Metabolic multitasking: How Ralstonia solanacearum uses nitrate for plant pathogenesis

致病菌拉斯顿菌（Ralstonia solanacearum）在植物寄主的维管组织中非常成功，即使这个栖息地含有很少的营养和氧气。这个项目的核心假设是，R. solanacearum利用无机氮（植物汁液中为数不多的丰富营养物质之一）不仅作为食物，而且还产生能量，感知和操纵植物防御。研究人员将使用遗传和生化实验来确定这种病原体在引起植物疾病时以多种方式利用无机氮的特定适应性。预期的结果包括更好地理解R. solanacearum如何在低氧水平下生长，以及对一氧化氮（一种常见的生物信号分子，也具有抗菌特性）毒力的作用的定义。茄枯菌是一种分布广泛、寄主众多的病原菌，因此这些结果可能与多种植物相关微生物有关。植物维管系统是许多微生物的家园，从具有破坏性的病原体，如番茄红霉，到有价值的共生菌，可以提高植物的抗逆性或生长。该项目将产生关于植物微生物使用的生化机制的基本生物学知识。此外，该项目将培养一名博士后研究员和一名博士生，在实验室研究、教学和指导方面为国家的科学劳动力做出贡献，这些都是未来教师的关键技能。三名本科生也将获得独立的微生物学研究经验。

The pathogenic bacterium Ralstonia solanacearum is very successful in the vascular tissue of its plant hosts even though this habitat contains few nutrients and little oxygen. This project's central hypothesis is that R. solanacearum uses inorganic nitrogen, one of the few abundant nutrients in plant sap, not just for food but also to generate energy and to sense and manipulate plant defenses. The investigators will use genetic and biochemical experiments to identify the specific adaptations that allow this pathogen to use inorganic nitrogen in multiple ways as it causes plant disease. Expected results include a better understanding of how R. solanacearum grows at low oxygen levels and a definition of the role(s) in virulence of nitric oxide, a common biological signal molecule that also has antimicrobial properties. R. solanacearum is a widely distributed pathogen with many hosts, so these results are likely to be relevant to diverse plant-associated microbes. Plant vascular systems are home to many microbes, ranging from destructive pathogens like R. solanacearum to valuable mutualists that can increase plant stress tolerance or growth.This project will generate basic biological knowledge about the biochemical mechanisms used by plant-inhabiting microbes. In addition, this project will contribute to the nation's scientific workforce by training a postdoctoral researcher and a doctoral student in laboratory research, teaching and mentoring, which are all key skills for future faculty. Three undergraduate students will also receive independent research experiences in microbiology.