Plasmid biology of rhizobium leguminosarum: novel conjugation system and glycerol catabolic genes

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dc.contributor.advisorHynes, Michael F.
dc.contributor.authorDing, Hao
dc.date.accessioned2017-12-18T22:33:55Z
dc.date.available2017-12-18T22:33:55Z
dc.date.issued2012
dc.descriptionBibliography: p. 211-230en
dc.descriptionMany pages are in colour.en
dc.description.abstractLarge plasmids in rhizobia play important roles in rhizobia-legume symbioses and bacterial survival and competitiveness in the rhizosphere. In R. leguminosarum bv. viciae VF39SM, a novel conjugation system on plasmid pRleVF39b was isolated and found to be different from the rhizobial quorum sensing-regulated or the RctA-repressed conjugation systems. The entire transfer region on pRleVF39b encompasses a trb-like operon and traG, encoding the mating pore formation component and the coupling protein, and a relaxase gene traA located 9 kb downstream of the trb operon. Mutations in any of the above genes completely abolished the transfer of pRleVF39b. The transfer of pRleVF39b was affected mainly by its host genetic background. Under the conditions tested, pRle VF3 9b transferred at highest frequency at about 10-4 transconjugants per recipient from plasmid-free Agrobacterium tumefaciens UBAPF2 to another Agrobacterium recipient. The transfer frequency decreased about 10 to 100-fold when Rhizobium was the donor, and decreased at least 1000-fold when Rhizobium was the recipient. An xre-type transcriptional repressor gene trbR was identified in the region between traG and traA. Mutation in trbR led to SO-fold increases in trb operon expression and pRleVF39b transfer. A glycerol uptake and catabolic locus on pRleVF39c was found to comprise a glpR gene, encoding a transcriptional regulator, and the glp operon, including a glpD gene, encoding glycerol 3-phosphate dehydrogenase, glpSTPQUV encoding an ATP binding cassette transporter, and a glpK gene encoding glycerol kinase. All the genes within the operon were required for growth on glycerol, except for glpK whose function can be partially complemented by a glpKch gene on the chromosome. The glp operon was inducible by glycerol, glycerol 3-phosphate, and pea seed exudates. GlpR represses the expression of the glp operon in the absence of inducer. Glycerol uptake in Rhizobium was shown to be an active process mediated by an ABC transporter. Mutants that are unable to utilize glycerol as a sole carbon source were less competitive in nodulating peas than the wild-type, indicating that glycerol catabolism might confer advantages to the bacterium in the rhizosphere or in plants.
dc.format.extentxvii, 238 leaves : ill. ; 30 cm.en
dc.identifier.citationDing, H. (2012). Plasmid biology of rhizobium leguminosarum: novel conjugation system and glycerol catabolic genes (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/4875en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/4875
dc.identifier.urihttp://hdl.handle.net/1880/105876
dc.language.isoeng
dc.publisher.institutionUniversity of Calgaryen
dc.publisher.placeCalgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.titlePlasmid biology of rhizobium leguminosarum: novel conjugation system and glycerol catabolic genes
dc.typedoctoral thesis
thesis.degree.disciplineBiological Sciences
thesis.degree.grantorUniversity of Calgary
thesis.degree.nameDoctor of Philosophy (PhD)
ucalgary.item.requestcopytrue
ucalgary.thesis.accessionTheses Collection 58.002:Box 2106 627942976
ucalgary.thesis.notesUARCen
ucalgary.thesis.uarcreleaseyen
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