New insights into virulence mechanisms of rice pathogen Acidovorax avenae subsp. avenae strain RS-1 following exposure to ß-lactam antibiotics.
New insights into virulence mechanisms of rice pathogen Acidovorax avenae subsp. avenae strain RS-1 following exposure to ß-lactam antibiotics.
复制标题
接触β-内酰胺抗生素后水稻病原体燕麦酸食菌亚种燕麦菌株RS-1毒力机制的新见解
DOI：
10.1038/srep22241
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发表时间：
2016-02-26
影响因子：
4.6
通讯作者：
Chen G
中科院分区：
文献类型：
--
作者：
Li B;Ge M;Zhang Y;Wang L;Ibrahim M;Wang Y;Sun G;Chen G
最近的研究表明，病原体的毒力可以通过暴露于抗生素而改变，即使生长速度不受影响。研究这种现象为理解细菌病原体的毒力机制提供了新的见解。本研究探讨了水稻病原菌燕麦食酸菌亚种的表型和转录组反应。燕麦（Aaa）RS-1菌株对β-内酰胺类抗生素尤其是氨苄青霉素（Ampicillin，氨苄青霉素）的敏感性。我们的研究结果表明，暴露于大肠杆菌不影响细菌的生长和生物膜的形成，但改变的毒力，定植能力，胞外聚合物的组成和VI型分泌系统（T6 SS）效应HCP的分泌。基于全基因组转录组学分析，这种毒力减弱与已知毒力相关基因的独特或差异表达有关。用21个选定的T6 SS基因的定量实时PCR验证了通过RNA-Seq产生的表达数据的可靠性，其中在暴露于α-葡聚糖下观察到hcp基因表达的显著下调，对应于Hcp分泌的减少。HCP被强调为潜在的靶点，在暴露于HBV和HCP基因突变之间的毒力相关表型中观察到类似的变化。此外，在4个差异表达的T6 SS基因的敲除突变体中，HCP分泌减少。
Recent research has shown that pathogen virulence can be altered by exposure to antibiotics, even when the growth rate is unaffected. Investigating this phenomenon provides new insights into understanding the virulence mechanisms of bacterial pathogens. This study investigates the phenotypic and transcriptomic responses of the rice pathogenic bacterium Acidovorax avenae subsp. avenae (Aaa) strain RS-1 to ß-lactam antibiotics especially Ampicillin (Amp). Our results indicate that exposure to Amp does not influence bacterial growth and biofilm formation, but alters the virulence, colonization capacity, composition of extracellular polymeric substances and secretion of Type VI secretion system (T6SS) effector Hcp. This attenuation in virulence is linked to unique or differential expression of known virulence-associated genes based on genome-wide transcriptomic analysis. The reliability of expression data generated by RNA-Seq was verified with quantitative real-time PCR of 21 selected T6SS genes, where significant down-regulation in expression of hcp gene, corresponding to the reduction in secretion of Hcp, was observed under exposure to Amp. Hcp is highlighted as a potential target for Amp, with similar changes observed in virulence-associated phenotypes between exposure to Amp and mutation of hcp gene. In addition, Hcp secretion is reduced in knockout mutants of 4 differentially expressed T6SS genes.