本论文于2017年2月发表于Plant Physiology，原文题目如下：

A Flowering Locus C Homolog Is a Vernalization-Regulated Repressor in Brachypodium and Is Cold Regulated in Wheat

冬季谷物需要长时间的寒冷才能从营养过渡到生殖发育，这个过程称为春化，在拟南芥中已被广泛研究。在拟南芥中，一个称为FLC 的关键开花抑制子定量控制春化要求。相反，在谷类中，春化反应主要由VERNALIZATION基因VRN1和VRN2调控。在这里，我们表征了一种新近发现的单子叶植物FLC直系同源物ODDSOC2，它属于FLC谱系。通过研究它在不同种类短柄草种质中的表达，我们发现它是春化要求的一个很好的预测指标。转基因的分析表明，BdODDSOC2是一个春化调控开花抑制子。在大多数短柄草种质中，BdODDSOC2受冷下调，并且其中一个冬季种质受冷明显下调。对冷的响应中，BdODDSOC2先于BdVRN1。当稳定下调时，该机制与在BdODDSOC2染色质上H3K27me3修饰有关。最后，同系物特异性基因表达分析将TaAGL33及其剪接变体TaAGL22鉴定为小麦中FLC直系同源物，其行为与短柄草 ODDSOC2最相似。总体而言，我们的研究表明，ODDSOC2不仅在真核生物中与FLC有系统发生关系，而且在短柄草和其他温带草的春化途径中也可以作为开花抑制物。这些见解可能有助于在育种中完善温带谷类的春化要求，并使不同品种适应变化的气候。

Winter cereals require prolonged cold to transition from vegetative to reproductive development. This process, referred to as vernalization, has been extensively studied in Arabidopsis (Arabidopsis thaliana). In Arabidopsis, a key flowering repressor called FLOWERING LOCUS C (FLC) quantitatively controls the vernalization requirement. By contrast, in cereals, the vernalization response is mainly regulated by the VERNALIZATION genes, VRN1 and VRN2. Here, we characterize ODDSOC2, a recently identified FLC ortholog in monocots, knowing that it belongs to the FLC lineage. By studying its expression in a diverse set of Brachypodium accessions, we find that it is a good predictor of the vernalization requirement. Analyses of transgenics demonstrated that BdODDSOC2 functions as a vernalization-regulated flowering repressor. In most Brachypodium accessions BdODDSOC2 is down-regulated by cold, and in one of the winter accessions in which this down-regulation was evident, BdODDSOC2 responded to cold before BdVRN1. When stably down-regulated, the mechanism is associated with spreading H3K27me3 modifications at the BdODDSOC2 chromatin. Finally, homoeolog-specific gene expression analyses identify TaAGL33 and its splice variant TaAGL22 as the FLC orthologs in wheat (Triticum aestivum) behaving most similar to Brachypodium ODDSOC2. Overall, our study suggests that ODDSOC2 is not only phylogenetically related to FLC in eudicots but also functions as a flowering repressor in the vernalization pathway of Brachypodium and likely other temperate grasses. These insights could prove useful in breeding efforts to refine the vernalization requirement of temperate cereals and adapt varieties to changing climates.

每日一词

Brachypodium

短柄草属; 短柄草;