title: Cyclic di-GMP signalling in the virulence and environmental adaptation of Xanthomonas campestris.
abstract: Cyclic di-GMP is a second messenger with a role in regulation of a range of cellular functions in diverse bacteria including the virulence of pathogens. Cellular levels of cyclic di-GMP are controlled through synthesis, catalysed by the GGDEF protein domain, and degradation by EAL or HD-GYP domains. Here we report a comprehensive study of cyclic di-GMP signalling in bacterial disease in which we examine the contribution of all proteins with GGDEF, EAL or HD-GYP domains to virulence and virulence factor production in the phytopathogen Xanthomonas campestris pathovar campestris (Xcc). Genes with significant roles in virulence to plants included those encoding proteins whose probable function is in cyclic-di-GMP synthesis as well as others (including the HD-GYP domain regulator RpfG) implicated in cyclic di-GMP degradation. Furthermore, RpfG controlled expression of a subset of these genes. A partially overlapping set of elements controlled the production of virulence factors in vitro. Other GGDEF-EAL domain proteins had no effect on virulence factor synthesis but did influence motility. These findings indicate the existence of a regulatory network that may allow Xcc to integrate information from diverse environmental inputs to modulate virulence factor synthesis as well as of cyclic di-GMP signalling systems dedicated to other specific tasks.
authors.affiliation: BIOMERIT Research Centre, Department of Microbiology, BioSciences Institute, National University of Ireland, Cork, Ireland.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Ryan
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Fouhy
authors.forename: Jean F
authors.initials: JF
authors.lastname: Lucey
authors.forename: Bo-Le
authors.initials: BL
authors.lastname: Jiang
authors.forename: Yong-Qiang
authors.initials: YQ
authors.lastname: He
authors.forename: Jia-Xun
authors.initials: JX
authors.lastname: Feng
authors.forename: Ji-Liang
authors.initials: JL
authors.lastname: Tang
authors.forename: J Maxwell
authors.initials: JM
authors.lastname: Dow
mesh_terms: D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000096:biosynthesis; D018441:Biofilms / Q000254:growth & development; D004251:DNA Transposable Elements / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D006150:Guanine Nucleotides / Q000378:metabolism*; D009068:Movement; D016254:Mutagenesis, Insertional; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D031224:Raphanus / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014158:Transcription, Genetic; D014774:Virulence; D037521:Virulence Factors / Q000096:biosynthesis; D016959:Xanthomonas campestris / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D006150:Guanine Nucleotides; D012329:RNA, Bacterial; D012333:RNA, Messenger; D037521:Virulence Factors; C078170:2',3'-cyclic GMP