Control of corolla monosymmetry in the Brassicaceae Iberis amara
Control of corolla monosymmetry in the Brassicaceae Iberis amara
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DOI：
10.1073/pnas.0705338104
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发表时间：
2007-10-16
影响因子：
11.1
通讯作者：
Zachgo, Sabine
中科院分区：
文献类型：
--
作者：
Busch, Andrea;Zachgo, Sabine
形态学上的新发现使花的结构发生了巨大的变化。花的单对称性是一种新奇的现象，它被认为在被子植物的进化过程中独立地进化了好几次。到目前为止，单对称调节的分析主要集中在单对称占优势的类群中的物种，如唇形科和豆科。在金鱼草中，单对称花冠的形成由TCP转录因子CYCLOIDEA（CYC）和DICHOTOMA（DICH）的活性所指定。结果表明，单对称性的建立可能需要CYC同源物的早期不对称花表达，该表达需要维持到花晚期。为了了解如何CYC同源物可能已被招募在进化过程中建立单对称性，我们的特点是可能的CYC直向同源物LATCP1从阿马拉（菊科）。Icelandis属的物种形成单对称的花冠，而菊科则由多对称花冠的属占主导地位。而不是四个相同大小的花瓣，L阿马拉产生两个小的轴向和两个大的远轴花瓣。laTCP1表达的时间不同于其拟南芥同源物TCP1和其他CYC同源物。LATCP1缺乏一个不对称的早期表达，但显示出非常强的差异表达的花冠在花的后期阶段，当最强的不平等的花瓣生长发生。偶尔发生的peloricipine花的变种和比较功能的研究，在拟南芥中的TCP同源物的分析表明，一个改变的时间laTCP1的表达在拟南芥科的重要性，以管理形成一个单对称的花冠。
Establishment of morphological novelties has contributed to the enormous diversification of floral architecture. One such novelty, flower monosymmetry, is assumed to have evolved several times independently during angiosperm evolution. To date, analysis of monosymmetry regulation has focused on species from taxa where monosymmetry prevails, such as the Lamiales and Fabaceae. In Antirrhinum majus, formation of a monosymmetric corolla is specified by the activity of the TCP transcription factors CYCLOIDEA (CYC) and DICHOTOMA (DICH). It was shown that establishment of monosymmetry likely requires an early asymmetric floral expression of CYC homologs that needs to be maintained until late floral stages. To understand how CYC homologs might have been recruited during evolution to establish monosymmetry, we characterized the likely CYC ortholog laTCP1 from Iberis amara (Brassicaceae). Species of the genus Iberis form a monosymmetric corolla, whereas the Brassicaceae are otherwise dominated by genera developing a polysymmetric corolla. Instead of four equally sized petals, L amara produces two small aclaxial and two large abaxial petals. The timing of laTCP1 expression differs from that of its Arabidopsis homolog TCP1 and other CYC homologs. laTCP1 lacks an asymmetric early expression but displays a very strong differential expression in the corolla at later floral stages, when the strongest unequal petal growth occurs. Analysis of occasionally occurring peloriciberis flower variants and comparative functional studies of TCP homologs in Arabidopsis demonstrate the importance of an altered temporal laTCP1 expression within the Brassicaceae to govern the formation of a monosymmetric corolla.