CAREER: Chemosensory Behavior in Plant-Microbe Association

促进植物生长的固氮细菌Azospirillum brasilense在植物根表面的定植可能依赖于对根渗出物的趋化性。然而，在大多数植物相关细菌中，控制化学感觉行为的分子机制仍然知之甚少。本课题主要研究巴西芽孢杆菌化学感觉行为的分子基础及其在小麦根系定殖中的作用。首先，将阐明中心趋化调节因子CheA的独特保守结构域在感知和行为中的功能（研究目标1）。接下来，将确定新的化学感受器在行为中的功能（研究目标2）。最后，将确定一般趋化机制和个体趋化受体在偶氮螺旋藻-小麦关联建立中的贡献（研究目标3）。本研究的结果将增强对原核生物信号转导多样性的理解，并直接有利于生物肥料设计领域。所获得的结果可用于培养具有更好定殖能力的菌株，以在重要的农艺植物（如小麦）的根际定殖。细菌的感知和行为非常适合拓宽大学生的教育经验，并为K-12学生开发基于研究的教育材料。正在进行的项目将为本科生（教育目标1）和K-12科学教师（教育目标2）提供研究机会。一个关于“微生物感知”的模块将在美国国家科学基金会资助的生物巴士项目中实施，该项目为格鲁吉亚的K-12学生提供基于探究的学习机会和动手实验（教育目标3）。

The colonization of the plant root surface by the plant-growth promoting nitrogen-fixing bacterium Azospirillum brasilense is likely to be dependent on chemotaxis toward root exudates. However, the molecular mechanisms governing chemosensory behavior in most plant-associated bacteria are still poorly understood. This research project focuses on establishing the molecular basis of the chemosensory behavior in A. brasilense and its role in wheat root colonization. First, the function of the unique conserved domain of the central chemotaxis regulator CheA in sensing and behavior will be elucidated (research objective 1). Next, the function of novel chemoreceptors in behavior will be identified (research objective 2). Finally, the contribution of the general chemotaxis machinery and individual chemoreceptors in the establishment of the Azospirillum-wheat association will be determined (research objective 3). The outcome of the proposed research will enhance understanding of diversity in signal transduction in prokaryotes and directly benefit the field of biofertilizer design. The results obtained can be used for developing strains with improved abilities to colonize the rhizosphere of agronomically important plants, such as wheat. Sensing and behavior in bacteria are uniquely suited for broadening the educational experience of college students and enable the development of research-based educational materials for K-12 students. Undergraduate students (education objective 1) and K-12 science teachers (education objective 2) will be provided with research opportunities in the ongoing project. A module on "Microbial Sensing" will be implemented in the NSF-funded Bio-Bus project that provides inquiry-based learning opportunities and hands-on experiments to Georgia's K-12 students (education objective 3).