title: epv, Encoding a hypothetical protein, is regulated by DSF-mediating quorum sensing as well as global regulator Clp and is required for optimal virulence in Xanthomonas oryzae pv. oryzicola.
abstract: Xanthomonas oryzae pv. oryzicola causes bacterial leaf streak in rice, a destructive disease worldwide. In this study, six putative hypothetical secreted proteins, which were absent in X. oryzae pv. oryzae, were detected from X. oryzae pv. oryzicola strain BLS256. Disruption-based mutagenesis study revealed that one of them, Xoc_15235, named as extracellular polysaccharide and virulence-related gene (epv), was required for the optimal virulence in host rice but not for the induction of a hypersensitive reaction in nonhost tobacco. Sequence analysis revealed that epv was highly conserved in Xanthomonas spp. (except X. oryzae pv. oryzae). In-frame deletion of epv in X. oryzae pv. oryzicola dramatically impaired pathogen virulence and extracellular polysaccharide (EPS) production, one of the important known virulence-associated functions in Xanthomonas spp. Quantitative real-time reverse-transcription polymerase chain reaction showed that expression of both gumB (a gene encoding exopolysaccharide xanthan biosynthesis export protein) and a known virulence-related gene, pgk (encoding phosphoglycerate kinase), were obviously reduced in the epv-deletion mutant compared with the wild-type strain Rs105. In addition, we observed that epv was positively regulated by both diffusible signal factor and global regulator Clp in X. oryzae pv. oryzicola. Taken together, the novel roles and genetics of epv of X. oryzae pv. oryzicola in the EPS production and virulence were investigated for the first time.
authors.affiliation: College of Plant Protection and Key Laboratory of Integrated Management of Corp Diseases and Pests, Ministry of Education, Nanjing Agricultural University, China.
authors.forename: Guoliang
authors.initials: G
authors.lastname: Qian
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yijin
authors.initials: Y
authors.lastname: Zhou
authors.forename: Chunhui
authors.initials: C
authors.lastname: Liu
authors.forename: Yancun
authors.initials: Y
authors.lastname: Zhao
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Song
authors.forename: Jiaqin
authors.initials: J
authors.lastname: Fan
authors.forename: Baishi
authors.initials: B
authors.lastname: Hu
authors.forename: Fengquan
authors.initials: F
authors.lastname: Liu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D009154:Mutation; D012275:Oryza / Q000382:microbiology; D010935:Plant Diseases / Q000382:microbiology; D053038:Quorum Sensing / Q000502:physiology*; D014026:Nicotiana; D014158:Transcription, Genetic; D014774:Virulence; D014974:Xanthomonas / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*
chemical_list: D001426:Bacterial Proteins