virA和virG是根癌土壤杆菌向乙酰丁香酮趋化所必需的Ti质粒功能。

virA and virG are the Ti-plasmid functions required for chemotaxis of Agrobacterium tumefaciens towards acetosyringone.

作者信息

Shaw C H, Ashby A M, Brown A, Royal C, Loake G J, Shaw C H

机构信息

Department of Botany, University of Durham, UK.

出版信息

Mol Microbiol. 1988 May;2(3):413-7. doi: 10.1111/j.1365-2958.1988.tb00046.x.

DOI:10.1111/j.1365-2958.1988.tb00046.x

PMID:3398775

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.

摘要

章鱼碱型和胭脂碱型Ti质粒赋予根癌土壤杆菌C58C1对诱导Vir区的酚类伤口渗出物乙酰丁香酮产生趋化反应的能力。含有在virB、C、D或E中插入Tn5的Ti质粒的根癌土壤杆菌C58C1对乙酰丁香酮表现出明显的趋化性。然而，在virA或virG中发生突变的Ti质粒无法赋予这种反应表型。在转移到无Ti质粒的根癌土壤杆菌C58C1中的黏粒克隆pVK219（virAB）、pVK221（virBGC）、pVK225（virGCDE）和pVK257（virABGC）中，只有pVK257赋予了对乙酰丁香酮的趋化性。因此，根癌土壤杆菌对乙酰丁香酮的趋化性需要virA和virG。这表明virA和virG具有多功能作用：在低浓度乙酰丁香酮时，它们介导趋化作用；在高浓度时，它们影响Vir区诱导。