Regulation of Root and Nodule Meristems By The LATD Gene and the Hormone Abscisic Acid in the Model Legume, Medicago Truncatula

与动物的情况不同，大部分植物的发育不是发生在胚胎中，而是在种子萌发后并持续到植物的整个生命周期。所有新的生长最初都来自于茎和根顶端的一个特殊区域，称为分生组织。在阐述了主根之后，植物的根系以两种方式扩大：第一，长得更长，第二，形成从主根开始生长的分支根，称为侧根。此外，植物的根不是随机形成的，而是对环境和内在因素的差异做出反应，如协调植物反应的化学信使或激素。本研究探讨了一种植物激素脱落酸(ABA)对初生根和侧根分生组织生长的影响。豆科植物的根形成一种额外的结构，即共生根瘤，这是与有益细菌根瘤相互作用的结果。这些根瘤的进化起源尚不清楚，但它们似乎与侧根有一些共同的特征。本项目将研究在豆科植物侧根和根瘤中的ABA反应中，Mtruncatula LATD基因的作用。该项目的目的是克隆和测序LATD基因，并确定其在豆科植物根和根瘤的ABA反应中的作用。这些发现将有助于加深对植物对共生根瘤的控制、豆类植物中的激素信号以及根瘤形成与根系生长的关系的了解。广泛的影响：豆类是世界粮食供应的重要组成部分。这个项目将研究豆类植物的根系形成与其他植物的不同之处，并可能导致改进农业实践。它还将帮助培训一名博士后、研究生和本科生研究人员，以及继续与当地一所小学开展外联活动，涉及以植物为基础的关于根生长的科学实验，并根据他们的实验进行预测。

Unlike the situation seen in animals, much of plant development does not occur in the embryo, but rather, after the seed germinates and continues for the lifetime of the plant. All new growth initially is derived from a special region at the tip of the shoot and root called the meristem. Following elaboration of the primary root, plant root systems enlarge in two ways: first, by growing longer, and second, by forming branch roots, called lateral roots, which grow from the main root. Furthermore, plant roots do not form randomly, but are responsive to differences in the environment and intrinsic factors such as the chemical messengers, or hormones, that coordinate the plant's response. This study examines the effect of a plant hormone, Abscisic Acid (ABA), on the growth of meristems of both primary and lateral roots. Legume roots form an additional structure, a symbiotic root nodule, that results from an interaction with a beneficial bacterium, Rhizobium. The evolutionary origin of these nodules is unknown, but they appear to share some features with lateral roots. This project will examine the role of the M. truncatula LATD gene in the ABA response both in legume lateral roots and in nodules. The aims of the project are to clone and sequence the LATD gene and to determine its role in the ABA response of legume roots and nodules. These findings will lead to increased understanding of plant control of symbiotic nodules, hormone signaling in legumes, and the relationship of nodule formation to growth of the root system.Broader Impacts: Legumes are an important part of the world's food supply. This project will examine how root system formation in legumes differs from that of other plants and may lead to improved agricultural practices. It will also contribute to the training of a postdoc, graduate student, and undergraduate researchers, as well as continuing outreach activities with a local elementary school, involving plant-based science experiments on root growth and the development of predictions based upon their experiments.