Genetic interactions between diverged alleles of Early heading date 1 (Ehd1) and Heading date 3a (Hd3a)/ RICE FLOWERING LOCUS T1 (RFT1) control differential heading and contribute to regional adaptation in rice (Oryza sativa)

Jing Zhao, Hongyi Chen, Ding Ren, Huiwu Tang, Rong Qiu, Jinglei Feng, Yunming Long, Baixiao Niu, Danping Chen, Tianyu Zhong, Yao-Guang Liu, Jingxin Guo
New Phytologist, 2015, 208(3): 936-948  DOI: 10.1111/nph.13503;      追溯原文......本站官方QQ群:62473826
florigen; heading date; natural allelic variation; rice (Oryza sativa); RICE FLOWERING LOCUS T1 (RFT1)

  • Initiation of flowering, also called heading, in rice (Oryza sativa) is determined by the florigens encoded by Heading date 3a (Hd3a) and RICE FLOWERING LOCUS T1 (RFT1). Early heading date 1 (Ehd1) regulates Hd3a and RFT1. However, different rice varieties have diverged alleles of Ehd1 and Hd3a/RFT1 and their genetic interactions remain largely unclear.
  • Here we generated three segregating populations for different combinations of diverged Ehd1 and Hd3a/RFT1 alleles, and analyzed their genetic interactions between these alleles. We demonstrated that, in an ehd1 mutant background, Hd3a was silenced, but RFT1 was expressed (although at lower levels than in plants with a functional Ehd1) under short-day (SD) and long-day (LD) conditions.
  • We identified a nonfunctional RFT1 allele (rft1); the lines carrying homozygous ehd1 and Hd3a/rft1 failed to induce the floral transition under SD and LD conditions. Like Hd3a, RFT1 also interacted with 14-3-3 proteins, the florigen receptors, but a nonfunctional RFT1 with a crucial E105K mutation failed to interact with 14-3-3 proteins. Furthermore, analyses of sequence variation and geographic distribution suggested that functional RFT1 alleles were selected during rice adaptation to high-latitude regions.
  • Our results demonstrate the important roles of RFT1 in rice flowering and regional adaptation.
  • 水稻Ehd1Hd3a/RFT1不同等位基因间的遗传互作控制不同开花时间并有助于地区适应性

  • 开花起始在水稻中又叫抽穗,是由Hd3aRFT1编码的成花素决定的。Ehd1调控Hd3aRFT1。但是,不同水稻品种具有不同的Ehd1Hd3a/RFT1等位基因,它们的遗传互作仍不清楚。
  • 本文我们构建了三个分离群体,它们由不同Ehd1Hd3a/RFT1不同等位基因组合,分析了这些等位基因间的遗传互作。我们发现在ehd1突变体背景下,Hd3a是沉默的,但是短日照条件(SD)和长日照条件(LD)下,RFT1有表达(尽管与Ehd1有功能的植株相比,它的表达水平比较低)。
  • 我们鉴定了一个无功能的RFT1等位基因(rft1),在SD和LD条件下,携带纯合ehd1Hd3a/rft1株系不能诱导花的转变。与Hd3a类似,RFT1也能够与成花素受体14-3-3蛋白互作,但是无功能的RFT1由于一个重要突变E105K,不能够与14-3-3蛋白互作。此外,序列差异分析以及地理分布表明,在水稻对高纬度地区的适应过程中,有功能RFT1等位基因受到了选择。
  • 我们的结果表明RFT1在水稻开花以及地区适应性中发挥了重要作用。

  • 基因列表
      早穗基因 Ehd1
      成花素基因;抽穗期基因;生育期基因;光周期敏感基因;感光基因 Hd3a; FT
      成花素基因 RFT1; FT-L3