Physiology and Genetics of Phosphorus Metabolism in Rhizobium

9413485麦克德莫特：这是美国国家科学基金会植物生物学博士后研究员的初步拨款。本研究的长期目标是了解磷(P)在根瘤菌-豆科植物共生中的作用。该研究计划分为三个总体目标，旨在从博士后研究停止的地方继续进行。第一个目标是确定在共生过程中影响细菌磷供应或细菌磷获取活动的因素。这包括确定宿主基因或生长阶段在多大程度上可以影响细菌磷的供应，以及根瘤生态的各个方面是否会影响细菌调控机制。第二个目标涉及研究在共生过程中各种可能的磷来源的重要性。这将通过分离在不同的磷获取机制中存在缺陷的根瘤菌突变株来实现，并测试它们的共生表型。第三个目标是开始克隆与磷代谢调节有关的基因，以便我们能够开始了解环境磷如何以及在多大程度上影响共生的各个方面。上述研究是了解(Brady)根瘤菌磷代谢的一次全面和有针对性的尝试。它融合了生理学、分子生物学和生物化学，应该能迅速提供有关大量营养素的重要信息，而在世界范围内，这种重要的经济共生是已知的限制因素。***

9413485 McDermott This is a starter grant for an NSF Postdoctoral Research Fellow in Plant Biology. The long-term objective of the research is to understand the role of phosphorus (P) in the Rhizobium-legume symbiosis. The research plan is divided into three general goals, and is designed to carry on from where the postdoctoral research stopped. The first goal is to determine what factors influence bacteroid P supply or bacteriod P acquisition activities during symbiosis. This includes determining to what extent host genotype or growth stage can influence bacteroid P supply and if aspects of nodule ecology can affect bacteroid regulatory mechanisms. The second goal involves looking at the importance of various possible sources of P during symbiosis. This will be achieved by isolating Rhizobium mutants with defects in the different mechanisms of P acquisition, and testing them for a symbiosis phenotype. The third goal is to begin cloning the genes involved in P metabolic regulation so that we can begin to understand how and to what extent enviornmental P can influence all aspects of symbiosis. The above research represents a comprehensive and directed attempt at understanding P metabolism in (Brady)Rhizobium. It blends physiology, molecular biology, and biochemistry in a way that should quickly provide important information about a macronutrient that, on a world-wide basis, is known to be limiting for this ecomonically important symbiosis. ***