The copper resistance operon copAB from Xanthomonas axonopodis pathovar citri: gene inactivation results in copper sensitivity
- 1 February 2008
- journal article
- Published by Microbiology Society in Microbiology
- Vol. 154 (2), 402-412
- https://doi.org/10.1099/mic.0.2007/013821-0
Abstract
Xanthomonas axonopodis pv. citri (Xac) causes citrus canker and the completion of the Xac genome sequence has opened up the possibility of investigating basic cellular mechanisms at the genomic level. Copper compounds have been extensively used in agriculture to control plant diseases. The copA and copB genes, identified by annotation of the Xac genome, encode homologues of proteins involved in copper resistance. A gene expression assay by Northern blotting revealed that copA and copB are expressed as a unique transcript specifically induced by copper. Synthesis of the gene products was also induced by copper, reaching a maximum level at 4 h after addition of copper to the culture medium. CopA was a cytosolic protein and CopB was detected in the cytoplasmic membrane. The gene encoding CopA was disrupted by the insertion of a transposon, leading to mutant strains that were unable to grow in culture medium containing copper, even at the lowest CuSO4 concentration tested (0.25 mM), whereas the wild-type strain was able to grow in the presence of 1 mM copper. Cell suspensions of the wild-type and mutant strains in different copper concentrations were inoculated in lemon leaves to analyse their ability to induce citrus canker symptoms. Cells of mutant strains showed higher sensitivity than the wild-type strain in the presence of copper, i.e. they were not able to induce citrus canker symptoms at high copper concentrations and exhibited a more retarded growth in planta.Keywords
This publication has 26 references indexed in Scilit:
- Structure and Mechanism of a Metal-Sensing Regulatory RNACell, 2007
- The Tat Pathway of the Plant Pathogen Pseudomonas syringae is Required for Optimal VirulenceMolecular Plant-Microbe Interactions®, 2006
- Identification of a Twin-Arginine Translocation System in Pseudomonas syringae pv. tomato DC3000 and Its Contribution to Pathogenicity and FitnessJournal of Bacteriology, 2005
- Characterization of a Unique Chromosomal Copper Resistance Gene Cluster from X anthomonas campestris pv. vesicatoriaApplied and Environmental Microbiology, 2005
- Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000Proceedings of the National Academy of Sciences of the United States of America, 2005
- Molecular Analysis of the Copper-Transporting Efflux System CusCFBA of Escherichia coliJournal of Bacteriology, 2003
- The Tat protein translocation pathway and its role in microbial physiologyPublished by Elsevier BV ,2003
- Comparison of the genomes of two Xanthomonas pathogens with differing host specificitiesNature, 2002
- Molecular genetics and transport analysis of the copper‐resistance determinant (pco) from Escherichia coli plasmid pRJ1004Molecular Microbiology, 1995
- Copper resistance in Pseudomonas syringae mediated by periplasmic and outer membrane proteins.Proceedings of the National Academy of Sciences of the United States of America, 1991