Role of ATPRPs in Determining Root Hair and Guard Cell Wall Structure

智力优势：植物细胞壁是动态的，可以根据发育和环境信号进行修改。通过这种方式，细胞壁提供结构信息，帮助维持植物生长期间的细胞形态和功能。细胞壁中许多结构蛋白的表达已被证明具有细胞类型特异性，这表明这些蛋白可能在修饰细胞壁结构方面发挥新的作用，以提供机械强度并协助正确的细胞壁组装。脯氨酸富蛋白（PRPs）是细胞壁结构蛋白的一个完整家族，其表达与许多植物系统的活性生长有关。其中两种蛋白，AtPRP1和AtPRP3，在拟南芥根毛生长的早期阶段表达，但定位于根毛细胞壁的不同区域。这些结果表明，PRP基因家族成员在根毛细胞壁组装过程中可能在帮助建立细胞壁结构方面发挥了不同的作用。此外，该基因家族的另外两个成员AtPRP2和AtPRP4在保护细胞中表达，分别定位于保护细胞壁的内壁和空气空间周围的壁。这些研究将描述与根毛和保护细胞功能相关的突变体的功能丧失表型。此外，研究者将检测表位标记的PRP序列在野生型和突变型PRP背景下的功能。综上所述，这些实验方法将为这些蛋白质的功能、单个AtPRPs编码的氨基酸序列的性质以及它们在细胞壁内的靶向定位和细胞外基质内的不溶性提供新的见解。更广泛的影响：结构细胞壁蛋白在植物发育过程中参与维持细胞的形状和功能。然而，这些蛋白质在不同细胞类型中以独特的方式参与植物细胞外基质结构建模的机制尚不清楚。本研究的结果将为了解富含脯氨酸的蛋白在细胞壁内的功能所需的初级序列，以及PRPs定向分泌到保卫细胞和根毛生长的细胞机制提供新的认识。从长远来看，这些信息可能允许研究人员定制植物细胞外基质结构，以支持在不利环境条件下生长的植物的细胞功能。本提案提供的资金也将用于支持本科生和研究生的参与。参与本研究的学生将在国内和国际会议上报告他们的实验结果。

Intellectual Merit: The plant cell wall is dynamic and can be modified in response to developmental and environmental signals. In this manner, the cell wall provides structural information that helps maintain cellular form and function during plant growth. Expression of many of the structural proteins in the wall have been shown to be cell-type specific, suggesting that these proteins may play novel roles in modifying cell wall structure in order to provide mechanical strength and assist in proper wall assembly. Proline-rich proteins (PRPs) represent an integral family of structural cell wall proteins whose expression has been linked to active growth in a number of plant systems. Two of these proteins, AtPRP1 and AtPRP3, are expressed during the early stages of root hair outgrowth in Arabidopsis but are localized within different regions of the root hair cell wall. These results suggest that individual PRP gene family members may play distinct roles in helping to establish root hair cell wall structure during wall assembly. In addition, two other members of this gene family, AtPRP2 and AtPRP4, are expressed in guard cells and localize to the inner shelf and the wall surrounding the air space, respectively, of the guard cell wall. These studies will characterize the loss-of-function phenotypes in mutants associated with root hair and guard cell function. In addition, the investigator will examine the function of epitope-tagged PRP sequences in wildtype and mutant PRP backgrounds. In combination, these experimental approaches should provide new insight into the function of these proteins, the nature of the amino acid sequences encoded within individual AtPRPs that are sufficient for their targeted localization within the cell wall, and their insolubilization within the extracellular matrix.Broader Impacts: Structural cell wall proteins have been implicated in maintaining cell shape and function during plant development. However, the mechanism(s) through which these proteins participate in modeling the structure of plant extracellular matrices in unique ways within different cell types is poorly understood. Results from the proposed research will provide new understanding of the primary sequences required for proline-rich protein function within the cell wall as well as cellular mechanisms responsible for the targeted secretion of PRPs to the growing walls of guard cells and root hairs in Arabidopsis. Long-term, this information may allow investigators to tailor plant extracellular matrix structure to support cell function of plants grown under adverse environmental conditions.Funds provided by this proposal will also be used to support undergraduate and graduate student participation. Students involved in this research will report their experimental findings at national and international meetings.