nucleotide composition dictating environmental adaptations is largely unknown. 

结果1-低温区植物显著富集RNA G-四链体：Here, we systematically analyze the nucleotide composition of transcriptomes across 1000 plants (1KP) and their corresponding habitats. Intriguingly, we find that plants growing in cold climates have guanine (G)-enriched transcriptomes, which are prone to forming RNA G-quadruplex structures. 

结果2-低温促进RNA G-四链体的形成：Both immunofluorescence detection and in vivo structure profiling reveal that RNA G-quadruplexformation in plants is globally enhanced in response to cold. 

结果3-RNA G-四链体促进mRNA的稳定性：Cold-responsive RNA G-quadruplexes strongly enhanced mRNA stability, rather than affecting translation. Disruption of individual RNA G-quadruplex promotes mRNA decay in the cold, leading to impaired plant cold response.  

结论：Therefore, we propose that plants adopted RNA G-quadruplex structure as a molecular signature to facilitate their adaptation to the cold during evolution.

Model showing the selective enrichment of RG4 driving plant adaptation to cold climates.

核苷酸组成可以推断基因功能和物种对不同环境的生态适应。但是，决定环境适应性的核苷酸组成的潜在生物学功能还不清楚。本文中，作者系统分析了1KP项目转录组的核苷酸组成，以及相应植物物种的生活习性。有趣的是，作者发现生长在寒冷气候区植物的转录组会明显富集鸟嘌呤，其易于形成RNA G-四链体结构。免疫荧光检测和体内结构图谱均发现植物在响应低温胁迫时，体内的RNA G-四链体结构形成得到加强。低温响应的RNA G-四链体能够极大增强mRNA的稳定性，而不是影响翻译。干扰RNA G-四链体能够促进低温下的mRNA衰减，导致植物低温响应缺陷。因此，作者认为植物在演化过程中采用RNA G-四链体结构来作为一种分子标签，以促进对低温的适应。

** Yiliang Ding **