Floral organ identity genes in the orchid Dendrobium crumenatum.
Floral organ identity genes in the orchid Dendrobium crumenatum.
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DOI：
10.1111/j.1365-313x.2006.02669.x
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发表时间：
2006-04
期刊：
影响因子：
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通讯作者：
Yifeng Xu;L. Teo;Jing Zhou;Prakash P. Kumar;Hao Yu
中科院分区：
文献类型：
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作者：
Yifeng Xu;L. Teo;Jing Zhou;Prakash P. Kumar;Hao Yu
兰花是兰科的成员，是开花植物中最大的家族之一。在被子植物中，兰花的花型，特别是花的结构和器官特征是独一无二的。ABCDE模型被提出作为解释不同植物类群花发育的一般模型，但该模型在多大程度上适用于兰花尚不清楚。为了研究兰花花发育的调控机制，我们从石斛（Dendrobium crumenatum）中分离出A、B、C、D和E功能基因候选基因。这些基因包括AP2-、PI/GLO-、AP3/DEF-、AG-和sep样基因。这些基因的表达谱与拟南芥同源植物在花形态方面表现出不同的模式。功能研究表明，DcOPI和dcoagul1在拟南芥中可分别替代PI和AG的功能。利用嵌合抑制基因沉默技术，发现DcOAP3A是另一个推测的B功能基因。酵母双杂交分析表明，DcOAP3A/B和DcOPI可以形成异源二聚体。这些异源二聚体可以进一步与DcOSEP相互作用，形成更高的蛋白质复合物，类似于它们在ediicots中的同源物。研究结果表明，拟南芥和兰花在B和C功能基因上存在部分保守性。然而，基因复制可能导致了基因表达和调控上的差异，进而导致了功能上的差异，从而导致了兰科植物独特的花体发育。
Orchids are members of Orchidaceae, one of the largest families in the flowering plants. Among the angiosperms, orchids are unique in their floral patterning, particularly in floral structures and organ identity. The ABCDE model was proposed as a general model to explain flower development in diverse plant groups, however the extent to which this model is applicable to orchids is still unknown. To investigate the regulatory mechanisms underlying orchid flower development, we isolated candidates for A, B, C, D and E function genes from Dendrobium crumenatum. These include AP2-, PI/GLO-, AP3/DEF-, AG- and SEP-like genes. The expression profiles of these genes exhibited different patterns from their Arabidopsis orthologs in floral patterning. Functional studies showed that DcOPI and DcOAG1 could replace the functions of PI and AG in Arabidopsis, respectively. By using chimeric repressor silencing technology, DcOAP3A was found to be another putative B function gene. Yeast two-hybrid analysis demonstrated that DcOAP3A/B and DcOPI could form heterodimers. These heterodimers could further interact with DcOSEP to form higher protein complexes, similar to their orthologs in eudicots. Our findings suggested that there is partial conservation in the B and C function genes between Arabidopsis and orchid. However, gene duplication might have led to the divergence in gene expression and regulation, possibly followed by functional divergence, resulting in the unique floral ontogeny in orchids.