背景回顾：Photoperiod responsiveness is a key factor limiting the geographic distribution of cultivated soybean and its wild ancestor. 

提出问题：In particular, the genetic basis of the adaptation in wild soybean remains poorly understood.

主要发现：Here, we identified the novel locus Time of Flowering 5 (Tof5), which promotes flowering and enhances adaptation to high latitudes in both wild and cultivated soybean, and determined that it encodes a homologue of Arabidopsis thaliana FRUITFULL (FUL). 

结果1-平衡选择：Importantly, we suggest that different alleles of Tof5 have undergone parallel selection. The Tof5H1 allele was strongly selected by humans after the early domestication of cultivated soybean, while Tof5H2 allele was naturally selected in wild soybean, and in each case facilitating adaptation to high latitudes. 

结果2-上游调控因子：The key flowering repressor E1 suppress the transcription of Tof5 by binding to its promoter. 

结果3-下游靶基因：In turn, Tof5 physically associate with the promoters of two important FLOWERING LOCUS T (FT), FT2a and FT5a, to upregulate their transcription and promote flowering under long photoperiods. 

结论：Our findings provide insight into how wild soybean adapted to high latitudes through natural selection, and indicate that cultivated soybean underwent changes in the same gene but involving a distinct allele that was artificially selected after domestication.

 摘 要 

光周期响应是限制栽培种大豆及其野生祖先种地理分布的关键因素。目前，野生大豆适应性演化的遗传基础还不清楚。本文中，作者鉴定到了一个新的基因位点Tof5，该基因在野生种和栽培种大豆中均能够促进开花，增强对高纬度的适应，作者还发现Tof5基因是拟南芥FUL基因的同源基因。重要的是，作者发现不同的Tof5等位基因经历了平衡选择。其中，栽培种大豆的Tof5H1等位基因在早期驯化过程中，受到了人类的强选择；而野生大豆的Tof5H2等位基因则受到了自然选择，并且两种情况下均促进了各自群体对于高纬度的适应性。关键开花抑制子E1通过结合到Tof5的启动子，抑制Tof5的表达。转而，Tof5能够与大豆的FT2a和FT5a基因的启动子物理互作，在长日照条件下促进这两个基因的转录，促进开花。本文的研究结果揭示了野生大豆是如何通过自然选择适应高纬度地区，并且发现了栽培种大豆在驯化过程中受到人工选择、适应高纬度的基因是同一个基因，但是等位基因并不一致。

 通讯作者 

** 孔凡江 **