OsMADS50 and OsMADS56 function antagonistically in regulating long day (LD)-dependent flowering in rice
OsMADS50 and OsMADS56 function antagonistically in regulating long day (LD)-dependent flowering in rice
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DOI：
10.1111/j.1365-3040.2009.02008.x
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发表时间：
2009-10-01
影响因子：
7.3
通讯作者：
An, Gynheung
中科院分区：
文献类型：
--
作者：
Ryu, Choong-Hwan;Lee, Shinyoung;An, Gynheung
在许多热带和亚热带地区，水稻（Oryza sativa L.）在长日照（LD）下生长。因此，LD在诱导水稻开花信号中一定发挥着重要作用。然而，很少有人知道LD依赖开花信号的物种。OsMADS 50基因与拟南芥SOC 1基因高度同源，是一个开花的正调控基因。然而，其详细的光周期机制尚未阐明。本文对OsMADS 50及其相关基因OsMADS 56进行了功能分析。OsMADS 50的敲除仅在LD条件下引起晚开花表型。过量表达OsMADS 56（56 OX）也导致LD下开花延迟。在Osmads 50突变体和56 OX转基因植株中，Ehd 1、Hd 3a和RFT 1的转录水平降低，而OsLFL 1的转录水平升高。另一方面，OsGI、Hd 1、OsId 1、OsDof 12、Ghd 7、Hd 6和SE 5的mRNA水平没有变化。这些观察结果表明OsMADS 50和OsMADS 56通过OsLFL 1-Ehd 1在调节LD依赖的开花中具有拮抗作用。酵母双杂交和免疫共沉淀分析表明，这两种蛋白质之间的相互作用，以及它们的同源二聚体的形成。这些结果表明OsMADS 50和OsMADS 56可能形成调控下游靶基因的复合物。
In much of the tropics and subtropics, rice (Oryza sativa L.) is grown under long days (LDs). Therefore, LD must play a major role in inducing flowering signal in rice. However, little is known on LD-dependent flowering signal in the species. We previously reported that OsMADS50, which is highly homologous to Arabidopsis SOC1, functions as a positive regulator for flowering. However, its detailed photoperiodic mechanism was not yet elucidated. Here, we report the functional analysis of OsMADS50 and its closely related gene OsMADS56. Knock-out of OsMADS50 caused a late-flowering phenotype only under LD conditions. Overexpression of OsMADS56 (56OX) also resulted in delayed flowering under LD. In the osmads50 mutants and 56OX transgenic plants, transcripts of Ehd1, Hd3a and RFT1 were reduced, although that of OsLFL1 increased. On the other hand, mRNA levels of OsGI, Hd1, OsId1, OsDof12, Ghd7, Hd6 and SE5 were unchanged. These observations imply that OsMADS50 and OsMADS56 function antagonistically through OsLFL1-Ehd1 in regulating LD-dependent flowering. Yeast two-hybrid and co-immunoprecipitation analyses indicated an interaction between those two proteins as well as their formation of homodimers. These results suggest that OsMADS50 and OsMADS56 may form a complex that regulates downstream target genes.