title: New insights into virulence mechanisms of rice pathogen Acidovorax avenae subsp. avenae strain RS-1 following exposure to ß-lactam antibiotics.
abstract: 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.
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China.
authors.forename: Mengyu
authors.initials: M
authors.lastname: Ge
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China.|Department of Biosciences, COMSATS Institute of Information technology Sahiwal Campus, Sahiwal, Pakistan.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ibrahim
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Plant Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory Breeding Base for Zhejiang Sustainable Plant Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors.forename: Guochang
authors.initials: G
authors.lastname: Sun
authors.affiliation: School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China.
authors.forename: Gongyou
authors.initials: G
authors.lastname: Chen
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D016000:Cluster Analysis; D042621:Comamonadaceae / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity; D020869:Gene Expression Profiling / Q000379:methods; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D054884:Host-Pathogen Interactions / Q000187:drug effects; D012275:Oryza / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014774:Virulence / Q000187:drug effects / Q000235:genetics; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D047090:beta-Lactams; D000667:Ampicillin