Developmental Asymmetry in Agrobacterium tumefaciens

描述（由申请人提供）：许多细菌，包括根癌土壤杆菌，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。发育不对称性的研究在模式α-变形菌生物新月柄杆菌中进展良好，其中互连的PleC/DivJ-DivK和CckA-ChpT-CtrA/CpdR His-Asp磷酸中继起着核心作用。尽管包括A.对于这些调节蛋白在这些其它生物体中的确切作用知之甚少。两种相关的蛋白质，PleC-DivJ同源传感器激酶PdhS 1和PdhS 2，仅限于α-变形菌的一个子集，其经常与真核宿主共生或致病关系。本研究探讨了这些调节蛋白在A.根瘤菌特别地，本申请解决了PdhS 1和PdhS 2如何有助于A的形态学、生理学和时间发育。以及这些过程是否有助于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进行。PdhS 1和PdhS 2都将进行生物化学解剖，以确定个人的催化和监管结构域的贡献，他们的活动，并确定潜在的相互作用的合作伙伴。A.根癌农杆菌以极性方向结合到非生物和生物表面，并且已知其精心制作极性鞭毛、皮利和IV型分泌系统。此外，A.根癌农杆菌和许多其它α-变形菌通过不对称的出芽过程进行分裂，从附着的非运动形式发展到形态上不同的运动形式。表型分析将评估PdhS 1和PdhS 2对极性发育、运动性、生物膜形成和毒力的贡献。其他基因和调控相互作用的影响协调极性形态发生，运动，生物膜形成在A。将使用转座子诱变和新的高通量显微镜筛选的组合来鉴定根癌农杆菌。

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.