Open AccessCopper Resistance in Pseudomonas syringae Strains Isolated from Mango Is Encoded Mainly by Plasmids
Author(s) -
Francisco M. Cazorla,
Eva Arrebola,
Ane Sesma,
Alejandro Pérez-Garcı́a,
Juan Codina,
Jesús Murillo,
Antonio de Vicente
Publication year - 2002
Publication title -
phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.264
H-Index - 131
eISSN - 1943-7684
pISSN - 0031-949X
DOI - 10.1094/phyto.2002.92.8.909
Subject(s) - pseudomonas syringae , biology , plasmid , microbiology and biotechnology , copper , bacteria , pseudomonadaceae , southern blot , pseudomonas , gene , genetics , chemistry , organic chemistry
Bacterial apical necrosis of mango, elicited by Pseudomonas syringae pv. syringae, limits fruit production in southern Spain and Portugal. Examination of a collection of P. syringae pv. syringae isolates for copper resistance showed that 59% were resistant to cupric sulfate. The survey of a mango orchard revealed an increase in frequencies of copper-resistant bacteria after repeated treatments with Bordeaux mixture. These data suggest that selection of copper-resistant strains could be a major reason for control failures following management with copper bactericides. Most copper-resistant isolates harbored plasmids, although the majority of them contained a 62-kb plasmid that also was present in copper-sensitive strains. The 62-kb plasmids were differentiated by restriction enzyme analysis and hybridization to copABCD DNA. The most frequently found copper-resistant plasmid type (62.1) was transferable by conjugation. Southern blot hybridizations showed that genetic determinants partially homologous to copABCD were present in all the copper-resistant strains examined, and usually were associated with plasmids; these determinants were not detected in copper-sensitive strains. The selective pressure exerted by copper bactericide sprays on the diversity of copper resistance determinants in bacterial populations of mango is discussed.