背景回顾：Vernalization is a physiological process of which the prolonged cold exposure establishes flowering competence in winter plants. In hexaploid wheat, TaVRN1 is a cold-induced key regulator that accelerates floral transition. 

提出问题：However, the molecular mechanism underlying the gradual activation of TaVRN1 during vernalization process still remains unknown.

主要发现：Here we identified a novel transcript VAS (TaVRN1 alternative splicing) as a non-coding RNA derived from the sense of VRN1 gene only in winter wheat, which regulated VRN1 transcription for flowering. 

结果1-VAS表达模式和过表达表型：The data showed that VAS was induced during the early period of vernalization, and over-expression of VAS promoted VRN1 expression to accelerate flowering in winter wheat.

结果2-VAS下游TaRF2b： VAS physically associates with TaRF2b and facilitates TaRF2b-TaRF2a complex docking at TaVRN1 promoter during the middle period of vernalization. 

结果3-TaRF2b功能鉴定：TaRF2b recognizes the Sp1 motif within TaVRN1 proximal promoter region, which was gradually exposed along with the disruption of a loop structure at TaVRN1 locus during vernalization, to activate the transcription of TaVRN1. tarf2b mutants delayed flowering, but over-expression lines showed earlier flowering. 

结论：Thus, our data revealed a distinct regulatory mechanism of a long non-coding RNA by which facilitates the transcription factor targeting to regulate wheat flowering, providing a novel insight in understanding the vernalization molecular process and a potential for crop genetic improvement in wheat.

 摘 要 

春化是一种生理过程，在该过程中冬季植物长时间暴露在低温环境下，从而建立起开花能力。在六倍体小麦中，TaVRN1基因是冷诱导关键调控子，能够加速小麦的成花转变。但是，在春化过程中的TaVRN1基因的逐步激活潜在分子调控机制仍然不清楚。本文中，作者鉴定到了TaVRN1基因一个新的可变剪切转录本VAS，该转录本作为一个非编码的RNA，源自于VRN1基因的反义链，仅在冬小麦种存在，并且通过调控VRN1基因的表达，从而促进开花。实验数据表明，VAS在春化早期被诱导表达，并且过表达VAS会促进VRN1的表达，促进冬小麦的开花。在春化中期，VAS与TaRF2b发生互作，促进TaRF2b-TaRF2a复合体结合在TaVRN1基因启动子上。TaRF2b识别TaVRN1近启动子区域上的Sp1基序，而该区域在春化过程中随着TaVRN1位点上环结构破坏而逐渐暴露，从而激活TaVRN1的转录。tarf2b突变体开花延迟，但过表达株系表现出开花提前。因此，本文的数据揭示了一个长链非编码RNA的独特调控机制，其通过促进靶向转录因子调控小麦开花，为理解小麦春化的分子进程和作物遗传改良提供了新的视角。