The Rpf/DSF system and the regulation of virulence in the plant pathogen Xanthomonas campestris

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dc.check.date10000-01-01
dc.check.embargoformatBoth hard copy thesis and e-thesisen
dc.check.entireThesisEntire Thesis Restricted
dc.check.infoIndefiniteen
dc.check.opt-outYesen
dc.check.reasonThis thesis is due for publication or the author is actively seeking to publish this materialen
dc.contributor.advisorDow, Maxen
dc.contributor.authorO'Connell, Aileen Anne
dc.contributor.funderScience Foundation Irelanden
dc.date.accessioned2013-07-17T11:39:44Z
dc.date.issued2013
dc.date.submitted2013
dc.description.abstractThe full virulence of Xanthomonas campestris pv. campestris (Xcc) to plants depends upon cell-to-cell signalling mediated by the signal molecule DSF (for diffusible signal factor), that has been characterised as cis-11-methyl-2-dodecenoic acid. DSF-mediated signalling regulates motility, biofilm dynamics and the synthesis of particular virulence determinants. The synthesis and perception of the DSF signal molecule involves products of the rpf (regulation of pathogenicity factors) gene cluster. DSF synthesis is fully dependent on RpfF, which encodes a putative enoyl-CoA hydratase. A two-component system, comprising the complex sensor histidine kinase RpfC and the HD-GYP domain regulator RpfG, is implicated in DSF perception. The HD-GYP domain of RpfG is a phosphodiesterase working on cyclic di-GMP; DSF perception is thereby linked to the turnover of this intracellular second messenger. The full range of regulatory influences of the Rpf/DSF system and of cyclic di-GMP in Xcc has yet to be established. In order to further characterise the Rpf/DSF regulatory network in Xcc, a proteomic approach was used to compare protein expression in the wildtype and defined rpf mutants. This work shows that the Rpf/DSF system regulates a range of biological functions that are associated with virulence and biofilm formation but also reveals new functions mediated by DSF regulation. These functions include antibiotic resistance, detoxification and stress tolerance. Mutational analysis showed that several of these regulated protein functions contribute to virulence in Chinese radish. Interestingly, it was demonstrated that different patterns of protein expression are associated with mutations of rpfF, rpfC and rpfG. This suggests that RpfG and RpfC have broader roles in regulation other than perception and transduction of DSF. Taken together, this analysis indicates the broad and complex regulatory role of Rpf/DSF system and identifies a number of new functions under Rpf/DSF control, which were shown to play a role in virulence.en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationO'Connell, A. A. 2013. The Rpf/DSF system and the regulation of virulence in the plant pathogen Xanthomonas campestris. PhD Thesis, University College Cork.en
dc.identifier.endpage233
dc.identifier.urihttps://hdl.handle.net/10468/1188
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2013, Aileen A. O'Connellen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectCell-cell signallingen
dc.subjectMicrobiologyen
dc.subject.lcshXanthomonas campestrisen
dc.subject.lcshPlant-pathogen relationships--Molecular aspectsen
dc.subject.lcshPlant diseases--Molecular aspectsen
dc.thesis.opt-outtrue*
dc.titleThe Rpf/DSF system and the regulation of virulence in the plant pathogen Xanthomonas campestrisen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD (Science)en
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