背景回顾：Flowering plants (angiosperms) can grow at extreme altitudes, and have been observed growing as high as 6,400 metres above sea level; however, the molecular mechanisms that enable plant adaptation specifically to altitude are unknown. One distinguishing feature of increasing altitude is a reduction in the partial pressure of oxygen (pO2). 

主要发现：Here we investigated the relationship between altitude and oxygen sensing in relation to chlorophyll biosynthesis—which requires molecular oxygen—and hypoxia-related gene expression. 

结果1-大气氧浓度与原叶绿素酯的关联：We show that in etiolated seedlings of angiosperm species, steady-state levels of the phototoxic chlorophyll precursor protochlorophyllide are influenced by sensing of atmospheric oxygen concentration. 

结果2-ERFVII-FLU模块：In Arabidopsis thaliana, this is mediated by the PLANT CYSTEINE OXIDASE (PCO) N-degron pathway substrates GROUP VII ETHYLENE RESPONSE FACTOR transcription factors (ERFVIIs). ERFVIIs positively regulate expression of FLUORESCENT IN BLUE LIGHT (FLU), which represses the first committed step of chlorophyll biosynthesis, forming an inactivation complex with tetrapyrrole synthesis enzymes that are negatively regulated by ERFVIIs, thereby suppressing protochlorophyllide. 

结果3-自然群体：In natural populations representing diverse angiosperm clades, we find oxygen-dependent altitudinal clines for steady-state levels of protochlorophyllide, expression of inactivation complex components and hypoxia-related genes. Finally, A. thaliana accessions from contrasting altitudes display altitude-dependent ERFVII activity and accumulation. 

结论：We thus identify a mechanism for genetic adaptation to absolute altitude through alteration of the sensitivity of the oxygen-sensing system.

 摘 要 

有花植物（又称被子植物）能够在极端海拔高度生长，最高能够在海拔6400米的地区生长；但是，植物适应高海拔的分子机制还不清楚。随着海拔升高，其中一个比较显著的特征就是氧分压的降低。本文中，作者研究了海拔与氧气感知在需要分子氧的叶绿素生物合成中的关联，以及低氧相关基因的表达。作者发现在被子植物的黄化苗中，受光损伤的叶绿素前提原叶绿素酯的稳态水平受到大气氧浓度感应的影响。在拟南芥中，该过程是由PCO N-degron途径的底物ERFVIIs转录因子所介导的。ERFVIIs能够正调控FLU基因的表达，而后者能够抑制叶绿素生物合成的第一步，与被ERFVIIs负调控的四吡咯合成酶形成了一个失活复合体，从而抑制原叶绿素酯。在能够代表被子植物不同类群物种的自然群体中，作者发现原叶绿素酯的稳态水平、失活复合体组分和低氧相关基因的表达都存在氧依赖型的海拔梯度。最终，来自于不同海拔高度的拟南芥材料表现出与海拔高度相关的ERFVII蛋白活性和积累。因此，作者在本文中鉴定到了一个通过改变氧感应系统的敏感性，来促进植物适应高海拔的遗传机制。

 Michael J. Holdsworth