Genetic basis of copper resistance in New Zealand strains of Pseudomonas syringae

Abstract

Strains of Pseudomonas syringae able to grow on minimal medium containing 500 mg/litre of copper sulphate were selected from a collection of streptomycinresistant strains isolated in New Zealand From one of these copperresistant strains a 13 kb fragment of DNA was isolated by PCR using primers designed on genes reported to be associated with copper resistance Sequencing of this fragment revealed that a 572 bp and a 275 bp portion had 98 and 95 similarity with ORF A of P syringae pv actinidiae a gene that codes for copper resistance Smaller portions of this 13 kb fragment were highly similar (89 to 100) to portions of another gene involved in copper resistance (copA) from Pseudomonas syringae pv tomato Using this 13 kb fragment as a probe homologous DNA was detected in eight other strains of P syringae which were all subsequently found to be resistant to copper