HvFT3 & HvOS2: How could winter barley flower with little or no cold?

Abstract

Winter barleys need to have completed a period of cold (vernalization) before the day is long enough to promote flowering, which is regulated by the interactions between the activators HvVRN1 and HvFT1 and the repressor HvVRN2 (Fig.1). The promoter under short days, HvFT3, has an adaptive role in Mediterranean conditions in winter plants that have not satisfied their vernalization requirement 1 . HvOS2, ortholog of FLC, is a flowering repressor also downregulated by vernalization in barley2 . In this study, we characterize the role of HvFT3 and HvOS2 as possible players in the flowering pathway under incomplete or null vernalization. We provide new information on the complex mechanism of flowering in suboptimal conditions. As rising winter temperatures will reduce vernalization potential in many regions, winter cultivars will have to be adjusted to new conditions. HvFT3 and HvOS2 could have a role in adaptation to non-inductive conditions for winter barley, and in the development of new ideotypes for future climatic conditions.