Ehd4 encodes a novel and Oryza-genus-specific regulator of photoperiodic flowering in rice.
Ehd4 encodes a novel and Oryza-genus-specific regulator of photoperiodic flowering in rice.
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DOI：
10.1371/journal.pgen.1003281
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发表时间：
2013
期刊：
影响因子：
4.5
通讯作者：
Wan JM
中科院分区：
文献类型：
--
作者：
Gao H;Zheng XM;Fei G;Chen J;Jin M;Ren Y;Wu W;Zhou K;Sheng P;Zhou F;Jiang L;Wang J;Zhang X;Guo X;Wang JL;Cheng Z;Wu C;Wang H;Wan JM
陆地植物已经进化出越来越复杂的开花时间（或作物的抽穗期）调节模式。水稻（Oryza sativa L.）是一种短日照植物，在短日照条件下开花更快，但在长日照条件下开花延迟。先前的研究表明，最初在长日照植物（拟南芥）中鉴定的CO-FT模块在短日照植物（水稻中的Hd 1-Hd 3a）中是进化保守的。然而，在水稻中，有一个独特的Ehd 1依赖的开花途径，是Hd 1独立的。在这里，我们报告的Ehd 1，早抽穗期4（Ehd 4）的正调节剂的分离和表征。EHD 4突变体在自然长日照条件下显示从不开花的表型。基于图位的克隆显示，Ehd 4编码一种新的CCCH型锌指蛋白，该蛋白定位于细胞核，能够在体外与核酸结合，并在酵母中反式激活转录，这表明它可能作为转录调节因子发挥作用。Ehd 4在幼叶中表达最活跃，其昼夜表达模式与Ehd 1在短日照和长日照条件下的表达模式相似。我们发现，Ehd 4上调的“成花素”基因Hd 3a和RFT 1通过Ehd 1的表达，但它的行为独立于其他已知的Ehd 1调节。值得注意的是，Ehd 4在包括野生稻和栽培稻在内的稻属中高度保守，但在其他物种中没有同源物，这表明Ehd 4是沿着稻属在进化过程中从禾本科的多样化而起源的。我们的结论是，Ehd 4是一个新的水稻属特异性调节Ehd 1，它在光周期控制水稻开花时间起着至关重要的作用。大米是人类重要的热量来源。开花时间决定作物的种植季节和区域适应性。水稻起源于其野生祖先，O。rufipogon，主要分布于热带地区，北方界约28 °N，距今已有1万多年。然而，栽培稻现在在亚洲广泛种植，其北方界限接近53 °N。栽培稻的北移必须伴随着人类在驯化和育种过程中对开花时间性状的选择，以确保在寒冷天气来临之前获得收获。通过鉴定一个在自然长日照条件下从不开花的水稻突变体，我们克隆了Ehd 4作为一种新的转录调节因子，它通过激活两个“成花素”基因（开花起始的信号）来促进开花。结果表明，Ehd 4具有两种主要的单倍型：Hap_2是分布在低纬度和高海拔地区的籼稻材料的主要单倍型，Hap_3是分布在高纬度和高海拔地区的粳稻材料的主要单倍型。遗传研究表明，Hap_3在NLD下促进开花的功能更强，这意味着Ehd 4可能有助于栽培稻向高纬度地区的北扩和区域适应性。
Land plants have evolved increasingly complex regulatory modes of their flowering time (or heading date in crops). Rice (Oryza sativa L.) is a short-day plant that flowers more rapidly in short-day but delays under long-day conditions. Previous studies have shown that the CO-FT module initially identified in long-day plants (Arabidopsis) is evolutionary conserved in short-day plants (Hd1-Hd3a in rice). However, in rice, there is a unique Ehd1-dependent flowering pathway that is Hd1-independent. Here, we report isolation and characterization of a positive regulator of Ehd1, Early heading date 4 (Ehd4). ehd4 mutants showed a never flowering phenotype under natural long-day conditions. Map-based cloning revealed that Ehd4 encodes a novel CCCH-type zinc finger protein, which is localized to the nucleus and is able to bind to nucleic acids in vitro and transactivate transcription in yeast, suggesting that it likely functions as a transcriptional regulator. Ehd4 expression is most active in young leaves with a diurnal expression pattern similar to that of Ehd1 under both short-day and long-day conditions. We show that Ehd4 up-regulates the expression of the “florigen” genes Hd3a and RFT1 through Ehd1, but it acts independently of other known Ehd1 regulators. Strikingly, Ehd4 is highly conserved in the Oryza genus including wild and cultivated rice, but has no homologs in other species, suggesting that Ehd4 is originated along with the diversification of the Oryza genus from the grass family during evolution. We conclude that Ehd4 is a novel Oryza-genus-specific regulator of Ehd1, and it plays an essential role in photoperiodic control of flowering time in rice. Rice is an important source of calories for mankind. Flowering time determines cropping seasons and regional adaptability of crops. Rice is originated from its wild progenitor, O. rufipogon, which is mainly distributed at tropical latitudes with a northern limit about 28 °N, more than 10,000 years ago. However, cultivated rice is now grown widely in Asia, with a northern limit of nearly 53 °N. The northward expansion of cultivated rice must be accompanied by human selection of the flowering time trait during domestication and breeding, to secure a harvest before cold weather approaches. By identifying a rice mutant that never flowers under natural long-day conditions (NLDs), we cloned Ehd4 as a novel transcriptional regulator that promotes flowering through activation of two “florigen” genes, the signals for flowering initiation. We found that Ehd4 has two major haplotypes: Hap_2 is the major haplotype in indica accessions mostly distributed in lower latitude and elevation zones, whereas Hap_3 is the major haplotype in japonica accessions mostly distributed in higher latitudes and elevation zones. Genetic studies showed that Hap_3 is functionally more potent in promoting flowering under NLDs, implying that Ehd4 may have contributed to the northward expansion and regional adaptability of cultivated rice into higher latitudes.
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影响因子：
5.1
作者：
Bart R;Chern M;Park CJ;Bartley L;Ronald PC
通讯作者：
Ronald PC
DOI：
10.1083/jcb.200811072
发表时间：
2009-04-20
期刊：
The Journal of cell biology
影响因子：
--
作者：
Hurt JA;Obar RA;Zhai B;Farny NG;Gygi SP;Silver PA
通讯作者：
Silver PA
影响因子：
7.4
作者：
Kim, Song Lim;Lee, Shinyoung;An, Gynheung
通讯作者：
An, Gynheung
影响因子：
7.4
作者：
Matsubara, Kazuki;Yamanouchi, Utako;Yano, Masahiro
通讯作者：
Yano, Masahiro
影响因子：
56.9
作者：
Liu, Hongtao;Yu, Xuhong;Lin, Chentao
通讯作者：
Lin, Chentao