Directing floral timing through genetic variation in the plant circadian clock

开花时间受生物钟的强烈调控，生物钟驱动光周期开花。最近，我们探索了双子叶拟南芥中时钟的自然等位基因多样性，并发现了对环境的“记忆”。此外，我们还表明，在田间条件下，时钟变化对花期有很大的指导作用。克隆了一个昼夜节律的数量性状基因座，发现了开花期基因早花3(ELF3)的变异。在这里，我们将进一步探索时钟基因的等位基因变异，以确定引导光周期开花的关键基因座。首先，我们将完成来自极不同纬度的材料衍生的新的拟南芥重组自交系群体的构建，并以千碱基的分辨率绘制这些品系的基因组图谱。这些种群将根据时钟和开花时间的变化进行评分；将建立动态关联。总而言之，指导季节性开花的时钟基因变异的组成部分将被识别。其次，我们将利用大麦ELF3现有的和新产生的变异来研究单子叶大麦开花的昼夜节律控制的分子遗传学。该基因可能是季节性基因PPD-H1的直接调节者。这第二个程序应该揭示双子叶/单子叶生物钟的保守性，并识别生物钟基因ELF3上的等位基因变异，这些变异可以直接用于大麦育种。

Flowering time is strongly regulated by the circadian clock, which drives photoperiodic flowering. We recently explored natural allelic diversity of the clock in the dicot Arabidopsis and found a "memory" of the proceeding environment. Furthermore, we showed that clock variation has a large role in directing flowering time under field conditions. Cloning of one circadian quantitative trait locus revealed variation at the flowering-time gene EARLY FLOWERING 3 (ELF3). Here we will further explore allelic variation in clock genes to define key loci that direct photoperiodic flowering. Firstly, we will complete the construction of new Arabidopsis recombinant inbred populations derived from accessions originating from extremely differing latitudes, and map the genomes of these lines at kilobase resolution. These populations will be scored for variation in the clock and flowering time; dynamic correlations will be constructed. Together, components underling clock-gene variation that directs seasonal flowering will be identified. Secondly, we will examine the molecular genetics of circadian control of flowering in the monocot barley using existing and newly generated variation at barley ELF3. This gene is the likely direct regulator of the seasonality locus Ppd-H1. This second program should reveal dicot/monocot clock conservations and identify allelic variation at the circadian-clock gene ELF3 that could be directly used in barley breeding programs.