Creative Research Initiatives, Division of Life Sciences, Korea University, Seoul 136-701, Republic of Korea.
Plant Sci. 2012 Apr;185-186:97-104. doi: 10.1016/j.plantsci.2011.09.003. Epub 2011 Sep 12.
MADS-box transcription factors play pivotal roles in several aspects of plant growth and development. The Arabidopsis SHORT VEGETATIVE PHASE (SVP) protein mediates the integration of signals involved in the control of flowering time and flower development by interacting with MADS-box proteins. In the rice genome, three SVP-like genes (OsMADS22, OsMADS47, and OsMADS55) are present. To investigate the functional conservation of these SVP-like genes in rice and Arabidopsis, the phenotypes of transgenic Arabidopsis plants overexpressing OsMADS22 and OsMADS55 were analyzed. Overexpression of OsMADS22 and OsMADS55 led to abnormal floral morphologies including leaf-like sepals, whereas only OsMADS55 expression caused delayed flowering via downregulation of FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1). Yeast two-hybrid assays revealed that OsMADS22 and OsMADS55 interacted with Arabidopsis AGL24 and AP1, but only OsMADS55 interacted with FLC. Overexpression of OsMADS55, but not OsMADS22, complemented the early flowering phenotype and ambient temperature-insensitive flowering phenotype seen in svp mutants, suggesting that OsMADS55 regulates flowering time associated with ambient temperature responses in Arabidopsis. Taken together, our data are consistent with functional conservation and diversification between Arabidopsis and rice SVP-like genes involved in controlling flowering time and flower development.
MADS 框转录因子在植物生长和发育的几个方面发挥着关键作用。拟南芥短日植物（SVP）蛋白通过与 MADS 框蛋白相互作用，介导参与调控开花时间和花发育的信号整合。在水稻基因组中，存在三个 SVP 样基因（OsMADS22、OsMADS47 和 OsMADS55）。为了研究这些 SVP 样基因在水稻和拟南芥中的功能保守性，分析了过量表达 OsMADS22 和 OsMADS55 的转基因拟南芥植物的表型。过量表达 OsMADS22 和 OsMADS55 导致花形态异常，包括叶状萼片，而仅 OsMADS55 的表达通过下调 FLOWERING LOCUS T（FT）和 SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1（SOC1）导致开花延迟。酵母双杂交实验表明，OsMADS22 和 OsMADS55 与拟南芥 AGL24 和 AP1 相互作用，但只有 OsMADS55 与 FLC 相互作用。过量表达 OsMADS55，但不是 OsMADS22，可补充 svp 突变体中观察到的早期开花表型和环境温度不敏感的开花表型，表明 OsMADS55 调节与环境温度反应相关的开花时间。综上所述，我们的数据与拟南芥和水稻 SVP 样基因在控制开花时间和花发育方面的功能保守性和多样化一致。
