BRASSINOSTEROID SIGNALING IN ARABIDOPSIS

植物对光的反应能力对它们的生存至关重要。 最近的证据表明，油菜素类固醇（BR）在光反应的鉴定油菜素类固醇反应成分的极大兴趣。 不能合成BR的幼苗即使在黑暗中生长也能发育成光生长的植物。 此外，这些突变体揭示了BR在整个发育过程中的重要作用。传统的筛选试图识别BR反应和信号通路的组成部分，但由于未能发现除一个基因BRI 1以外的所有基因的突变而受到阻碍。 对于为什么在这些筛选中仅鉴定出一个基因的几种解释是可能的。 最可能的两个是BR反应所需的基因参与其他途径（从而产生不同于BR合成突变体的表型）和/或这些基因是多余的或对生存力至关重要的。我将使用新的方法来绕过这些障碍，并确定BR信号的新组件。 在这些方法中的第一个，不同的拟南芥生态型的数量性状基因座分析将允许我首先本地化，然后克隆新的BR反应元件。 其次，拟南芥BR与生长素协同作用的研究将为BR的研究开辟新的领域。 这个激素通路之间通信的惊人例子提供了一个机会，可以更好地理解每种激素单独的信号传导以及它们之间的交叉节点。

Plants' ability to respond to light is crucial for their survival. Recent evidence implicating brassinosteroids (BRs) in the light response has made the identification of brassinosteroid response components of great interest. Seedlings unable to synthesize BRs develop as light-grown plants even when grown in darkness. Moreover, these mutants reveal a significant role for BRs throughout development. Traditional screens attempting to identify components of the BR response and signaling pathway have been hampered by failure to uncover mutations in all but one gene, BRI1. Several explanations for why only one gene was identified in these screens are possible. Two of the most likely are that the genes required for BR response are involved in other pathways (thus yielding phenotypes distinct from BR synthetic mutants) and/or that these genes are redundant or essential for viability. I will use novel approaches to circumvent these obstacles and identify new components of BR signaling. In the first of these approaches, quantitative trait loci analysis on disparate Arabidopsis ecotypes will allow me to first localize and then clone new BR response elements. Secondly, characterization of BR: auxin synergy in Arabidopsis will define a new niche of BR research. This striking example of communication between hormone pathways presents an opportunity to better understand the signaling of each hormone alone as well as the nodes of intersection between them.