Function of Arabidopsis thaliana Proline Rich Proteins in Root Hairs and Guard Cells of Arabidopsis

拟南芥富含脯氨酸蛋白在拟南芥根毛和保卫细胞中的功能

• 批准号: 0213437
• 负责人: Mary Tierney
• 金额: $ 36万
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2005-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0213437&HistoricalAwards=false
• 关键词: Function; Arabidopsis; thaliana; Proline; Rich

The plant cell wall is a dynamic structure that can be modified in responseto developmental and environmental signals. In this manner, the cell wallprovides structural information that helps maintain cellular form andfunction during plant growth. The structure of the cell wall also changesin response to pathogen infection and stresses, such as drought, high saltand cold temperature, in a manner that helps protect plants from biotic andabiotic stresses when grown in natural environments. Expression of many ofthe structural proteins in the wall have been shown to be cell-typespecific, suggesting that these proteins play novel roles in modifying cellwall structure in order to provide mechanical strength and assist in properwall assembly.Proline-rich proteins (PRPs) represent an integral family of structuralcell wall proteins whose expression has been linked to active growth in anumber of plant systems. We have used a combination of PRP promoter/GUSfusions and epitope-tagging to characterize the expression of these genesin arabidopsis and their localization to the walls of specific cell types.Two of these proteins, AtPRP1 and AtPRP3, are expressed during the earlystages of root hair outgrowth but are localized within different regions ofthe root hair cell wall. These results suggest that individual PRP genefamily members may play distinct roles in helping to establish root haircell wall structure during wall assembly. In addition, we have shown thatAtPRP4 is expressed in guard cells and localizes to the inner shelf of theguard cell wall. We have isolated several T-DNA insertion alleles forthese three proteins and we propose to characterize the loss-of-functionphenotypes in these mutants associated with root hair and guard cellfunction. In addition, we will examine the ability of epitope-tagged PRPsequences to become cross-linked within the wall in wild type and mutantPRP backgrounds. In combination, these experimental approaches shouldprovide new insight into the nature of the amino acid sequences encodedwithin individual AtPRPs that are sufficient for their targetedlocalization within the cell wall and their insolubilization within theextracellular matrix.Identification of the function of structural cell wall proteins in definingcell-type specific matrix structures is an important first step in ourability to modify the cell walls of plants in a manner that will let themgrow in adverse environments. We have shown that the AtPRP proteinsparticipate in determining cell wall structure in guard cells and roothairs, two cell types that are crucial for nutrient uptake and maintenanceof water balance during growth. Further analysis of the function of theseproteins may allow us to devise novel mechanisms for enhancing plant growthunder conditions of water and/or nutrient limitation.

植物细胞壁是一种动态的结构，可以响应发育和环境信号进行修饰。 以这种方式，细胞壁提供结构信息，帮助维持植物生长过程中的细胞形态和功能。 细胞壁的结构也会随着病原体感染和干旱、高盐和低温等胁迫而发生变化，这种变化有助于保护植物在自然环境中生长时免受生物和非生物胁迫。 许多结构蛋白在细胞壁中的表达具有细胞类型特异性，这表明这些蛋白质在改变细胞壁结构以提供机械强度和帮助正确的细胞壁组装方面发挥着新的作用。富含脯氨酸蛋白（PRPs）是结构细胞壁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。 我们使用PRP启动子/GUS融合和表位标记的组合来表征这些基因在拟南芥中的表达及其在特定细胞类型壁的定位。其中两种蛋白质AtPRP 1和AtPRP 3在根毛生长的早期阶段表达，但定位在根毛细胞壁的不同区域内。 这些结果表明，个别PRP genefamily成员可能发挥不同的作用，在帮助建立根毛细胞壁结构在壁组装。 此外，我们已经证明AtPRP 4在保卫细胞中表达，并定位于保卫细胞壁的内层。 我们已经分离出几个T-DNA插入等位基因forthese三种蛋白质，我们建议在这些突变体的功能丧失的表型与根毛和保卫细胞功能的特点。 此外，我们将研究表位标记的PRP序列的能力，成为在野生型和mu型PRP背景的墙壁内交联。 结合起来，这些实验方法应该提供新的见解编码的氨基酸序列的性质，在个别AtPRPs是足够的，为他们的靶向定位在细胞壁和他们的不溶性在细胞外基质。类型特异性基质结构是以使植物在不利环境中生长的方式改变植物细胞壁的可行性的重要的第一步。 我们已经证明AtPRP蛋白参与决定保卫细胞和根毛的细胞壁结构，这两种细胞类型对生长期间营养吸收和维持水分平衡至关重要。 对这些蛋白功能的进一步分析可能使我们能够设计出在水分和/或养分限制条件下促进植物生长的新机制。