Ream T S, Woods D P, Amasino R M
Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
Cold Spring Harb Symp Quant Biol. 2012;77:105-15. doi: 10.1101/sqb.2013.77.014449. Epub 2013 Apr 25.
Timing of flowering is key to the reproductive success of many plants. In temperate climates, flowering is often coordinated with seasonal environmental cues such as temperature and photoperiod. Vernalization, the process by which a prolonged exposure to the cold of winter results in competence to flower during the following spring, is an example of the influence of temperature on the timing of flowering. In different groups of plants, there are distinct genes involved in vernalization, indicating that vernalization systems evolved independently in different plant groups. The convergent evolution of vernalization systems is not surprising given that angiosperm families had begun to diverge in warmer paleoclimates in which a vernalization response was not advantageous. Here, we review what is known of the vernalization response in three different plant groups: crucifers (Arabidopsis), Amaranthaceae (sugar beet), and Pooideae (wheat, barley, and Brachypodium distachyon). We also discuss the advantages of using Brachypodium as a model system to study flowering and vernalization in the Pooids. Finally, we discuss the evolution and function of the Ghd7/VRN2 gene family in grasses.
开花时间对于许多植物的繁殖成功至关重要。在温带气候中，开花通常与季节性环境线索如温度和光周期相协调。春化作用，即长时间暴露于冬季寒冷中会导致植物在次年春季具备开花能力的过程，就是温度对开花时间影响的一个例子。在不同的植物类群中，有不同的基因参与春化作用，这表明春化系统在不同植物类群中是独立进化的。鉴于被子植物科在温暖的古气候中就已开始分化，而在这种气候下春化反应并无优势，春化系统的趋同进化也就不足为奇了。在此，我们综述了在三种不同植物类群中已知的春化反应：十字花科植物（拟南芥）、苋科植物（甜菜）和早熟禾亚科植物（小麦、大麦和短柄草）。我们还讨论了将短柄草用作研究早熟禾亚科植物开花和春化作用的模式系统的优势。最后，我们讨论了禾本科植物中Ghd7/VRN2基因家族的进化和功能。
