title: Evolution of copper resistance in the kiwifruit pathogen Pseudomonas syringae pv. actinidiae through acquisition of integrative conjugative elements and plasmids.
abstract: Horizontal gene transfer can precipitate rapid evolutionary change. In 2010 the global pandemic of kiwifruit canker disease caused by Pseudomonas syringae pv. actinidiae (Psa) reached New Zealand. At the time of introduction, the single clone responsible for the outbreak was sensitive to copper, however, analysis of a sample of isolates taken in 2015 and 2016 showed that a quarter were copper resistant. Genome sequences of seven strains showed that copper resistance - comprising czc/cusABC and copABCD systems - along with resistance to arsenic and cadmium, was acquired via uptake of integrative conjugative elements (ICEs), but also plasmids. Comparative analysis showed ICEs to have a mosaic structure, with one being a tripartite arrangement of two different ICEs and a plasmid that were isolated in 1921 (USA), 1968 (NZ) and 1988 (Japan), from P. syringae pathogens of millet, wheat and kiwifruit respectively. Two of the Psa ICEs were nearly identical to two ICEs isolated from kiwifruit leaf colonists prior to the introduction of Psa into NZ. Additionally, we show ICE transfer in vitro and in planta, analyze fitness consequences of ICE carriage, capture the de novo formation of novel recombinant ICEs, and explore ICE host-range.
authors.affiliation: New Zealand Institute for Advanced Study, Massey University, Auckland, New Zealand.
authors.forename: Elena
authors.initials: E
authors.lastname: Colombi
authors.affiliation: New Zealand Institute for Advanced Study, Massey University, Auckland, New Zealand.
authors.forename: Christina
authors.initials: C
authors.lastname: Straub
authors.affiliation: Max Planck Institute for Evolutionary Biology, Plön, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Künzel
authors.affiliation: Plant and Food Research, Auckland, New Zealand.|School of Biological Sciences, University of Auckland, Auckland, New Zealand.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Templeton
authors.affiliation: New Zealand Institute for Advanced Study, Massey University, Auckland, New Zealand.|South China Botanical Institute, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Honour C
authors.initials: HC
authors.lastname: McCann
authors.affiliation: New Zealand Institute for Advanced Study, Massey University, Auckland, New Zealand.|Max Planck Institute for Evolutionary Biology, Plön, Germany.|Ecole Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris-Tech), PSL Research University, Paris, France.
authors.forename: Paul B
authors.initials: PB
authors.lastname: Rainey
mesh_terms: D029042:Actinidia / Q000382:microbiology*; D005075:Biological Evolution; D003227:Conjugation, Genetic; D003300:Copper / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005638:Fruit / Q000382:microbiology; D058507:Host Specificity; D010935:Plant Diseases / Q000382:microbiology*; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D044224:Pseudomonas syringae / Q000187:drug effects* / Q000235:genetics* / Q000502:physiology
chemical_list: D003300:Copper