Gamma‐proteobacteria Xanthomonas spp. cause at least 350 different plant diseases among important agricultural crops, which result in serious yield losses. Xanthomonas spp. rely mainly on the type III secretion system (T3SS) to infect their hosts and induce a hypersensitive response in nonhosts. HrpG, the master regulator of the T3SS, plays the dominant role in bacterial virulence. In this study, we used chromatin immunoprecipitation followed by sequencing (ChIP‐seq) and tandem affinity purification (TAP) to systematically characterize the HrpG regulon and HrpG interacting proteins in vivo. We obtained 186 candidate HrpG downstream genes from the ChIP‐seq analysis, which represented the genomic‐wide regulon spectrum. A consensus HrpG‐binding motif was obtained and three T3SS genes, hpa2, hrcU, and hrpE, were confirmed to be directly transcriptionally activated by HrpG in the inducing medium. A total of 273 putative HrpG interacting proteins were identified from the TAP data and the DNA‐binding histone‐like HU protein of Xanthomonas campestris pv. campestris (HU_xcc) was proved to be involved in bacterial virulence by increasing the complexity and intelligence of the bacterial signalling pathways in the T3SS.

中文翻译：

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利用ChIP-seq和亲和蛋白质组学分析喜多单胞菌（Xanthomonas campestris）中的HrpG调节子和HrpG相互作用蛋白。

γ-变形杆菌Xanthomonas spp。在重要的农作物中至少引起350种不同的植物病害，导致严重的单产损失。黄单胞菌属。主要依靠III型分泌系统（T3SS）感染其宿主并在非宿主中诱发超敏反应。HrpG是T3SS的主要调控因子，在细菌毒力中起主要作用。在这项研究中，我们使用了染色质免疫沉淀，然后进行测序（ChIP-seq）和串联亲和纯化（TAP）来系统表征体内HrpG调节子和HrpG相互作用蛋白。我们从ChIP-seq分析中获得了186个候选HrpG下游基因，这些基因代表了全基因组的调节子谱。获得了共有的HrpG结合基序和三个T3SS基因，已证实hpa2，hrcU和hrpE在诱导培养基中被HrpG直接转录激活。根据TAP数据和Xanthomonas campestris pv的DNA结合组蛋白样HU蛋白，共鉴定出273种HrpG相互作用蛋白。油菜（HU _XCC）证明通过在T3SS增加细菌信号传导途径的复杂性和智能在细菌毒力的参与。