Molecular factors affecting plant architecture

植物的所有地上组织都是由存在于茎尖的少量干细胞或茎尖分生组织形成的。当这些细胞分裂时，它们被从它们的起源中心区推到外周区，在那里它们遇到不同的分子环境，并被诱导进行分化。这取决于在植物生命周期中发生的时间和地点，一个侧面器官被精心设计，采取花、叶或茎的形式。我们现在知道了一些控制干细胞增殖和分化的分子成分，我们对花、叶和根的发育也有了很多了解。明显缺乏的是对干细胞发育的描述。几年前，我的实验室开始了这样一个项目，选择专注于模式植物拟南芥（Arabidopsis thaliana）的短花梗（bp）突变体。这种突变体表现出许多发育缺陷。这是一个半矮子，我们已经表明，细胞分裂的过程受到损害。该突变体还表现出两种不同类型的“弯曲”：一种在茎枝点，另一种在花枝点。此外，支撑花的短茎，花梗，非常短（因此被称为突变体）。BP基因编码一种调节因子，许多证据表明，它有助于促进生长能力状态，因此，在缺乏它的情况下，生长和分化受到损害。我的实验室在理解茎和花梗发育方面取得了重大进展，提出的研究旨在进一步了解BP如何调节（以及受）控制形态发生的其他基因的调节。我们将使用一系列遗传、分子、生化和细胞学工具来识别相互作用的伙伴，并剖析介导BP作用的生化和信号转导途径。这些研究将巩固我们对植物结构如何在细胞和分子水平上被指定的理解，并可能用于考虑对具有农艺价值的植物进行定向改变，例如提高它们的生产力。这项研究为培养一批科学家提供了机会，使他们为从事基础研究和应用研究做好准备。

All aerial tissues of plants are derived from a small number of stem cells present at the apex, or shoot apical meristem. As these cells divide, they are pushed away from their origin, the central zone, into the peripherial zone, where they encounter a different molecular environment and are induced to undergo differentiation. Depending on when and where this occurs during the plant life cycle a lateral organ is elaborated, taking the form of a flower, a leaf, or a stem. We now know some of the molecular components that govern stem cell proliferation and differentiation and we know quite a lot about floral, leaf and root development. What has been conspicuously lacking is a description of stem development.  Several years ago my laboratory embarked on such a project, choosing to focus on the brevipedicellus (bp) mutant of the model plant Arabidopsis thaliana.  This mutant exhibits a number of developmental defects. It is a semi-dwarf and we have shown that the process of cell division is compromised. The mutant also exhibits two distinct types of 'bends': one at stem branch points, and the other at floral branch points. In addition, the short stem that supports the flower, the pedicel, is very short (hence the mutant moniker). The BP gene encodes a regulatory factor, and many lines of evidence suggest that it serves to promote a growth competent state, such that in its absence, growth and differentiation are compromised.My laboratory has made significant inroads towards understanding stem and pedicel development, and the proposed research is aimed at furthering our knowledge of how BP regulates (and is regulated by) other genes that control morphogenesis.  We will use a battery of genetic, molecular, biochemical and cytological tools to identify interacting partners and dissect the biochemical and signal transduction pathways that mediate BP action. These studies will solidify our understanding of how plant architecture is specified at the cellular and molecular levels, and may be used to contemplate directed changes to plants of agronomic value such as to increase their productivity. This research affords the opportunity to train a number of scientists, preparing them for careers in basic and applied research.