Osmoprotection of Pseudomonas Syringae During its Association with Plants: Role of the BetT and OpuC Transporters

丁香假单胞菌与植物结合过程中的渗透保护：BetT 和 OpuC 转运蛋白的作用

• 批准号: 0524300
• 负责人: Gwyn Beattie
• 金额: $ 39万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-15 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0524300&HistoricalAwards=false
• 关键词: Osmoprotection; Pseudomonas; Syringae; During; its

To cope with fluctuating osmolarity in their environment, microorganisms often produce transporters for the uptake of osmoprotectant compounds. These compounds, including glycine betaine and its precursor choline, occur widely in plants; however, little is known of their availability to the plant microflora. Osmoadaptation via transporter-mediated uptake may be important to the ecology of plant-associated bacteria based on the large fluctuations in water availability in microbial habitats on plants and the likely presence of plant-derived osmoprotectants. Understanding the role of these compounds in bacterial ecology requires knowledge of the transporters that mediate uptake. Two transporters that are responsible for all, or the vast majority, of the uptake of glycine betaine and its precursor choline under hyperosmotic stress have been identified in Pseudomonas syringae. This organism is a foliar pathogen, a common plant resident, and a model organism for studying bacterial-plant interactions. The goal of this project is to characterize these two transporters, designated BetT and OpuC, and evaluate their role in the osmoadaptation, growth and survival of P. syringae in plants. To address this goal, the functional characteristics of BetT and OpuC, including their kinetic parameters and solute specificity, will be characterized, their regulation at the transcriptional and post-transcriptional levels will be examined, and their significance to P. syringae ecology on plants that have various natural and manipulated concentrations of osmoprotectants will be identified. This information will help fill a void of information on uptake-mediated osmoadaptation in Pseudomonas species and will provide insights into how bacteria so expertly exploit the ecological niches to which they are adapted. The knowledge generated in these studies is relevant to improving food safety and production, including strategies for controlling plant and animal pathogens on plants, improving plant disease forecasting and control, and predicting non-target effects of transgenic plants engineered for enhanced tolerance to drought and salinity stress. This project will contribute to education through training a postdoctoral researcher, a graduate student, and four undergraduate students, at least one of which is expected to be a minority student; outreach activities for secondary school students and international agricultural scientists; and curriculum strengthening activities for an undergraduate microbiology program.

为了应对环境中渗透压的波动，微生物通常会产生转运蛋白来吸收渗透保护化合物。这些化合物，包括甘氨酸甜菜碱及其前体胆碱，广泛存在于植物中；然而，人们对它们对植物微生物区系的可用性知之甚少。基于植物上微生物栖息地的水可用性的巨大波动以及植物来源的渗透保护剂的可能存在，通过转运蛋白介导的吸收进行的渗透适应可能对植物相关细菌的生态学很重要。了解这些化合物在细菌生态学中的作用需要了解介导吸收的转运蛋白。已在丁香假单胞菌中鉴定出两种转运蛋白，它们负责高渗胁迫下甘氨酸甜菜碱及其前体胆碱的全部或绝大多数吸收。这种生物是一种叶病原体，是一种常见的植物居民，也是研究细菌与植物相互作用的模式生物。该项目的目标是表征这两种转运蛋白（指定为 BetT 和 OpuC），并评估它们在植物中丁香假单胞菌的渗透适应、生长和存活中的作用。为了实现这一目标，将表征 BetT 和 OpuC 的功能特征，包括它们的动力学参数和溶质特异性，将检查它们在转录和转录后水平的调节，并确定它们对具有各种天然和操纵浓度的渗透保护剂的植物的丁香假单胞菌生态学的意义。这些信息将有助于填补假单胞菌属物种中吸收介导的渗透适应的信息空白，并将提供有关细菌如何如此熟练地利用它们所适应的生态位的见解。这些研究中产生的知识与改善食品安全和生产相关，包括控制植物上的植物和动物病原体的策略、改善植物病害的预测和控制，以及预测转基因植物的非目标效应，以增强对干旱和盐胁迫的耐受性。该项目将通过培训一名博士后研究员、一名研究生和四名本科生（其中至少一名预计为少数民族学生）为教育做出贡献；针对中学生和国际农业科学家的外展活动；本科微生物学课程的课程强化活动。