title: An H-NS-like protein involved in the negative regulation of hrp genes in Xanthomonas oryzae pv. oryzae.
abstract: hrp genes encode components of a type III secretion (T3S) system and play crucial roles in the pathogenicity of the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo). A histone-like nucleoid-structuring (H-NS) protein binds DNA and acts as a global transcriptional repressor. Here, we investigated the involvement of an h-ns-like gene, named xrvB, in the expression of hrp genes in Xoo. Under the hrp-inducing culture condition, the expression of a key hrp regulator HrpG increased in the XrvB mutant, followed by activation of the downstream gene expression. Also, in planta, the secretion of a T3S protein (XopR) was activated by the mutation in xrvB. Gel retardation assay indicated that XrvB has DNA-binding activity, but without a preference for the promoter region of hrpG. The results suggest that XrvB negatively regulates hrp gene expression and that an unknown factor(s) mediates the regulation of hrpG expression by XrvB.
authors.affiliation: Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto Prefectural University, Kyoto, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kametani-Ikawa
authors.forename: Seiji
authors.initials: S
authors.lastname: Tsuge
authors.forename: Ayako
authors.initials: A
authors.lastname: Furutani
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Ochiai
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial; D010935:Plant Diseases / Q000382:microbiology; D014026:Nicotiana / Q000382:microbiology; D014974:Xanthomonas / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria