Yan Yichao, Wang Yanyan, Yang Xiaofei, Fang Yuan, Cheng Guanyun, Zou Lifang, Chen Gongyou
Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
Microorganisms. 2022 Jul 31;10(8):1549. doi: 10.3390/microorganisms10081549.
pv. () causes bacterial leaf blight (BLB) in rice, which is one of the most severe bacterial diseases in rice in some Asian countries. The type III secretion system (T3SS) of encoded by the hypersensitive response and pathogenicity () genes is essential for its pathogenicity in host rice. Here, we identified the Min system (MinC, MinD, and MinE), a negative regulatory system for bacterial cell division encoded by , , and genes, which is involved in negative regulation of genes ( and ) in . We found that the deletion of , , and resulted in enhanced and expression, which is dependent on two key regulators HrpG and HrpX. The , , and mutants exhibited elongated cell lengths, and the classic Min system-defective cell morphology including minicells and short filamentations. Mutation of in resulted in significantly impaired virulence in host rice, swimming motility, and enhanced biofilm formation. Our transcriptome profiling also indicated some virulence genes were differentially expressed in the mutants. To our knowledge, this is the first report about the Min system participating in the regulation of T3SS expression. It sheds light on the understanding of virulence mechanisms.
稻黄单胞菌（Xanthomonas oryzae pv. oryzae）会引发水稻白叶枯病，这是亚洲一些国家水稻中最严重的细菌性病害之一。由过敏反应和致病性（hrp）基因编码的III型分泌系统（T3SS）对其在寄主水稻中的致病性至关重要。在此，我们鉴定了由minC、minD和minE基因编码的Min系统，这是一种细菌细胞分裂的负调控系统，参与对稻黄单胞菌中hrp基因（hrpA和hrpB）的负调控。我们发现，缺失minC、minD和minE会导致hrpA和hrpB表达增强，这依赖于两个关键的hrp调控因子HrpG和HrpX。minC、minD和minE突变体表现出细胞长度延长，以及包括微细胞和短丝化在内的典型Min系统缺陷型细胞形态。稻黄单胞菌中minE的突变导致其在寄主水稻中的毒力显著受损、游动性降低以及生物膜形成增强。我们的转录组分析还表明，一些毒力基因在minC、minD和minE突变体中差异表达。据我们所知，这是关于Min系统参与调控T3SS表达的首次报道。它为理解稻黄单胞菌的毒力机制提供了线索。
