Mutation at the circadian clock gene EARLY MATURITY 8 adapts domesticated barley (Hordeum vulgare) to short growing seasons
Mutation at the circadian clock gene EARLY MATURITY 8 adapts domesticated barley (Hordeum vulgare) to short growing seasons
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DOI：
10.1073/pnas.1120496109
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发表时间：
2012-05-22
影响因子：
11.1
通讯作者：
Laurie, David A.
中科院分区：
文献类型：
--
作者：
Faure, Sebastien;Turner, Adrian S.;Laurie, David A.
生物钟是一种自主振荡器，能产生周期约为24小时的内源性生物节律。这种生物钟使生物体能够根据环境可预测的每日和季节性变化来协调其新陈代谢和发育。在植物中，昼夜节律对进化适应性和农业生产力都有贡献。然而，我们发现，通过利用早熟8（eam8）突变（也称为mat - a）培育的用于短生长季的商业大麦品种，在生物钟基因表达和生物钟输出方面受到严重损害。我们确定EAM8是拟南芥生物钟调节因子EARLY FLOWERING3（ELF3）的大麦直系同源基因，并证明eam8加速了从营养生长到生殖生长以及花序发育的转变。我们提出，当大麦种植转移到欧洲高纬度短季环境时，eam8被选中是因为它能使含有先前选择的光周期反应基因Ppd - H1的晚花突变的遗传背景快速开花。我们表明eam8突变体中花激活因子HvFT1的表达增加，这与Ppd - H1的等位基因变异无关。对独立eam8突变的选择表明，尽管存在明显的生物钟缺陷，但这种策略有助于大麦适应短生长季并扩大其地理范围。
The circadian clock is an autonomous oscillator that produces endogenous biological rhythms with a period of about 24 h. This clock allows organisms to coordinate their metabolism and development with predicted daily and seasonal changes of the environment. In plants, circadian rhythms contribute to both evolutionary fitness and agricultural productivity. Nevertheless, we show that commercial barley varieties bred for short growing seasons by use of early maturity 8 (eam8) mutations, also termed mat-a, are severely compromised in clock gene expression and clock outputs. We identified EAM8 as a barley ortholog of the Arabidopsis thaliana circadian clock regulator EARLY FLOWERING3 (ELF3) and demonstrate that eam8 accelerates the transition from vegetative to reproductive growth and inflorescence development. We propose that eam8 was selected as barley cultivation moved to high-latitude short-season environments in Europe because it allowed rapid flowering in genetic backgrounds that contained a previously selected late-flowering mutation of the photoperiod response gene Ppd-H1. We show that eam8 mutants have increased expression of the floral activator HvFT1, which is independent of allelic variation at Ppd-H1. The selection of independent eam8 mutations shows that this strategy facilitates short growth-season adaptation and expansion of the geographic range of barley, despite the pronounced clock defect.