Functional conservation and diversification of class E floral homeotic genes in rice (Oryza sativa)
Functional conservation and diversification of class E floral homeotic genes in rice (Oryza sativa)
复制标题
水稻E类花同源基因的功能保护和多样化（Oryza sativa）
DOI：
10.1111/j.1365-313x.2009.04101.x
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发表时间：
2010-03-01
期刊：
影响因子：
7.2
通讯作者：
Meng, Zheng
中科院分区：
文献类型：
--
作者：
Cui, Rongfeng;Han, Jiakun;Meng, Zheng
不同真双子叶开花植物的突变体分析表明，SEPALLATA样MADS-box基因是萼片，花瓣，雄蕊和心皮的特化所必需的，花的决定性，从而定义E类花器官身份基因。SEP类基因编码MADS结构域转录因子，构成被子植物特有的基因分支，其成员在真双子叶植物中表现出显著不同程度的冗余和亚功能化。为了更好地了解SEP样基因在被子植物中的进化动态，我们敲除了水稻（Oryza sativa）的SEP样基因，水稻是显花植物中真双子叶植物的远亲。在OsMADS 7和OsMADS 8中受影响的植物表现出严重的表型，包括延迟开花，浆片、雄蕊和心皮同源异型变化成内稃/外稃样器官，以及花决定性的丧失。同时敲除OsMADS 1、OsMADS 5、OsMADS 7和OsMADS 8四个水稻类SEP基因，导致除外稃外的所有花器官同源异型转化为叶状器官。这模拟了用拟南芥的sep 1 sep 2 sep 3 sep 4四重突变体观察到的表型。详细分析的空间和时间的mRNA表达和蛋白质相互作用模式对应于不同的水稻SEP样基因显示出很强的相似性，但也基因特异性差异。这些发现揭示了自大约1.5亿年前真双子叶植物和单子叶植物分离以来，SEP样基因在指定花的决定性和器官身份方面的保守性。然而，它们也表明了单子叶植物特异性的新功能化和亚功能化事件，因此强调了SEP样基因的进化动力学。此外，我们的研究结果证实了草的浆片与真双子叶植物花瓣同源的观点。
P>Mutant analyses in different eudicotyledonous flowering plants demonstrated that SEPALLATA-like MADS-box genes are required for the specification of sepals, petals, stamens and carpels, and for floral determinacy, thus defining class E floral organ identity genes. SEP-like genes encode MADS-domain transcription factors and constitute an angiosperm-specific gene clade whose members show remarkably different degrees of redundancy and sub-functionalization within eudicots. To better understand the evolutionary dynamics of SEP-like genes throughout the angiosperms we have knocked down SEP-like genes of rice (Oryza sativa), a distant relative of eudicots within the flowering plants. Plants affected in both OsMADS7 and OsMADS8 show severe phenotypes including late flowering, homeotic changes of lodicules, stamens and carpels into palea/lemma-like organs, and a loss of floral determinacy. Simultaneous knockdown of the four rice SEP-like genes OsMADS1, OsMADS5, OsMADS7 and OsMADS8, leads to homeotic transformation of all floral organs except the lemma into leaf-like organs. This mimics the phenotype observed with the sep1 sep2 sep3 sep4 quadruple mutant of Arabidopsis. Detailed analyses of the spatial and temporal mRNA expression and protein interaction patterns corresponding to the different rice SEP-like genes show strong similarities, but also gene-specific differences. These findings reveal conservation of SEP-like genes in specifying floral determinacy and organ identities since the separation of eudicots and monocots about 150 million years ago. However, they indicate also monocot-specific neo- and sub-functionalization events and hence underscore the evolutionary dynamics of SEP-like genes. Moreover, our findings corroborate the view that the lodicules of grasses are homologous to eudicot petals.