Regulation of resistance to copper in Xanthomonas axonopodis pv. vesicatoria.

Appl Environ Microbiol

Department of Plant Pathology, University of California, Riverside, CA 92521, USA.

Published: February 2005

Copper-resistant strains of Xanthomonas axonopodis pv. vesicatoria were previously shown to carry plasmid-borne copper resistance genes related to the cop and pco operons of Pseudomonas syringae and Escherichia coli, respectively. However, instead of the two-component (copRS and pcoRS) systems determining copper-inducible expression of the operons in P. syringae and E. coli, a novel open reading frame, copL, was found to be required for copper-inducible expression of the downstream multicopper oxidase copA in X. axonopodis. copL encodes a predicted protein product of 122 amino acids that is rich in histidine and cysteine residues, suggesting a possible direct interaction with copper. Deletions or frameshift mutations within copL, as well as an amino acid substitution generated at the putative start codon of copL, caused a loss of copper-inducible transcriptional activation of copA. A nonpolar insertion of a kanamycin resistance gene in copL resulted in copper sensitivity in the wild-type strain. However, repeated attempts to complement copL mutations in trans failed. Analysis of the genomic sequence databases shows that there are copL homologs upstream of copAB genes in X. axonopodis pv. citri, X. campestris pv. campestris, and Xylella fastidiosa. The cloned promoter area upstream of copA in X. axonopodis pv. vesicatoria did not function in Pseudomonas syringae or in E. coli, nor did the P. syringae cop promoter function in Xanthomonas. However, a transcriptional fusion of the Xanthomonas cop promoter with the Pseudomonas copABCDRS was able to confer resistance to copper in Xanthomonas, showing divergence in the mechanisms of regulation of the resistance to copper in phytopathogenic bacteria.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC546827PMC
http://dx.doi.org/10.1128/AEM.71.2.782-789.2005DOI Listing

Publication Analysis

Top Keywords

resistance copper
12
axonopodis vesicatoria
12
regulation resistance
8
copper xanthomonas
8
xanthomonas axonopodis
8
pseudomonas syringae
8
copper-inducible expression
8
syringae coli
8
copa axonopodis
8
cop promoter
8

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!