Dow Max
BIOMERIT Research Centre, Department of Microbiology, BioSciences Institute, National University of Ireland, Cork, Ireland.
Sci Signal. 2008 May 27;1(21):pe23. doi: 10.1126/stke.121pe23.
The virulence of plant pathogenic bacteria belonging to the genera Xanthomonas and Xylella depends upon cell-to-cell signaling mediated by the diffusible signal molecule DSF (Diffusible Signaling Factor). Synthesis and perception of the DSF signal require products of the rpf gene cluster. The synthesis of DSF depends on RpfF, whereas the RpfC/RpfG two-component system is implicated in DSF perception and signal transduction. The sensor RpfC acts to negatively regulate synthesis of DSF. In Xanthomonas campestris, mutation of rpfF or rpfC leads to a coordinate down-regulation in synthesis of virulence factors and a reduction in virulence. In contrast, in Xylella fastidiosa, the causal agent of Pierce's disease of grape, mutation of rpfF and rpfC have opposite effects on virulence, with rpfF mutants exhibiting a hypervirulent phenotype. The findings suggest that different xanthomonads have adapted the perception and function of similar types of signaling molecule to fit the specific needs for colonization of different hosts.
属于黄单胞菌属和木质部小菌属的植物致病细菌的毒力取决于由可扩散信号分子DSF（可扩散信号因子）介导的细胞间信号传导。DSF信号的合成和感知需要rpf基因簇的产物。DSF的合成取决于RpfF，而RpfC/RpfG双组分系统与DSF感知和信号转导有关。传感器RpfC起到负调节DSF合成的作用。在野油菜黄单胞菌中，rpfF或rpfC的突变导致毒力因子合成的协同下调和毒力降低。相反，在葡萄皮尔氏病的病原菌葡萄木质部难养菌中，rpfF和rpfC的突变对毒力有相反的影响，rpfF突变体表现出超毒力表型。这些发现表明，不同的黄单胞菌已经适应了相似类型信号分子的感知和功能，以满足不同宿主定殖的特定需求。
