Conjugation in Pseudomonas syringae pv. Actinidiae (Psa)

Abstract

Copper-resistant field isolates of the kiwifruit pathogen Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) have been identified in New Zealand. These isolates invariably carry large novel genetic elements, such as plasmids or integrative conjugative elements (ICEs), acquired by horizontal transfer from non-Psa3 species of bacteria already present in New Zealand. Here, we have determined whether these acquired elements are both necessary and sufficient to produce the observed copper-resistant phenotype. Methods were developed to transfer the ~100,000-bp ICEs and large (>100,000 bp) plasmids from the copper-resistant isolates to a sensitive recipient strain using natural conjugation. The IC..