Environmental and hormonal control of shoot branching

枝条分枝的环境和激素控制

• 批准号: 355677-2009
• 负责人: Ouellet, François
• 金额: $ 1.82万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=431709
• 关键词: Environmental; hormonal; control; shoot; branching

Plant architecture is highly dependent on the pattern of shoot branching. From an agronomical perspective, the degree of branching is important because it affects the biomass and number of flowers (hence seeds), and in cultivated species it ultimately affects crop yield. Branching is controlled by environmental (e.g. temperature, water availability, photoperiod) and endogenous (hormones and other growth regulators) factors. The plant hormone auxin, which has been studied for decades, is considered the master regulator of branching. Recently, novel growth regulators called strigolactones have been identified. Both auxin and strigolactones are negative signals, meaning that they prevent the growth of lateral buds located on the stem, hence reducing shoot branching. A third class of growth regulators, cytokinins, act as positive regulators and promote branching. It is the ratio between the various hormones that determines if branching will occur. Environmental conditions influence branching, likely because they affect the levels of the different hormones. Our proposed research program aims to determine the underlying molecular mechanisms by which environmental factors influence the hormone-dependent signal transduction pathways that regulate shoot branching in the model plant Arabidopsis thaliana. We will use wild-type and mutant plants that show different levels of branching to determine which of the proteins from three families known to be involved in auxin responses are associated specifically with shoot branching. We will identify and characterize other candidate proteins associated with branching, such as regulators of gene expression. The proposed research program will therefore allow us to identify novel branching-associated proteins and determine how the environmental cues interact with endogenous signals to influence this very important physiological process. The knowledge gained will contribute to our understanding of plant growth determinants and will lead to the development of novel tools to improve plant performance and yield.

植物的构型高度依赖于枝条的模式。从农学的角度来看，分枝的程度很重要，因为它影响生物量和花朵的数量(即种子)，而在栽培物种中，它最终影响作物产量。分枝受环境(如温度、水分供应、光周期)和内源(激素和其他生长调节剂)因素的控制。植物激素生长素已被研究了几十年，被认为是分枝的主要调节因子。最近，人们发现了一种新的生长调节剂，称为三羟甲内酯。生长素和内酯都是负面信号，这意味着它们阻止了位于茎上的侧芽的生长，从而减少了枝条的分枝。第三类生长调节剂，细胞分裂素，作为积极的调节剂，促进分枝生长。正是各种激素之间的比例决定了是否会发生分支。环境条件影响分枝，可能是因为它们影响不同荷尔蒙的水平。我们提出的研究计划旨在确定环境因素影响激素依赖的信号转导途径的潜在分子机制，这些信号转导途径调控模式植物拟南芥的枝条分枝。我们将使用野生型和突变型植物，这些植物表现出不同的分枝水平，以确定已知的三个家族中与生长素反应有关的蛋白质中，哪些与枝条分枝有关。我们将识别和表征与分支相关的其他候选蛋白质，例如基因表达的调节。因此，拟议的研究计划将使我们能够识别新的分支相关蛋白，并确定环境信号如何与内源信号相互作用来影响这一非常重要的生理过程。所获得的知识将有助于我们理解植物生长决定因素，并将导致开发新的工具来改善植物表现和产量。