Cellular Localization and Functional Analysis of the Protein Encoded by the Chromosomal VirulenceGene(acvB) ofAgrobacterium tumefaciens

Abstract

A chromosomal virulence gene, acvB, of Agrobacterium tumefaciens [J. Bacteriol., 175, 3208-3212 (1993)] was over-expressed in Escherichia coli. A 47-kDa protein was produced and localized in the periplasmic space of E. coli. Amino acid sequence analysis of its N-terminal demonstrated that a signal peptide of 24 amino acids was cleaved from the pre AcvB protein to produce the mature 47-kDa protein. Western-blot analysis using the antiserum against the AcvB protein detected a 47-kDa protein in the periplasmic space only with strain A208 (acvB+). The amount of AcvB protein synthesized was not increased in strain A208 by induction with acetosyringone (100 microM). There was observed no significant difference in induction by acetosyringone of virB::lacZ, virD::lacZ, and virE::lacZ fusion genes regardless of the presence or absence of the acvB gene. The T-strand (lower strand of T-DNA) was detected in strains A208 as well as B119 (acvB-) which were cultured in induction medium containing acetosyringone. AcvB protein bound to single-stranded DNAs with no apparent sequence specificity. The results suggest that AcvB protein binds to the T-strand in periplasm and mediates the transfer of the T-strand from A. tumefaciens to the host plant cell.

Agrobacterium tumefaciens ExoR Controls Acid Response Genes and Impacts Exopolysaccharide Synthesis, Horizontal Gene Transfer, and Virulence Gene Expression

“…Besides virG, virH1, and virH2 (log 2 FC, 3.3, 1.1, and 0.9, respectively), other genes related to virulence were upregulated in the ⌬exoR mutant, including the agrobacterium chromosomal virulence gene acvB (log 2 FC, 0.8) and the trans-zeatin synthase gene tzs (log 2 FC, 0.63) (49,50). The chvI-chvG locus, which responds to low pH and is required for virulence (20), was also upregulated, though we included these genes in the "transcription factor, GGDEF/EAL, and two-component system" group, not the "virulence" group.…”

Burkholderia cenocepacia Requires a Periplasmic HtrA Protease for Growth under Thermal and Osmotic Stress and for Survival In Vivo

“…Periplasmic proteins were isolated as described previously, with the following modifications (23). Bacterial cells were pelleted by centrifugation (9,000 ϫ g for 10 min) and resuspended in 2.5 ml of lysis buffer (20% [wt/vol] sucrose, 30 mM Tris-HCl [pH 8.0], 1 mM EDTA [pH 8.0], 3.5 mg/ml lysozyme).…”

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

“…Both R. tropici atvA and A. tumefaciens acvB mutants are acid sensitive, indicating that the two genes are required for acid tolerance (506). The functions of these genes are unknown, although the AcvB protein (or its Tiplasmid-encoded homolog, VirJ) is required for tumorigenesis (255,260,369,533).…”