title: virA and virG are the Ti-plasmid functions required for chemotaxis of Agrobacterium tumefaciens towards acetosyringone.
abstract: Octopine and nopaline Ti-plasmids confer upon Agrobacterium tumefaciens C58C1 the ability to respond chemotactically to the vir-inducing phenolic wound exudate, acetosyringone. A. tumefaciens C58C1 containing Ti-plasmids with Tn5 insertions in virB, C, D or E exhibited marked chemotaxis towards acetosyringone. However, Ti-plasmids with mutations in virA or virG were unable to confer the responsive phenotype. Of the cosmid clones pVK219 (virAB) pVK221 (virBGC) pVK225 (virGCDE) and pVK257 (virABGC) mobilized to cured A. tumefaciens C58C1, only pVK257 bestowed acetosyringone chemotaxis. virA and virG are thus required for chemotaxis of A. tumefaciens towards acetosyringone. This suggests a multifunctional role for virA and virG: at low concentrations of acetosyringone they mediate chemotaxis and at higher concentrations they effect vir-induction.
authors.affiliation: Department of Botany, University of Durham, UK.
authors.forename: C H
authors.initials: CH
authors.lastname: Shaw
authors.forename: A M
authors.initials: AM
authors.lastname: Ashby
authors.forename: A
authors.initials: A
authors.lastname: Brown
authors.forename: C
authors.initials: C
authors.lastname: Royal
authors.forename: G J
authors.initials: GJ
authors.lastname: Loake
authors.forename: C H
authors.initials: CH
authors.lastname: Shaw
mesh_terms: D000098:Acetophenones / Q000502:physiology*; D001120:Arginine / Q000031:analogs & derivatives / Q000235:genetics; D001426:Bacterial Proteins; D002630:Chemotactic Factors / Q000502:physiology; D002633:Chemotaxis; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003360:Cosmids; D005786:Gene Expression Regulation; D008565:Membrane Proteins / Q000502:physiology; D000072236:Methyl-Accepting Chemotaxis Proteins; D009154:Mutation; D010957:Plasmids; D012231:Rhizobium / Q000235:genetics*; D014162:Transfection
chemical_list: D000098:Acetophenones; D001426:Bacterial Proteins; D002630:Chemotactic Factors; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C008666:nopaline; C005394:octopine; C051667:acetosyringone; D001120:Arginine