(封面图片:矮牵牛花Petunia hybrida为科学家研究聚伞花序的发生机制提供了一种很好的模型。研究发现一种被称为EVERGREEN的WOX基因是聚伞花序结构产生的关键因子。)
植物种类根据它们各自开花的时间和地点而发生分化。花能通过顶端分生组织(apical meristem)、侧生分生组织(lateral meristem)分别产生,也可以通过以上两者同时产生,这就分别产生了三种主要的花序种类:总状花序(raceme)、聚伞花序(cyme)以及圆锥花序(panicle)。其中产生总状花序结构的机制已经在拟南芥(Arabidopsis)和金鱼草(Antirrhinum)中得到解释,而为了了解聚伞花序结构是如何产生的,来自荷兰的Rebocho等科学家研究了改变矮牵牛花序的一些基因变异,并且将研究的结果以封面文章的形式发表在2008年9月16日出版的《发育细胞》(Developmental Cell)上。
在研究中科学家们发现,一种被称为EVERGREEN(EVG)的基因负责编译一种WOX同源结构域蛋白,这种蛋白只在初始侧生花序分生组织(IMs)中得到表达,并且促使它们从顶端花分生组织(FM)中分离出来。在聚伞花序结构中,花序最终将形成一种典型的聚伞状Z字形构造,而导致矮牵牛花的聚伞状花序结构最终变为单生花的变异完全抑制了evg基因。
最终科学家表示,数据显示EVG基因在花序结构的变化方面起到了至关重要的作用,并且研究结果还显示出在分生组织的增殖以及种类特征之间存在一种出人意料的联系。(生物谷Bioon.com)
生物谷推荐原始出处:
Developmental Cell,Vol 15, 437-447, 16 September 2008,Alexandra B. Rebocho, Ronald Koes
Role of EVERGREEN in the Development of the Cymose Petunia Inflorescence
Alexandra B. Rebocho,Mattijs Bliek,Elske Kusters,Rob Castel,Antonia Procissi,Ilja Roobeek,Erik Souer,and Ronald Koes,
Institute for Molecular and Cell Biology, Graduate School of Experimental Plant Sciences, Vrije Universiteit, de Boelelaan 1085, 1081HV Amsterdam, The Netherlands
Plants species diverge with regard to the time and place where they make flowers. Flowers can develop from apical meristems, lateral meristems, or both, resulting in three major inflorescence types known as racemes, cymes, and panicles, respectively. The mechanisms that determine a racemose architecture have been uncovered inArabidopsis and Antirrhinum. To understand how cymes are specified, we studied mutations that alter the petunia inflorescence. Here we show that EVERGREEN (EVG) encodes a WOX homeodomain protein, which is exclusively expressed in incipient lateral inflorescence meristems (IMs), promoting their separation from the apical floral meristem (FM). This is essential for activation of DOUBLE TOP and specification of floral identity. Mutations that change the cymose petunia inflorescence into a solitary flower fully suppress the evg phenotype. Our data suggest a key role for EVG in the diversification of inflorescence architectures and reveal an unanticipated link between the proliferation and identity of meristems.