Model for perianth formation in orchids
Model for perianth formation in orchids
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DOI：
10.1038/nplants.2015.46
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发表时间：
2015-04-27
期刊：
影响因子：
18
通讯作者：
Yang, Chang-Hsien
中科院分区：
文献类型：
--
作者：
Hsu, Hsing-Fun;Hsu, Wei-Han;Yang, Chang-Hsien
兰科是天门冬目（Asparagales）下的兰科，包含约880属（1-3）中超过20，000种公认的物种。与大多数辐射对称的花相反，兰花通常具有左右对称的对称性，具有显著分化良好的唇瓣（唇），通过采用视觉，香味和触觉线索作为主要的传粉者引诱剂（4-7）。控制辐射对称花（如拟南芥）图案形成的遗传模型是众所周知的。然而，萼片/花瓣/唇决定的机制仍然不清楚。在这里，我们展示了一个保守的原则，被称为花被（P）代码，这涉及到两个蛋白质复合物之间的竞争，含有不同的AP 3/AGL 6同源物，以确定复杂的花被图案在兰花的形成。在P编码中，高阶异源四聚体SP（萼片/花瓣）复合物（OAP 3 -1/OAGL 6 - 1/OPI）指定萼片/花瓣的形成，而L（唇）复合物（OAP 3 -2/OAGL 6 -2/OAGL 6 -2/OPI）是唇形成所专门需要的。该模型通过使用病毒诱导的基因沉默（VIGS）策略抑制唇中的L复合物活性将文心兰和蝴蝶兰中的唇转化为萼片/花瓣结构来验证。对兰科四个不同亚科的全面研究进一步验证了P密码，并显着扩展了目前关于兰花花被形成机制和途径的知识。
Orchidaceae, the orchid family under the order Asparagales, contains more than 20,000 accepted species in approximately 880 genera(1-3). In contrast to most flowers of actinomorphic symmetry, orchid flowers typically have zygomorphic symmetry with a striking well-differentiated labellum (lip) that acts as the main pollinator attractant by employing visual, fragrance and tactile cues(4-7). Genetics models controlling patterning formation of actinomorphic flowers, such as Arabidopsis, are well known. However, the mechanisms of sepal/petal/lip determination remain obscure. Here, we demonstrate a conserved principle, called the Perianth (P) code, which involves competition between two protein complexes containing different AP3/AGL6 homologues to determine the formation of the complex perianth patterns in orchids. In the P code, the higher-order heterotetrameric SP (sepal/petal) complex (OAP3-1/OAGL6-1/OAGL6-1/OPI) specifies sepal/petal formation, whereas the L (lip) complex (OAP3-2/OAGL6-2/OAGL6-2/OPI) is exclusively required for lip formation. This model is validated by the conversion of lips into sepal/petal structures in Oncidium and Phalaenopsis orchids through the suppression of the proposed L complex activity in lips using the virus-induced gene silencing (VIGS) strategy. A comprehensive examination of four different subfamilies of Orchidaceae further validates the P code and significantly extends the current knowledge regarding the mechanism and pathways of perianth formation in orchids.