Mechanisms of Rapid Alkalinization Factor Induced Growth Arrest in Arabidopsis

描述（由申请人提供）：是什么决定了多细胞生物体的形状和大小是生物学中的一个基本问题。植物提供了一个相对简单的系统来研究这个问题，因为它们的组织和细胞类型比动物少。本研究的目的是了解肽激素快速碱化因子（RALF）拮抗植物生长，特别是细胞伸长的分子机制。将外源RALF肽应用于生长中的幼苗会导致根和芽的生长停滞，并且RALF的系统过表达会导致半矮生植物。所有的植物基因组检测包含至少一个RALF肽编码基因，指出在植物生长的基本作用。RALF诱导生长停滞的分子细节目前尚不清楚，了解这种肽激素如何影响生长可以使植物生物学家操纵植物结构以改善作物。 在这个提议中概述的实验结合了联合收割机生理学、基因组学和遗传学方法来理解RALF在模式植物拟南芥中的功能。具体地说，实验的目的是了解RALF信号如何拮抗生长素和油菜素类固醇诱导的幼苗生长，并通过用RALF 1肽处理的幼苗进行微阵列实验来开发转录生长网络。基因筛选的目的是发现RALF诱导的生长停滞所需的基因。迄今为止描述的植物肽激素的受体是富含亮氨酸重复序列的受体样激酶（LRR-RLK），并且我们预期RALF肽受体也将是LRR-RLK。动物系统中的LRR-RLK在器官发育和免疫中发挥重要作用;因此，了解这些类型的受体如何发挥作用将具有广泛的影响。总之，这些实验将开始解开RALF作用的机制，并大大增加了目前的植物细胞生长模型。 公共卫生相关性：细胞通过信号分子相互沟通，以协调生长和代谢过程，而错误的沟通可能导致人类疾病，包括癌症和糖尿病。该提案旨在了解一种称为快速碱化因子的植物肽激素如何作为细胞间信号影响生长。了解细胞如何相互交流对于治疗许多疾病至关重要，从这些实验中获得的数据可以为健康相关研究提供新的见解。

DESCRIPTION (provided by applicant): What determines the shape and size of multicellular organisms is a fundamental question in biology. Plants offer a relatively simple system to study this question because they have fewer tissues and cell types than animals. The objective of this study is to understand the molecular mechanisms by which the peptide hormone Rapid Alkalinization Factor (RALF) antagonizes plant growth, specifically cell elongation. Application of exogenous RALF peptide to growing seedlings causes growth arrest of both roots and shoots, and systemic over-expression of RALF results in semi-dwarf plants. All plant genomes examined contain at least one RALF peptide-encoding gene, pointing to a fundamental role in plant growth. The molecular details of RALF-induced growth arrest are currently unknown, and understanding how this peptide hormone influences growth could allow plant biologists to manipulate plant architecture for the improvement of crops. The experiments outlined in this proposal combine physiological, genomic, and genetic approaches to understand RALF function in the model plant Arabidopsis thaliana. Specifically, the experiments are designed to understand how RALF signaling antagonizes auxin and brassinosteroid-induced growth in seedlings and to develop a transcriptional growth network by performing microarray experiments with seedlings treated with RALF1 peptide. Genetic screens have been designed to discover genes required for RALF-induced growth arrest. Receptors for plant peptide hormones described to date have been leucine rich repeat receptor-like kinases (LRR-RLKs), and we anticipate that a RALF peptide receptor would also be an LRR-RLK. LRR-RLKs in animal systems play important roles in organ development and immunity; therefore, understanding how these types of receptors function will have wide reaching implications. Together, these experiments will begin to unravel the mechanisms RALF action and add significantly to the current model of how plant cells grow. PUBLIC HEALTH RELEVANCE: Cells communicate with one another using signaling molecules to coordinate growth and metabolic processes, and miscommunication can result in disease states in humans including cancer and diabetes. This proposal aims to understand how a plant peptide hormone called Rapid Alkalinization Factor acts as a cell-to-cell signal to influence growth. Knowing how cells communicate with one another is vital to curing many diseases, and data gained from these experiments could provide new insights to apply to health related research.