Nat Commun.∣中科院逆境中心發現與葉片衰老和局部氣候適應性相關的表觀遺傳等位基因

2018年1月31日nature communications在線發表了題為「A naturally occurring epiallele associates with leaf senescence and local climate adaptation in Arabidopsis accessions」的文章。

本文由中國科學院上海植物逆境生物學研究中心朱健康課題組完成。文章發現了一個新的表觀遺傳等位基因，其甲基化狀態可以穩定遺傳，並與葉片衰老和局部氣候適應性相關。

摘要：

表觀遺傳變異可以促進對變化環境的適應，但是缺乏天然的表觀遺傳等位基因對適應性進化貢獻的證據。在這裡，我們鑒定了一個名為「NMR19」（天然存在的DNA甲基化變異區域19）的反轉錄轉座子，其在擬南芥不同種質的甲基化和基因組的位置不同。根據NMR19-4和NMR19-16的位置，我們將它們歸類為NMR19，並發現NMR19-4是一個表觀遺傳的等位基因，可以通過調節PPH的表達來調控葉片衰老。我們發現NMR19-4的DNA甲基化狀態是穩定遺傳的，與遺傳變異無關。另外，進一步分析表明，NMR19-4的DNA甲基化與局部氣候相關，這意味著NMR19-4是與環境相關的表觀遺傳等位基因。總結起來，我們發現了一個新的表觀遺傳等位基因，並為其在適應局部氣候方面的起源和潛在功能提供了機制性的見解。

Abstract：

Epigenetic variation has been proposed to facilitate adaptation to changing environments, but evidence that natural epialleles contribute to adaptive evolution has been lacking. Here we identify a retrotransposon, named 「NMR19」 (naturally occurring DNA methylation variation region 19), whose methylation and genomic location vary among Arabidopsis thaliana accessions. We classify NMR19 as NMR19-4 and NMR19-16 based on its location, and uncover NMR19-4 as an epiallele that controls leaf senescence by regulating the expression of PHEOPHYTIN PHEOPHORBIDE HYDROLASE (PPH). We find that the DNA methylation status of NMR19-4 is stably inherited and independent of genetic variation. In addition, further analysis indicates that DNA methylation of NMR19-4 correlates with local climates, implying that NMR19-4 is an environmentally associated epiallele. In summary, we discover a novel epiallele, and provide mechanistic insights into its origin and potential function in local climate adaptation.

Fig. 6 NMR19-4m controls leaf senescence