Developmental Asymmetry in Agrobacterium tumefaciens

描述（由申请人提供）：许多细菌，包括农杆菌，在与潜在宿主及其环境相互作用时，依赖于特定附属物的不对称定位、分布和方向。在模式a-变形细菌有机体新月形Caulobacter crescentus中，对发育不对称的研究进展良好，其中相互连接的PleC/DivJ-DivK和CckA-ChpT-CtrA/CpdR His-Asp磷接力发挥核心作用。尽管a-变形菌门（包括a-变形杆菌）高度保守，但人们对这些调节蛋白在其他生物中的确切作用知之甚少。plc - divj同系物传感器激酶PdhS1和PdhS2这两种相关蛋白仅局限于a-变形菌的一个子集，它们经常以共生或致病关系与真核宿主相关联。本研究探讨了这些调节蛋白在瘤胃芽胞杆菌中的作用。特别地，本应用程序研究了PdhS1和PdhS2如何促进农杆菌的形态、生理和时间发育，以及这些过程是否有助于在宿主和非宿主生态位之间的过渡。这将使用遗传，生化和细胞学分析的组合来执行。将对PdhS1和PdhS2进行生化剖析，以确定个体催化和调控结构域对其活性的贡献，并确定潜在的相互作用伙伴。结核菌以极性方向与非生物和生物表面结合，并具有极鞭毛、毛和IV型分泌系统。此外，a . tummefaciens和许多其他a-变形杆菌通过不对称的出芽过程进行分裂，从附着的非运动形式到形态上不同的运动形式。表型分析将评估PdhS1和PdhS2对极性发育、运动、生物膜形成和毒力的贡献。利用转座子诱变和新型高通量显微镜筛选技术，研究人员将鉴定出影响瘤胃芽孢杆菌极性形态发生、运动和生物膜形成协调的其他基因和调控相互作用。

DESCRIPTION (provided by applicant): Many bacteria, including Agrobacterium tumefaciens, rely on an asymmetric localization, distribution, and orientation of specific appendages when interacting with potential hosts and with their environment. The study of developmental asymmetry is well advanced in the model a-Proteobacterial organism Caulobacter crescentus where the interlinked PleC/DivJ-DivK and CckA-ChpT-CtrA/CpdR His-Asp phosphorelays play a central role. Despite a high degree of conservation among the a-Proteobacteria, including A. tumefaciens little is known about the precise role of these regulatory proteins in these other organisms. Two related proteins, the PleC-DivJ homologue sensor kinases PdhS1 and PdhS2, are restricted to a subset of a-Proteobacteria that frequently associate with a eukaryotic host in a symbiotic or pathogenic relationship. This study examines the role of these regulatory proteins in A. tumefaciens. In particular, this application addresses how PdhS1 and PdhS2 contribute to the morphological, physiological, and temporal development of A. tumefaciens and whether these processes contribute to the transition between host and non-host niches. This will be performed using a combination of genetic, biochemical, and cytological analyses. PdhS1 and PdhS2 will both be biochemically dissected to determine the contribution of individual catalytic and regulatory domains to their activity and to identify potential interacting partners. A. tumefaciens binds to abiotic and biotic surfaces in a polar orientation and is known to elaborate polar flagella, pili, and a type IV secretion system. In addition, A. tumefaciens and many other a-Proteobacteria divide by an asymmetric process of budding, proceeding through an attached, non-motile form to a morphologically distinct motile form. Phenotypic analysis will evaluate the contribution of PdhS1 and PdhS2 to polar development, motility, biofilm formation, and virulence. Additional genes and regulatory interactions that influence coordination of polar morphogenesis, motility, and biofilm formation in A. tumefaciens will be identified using a combination of transposon mutagenesis and a novel high-throughput microscopy screen.