title: Adaptation to enemy shifts: rapid resistance evolution to local Vibrio spp. in invasive Pacific oysters.
abstract: One hypothesis for the success of invasive species is reduced pathogen burden, resulting from a release from infections or high immunological fitness of invaders. Despite strong selection exerted on the host, the evolutionary response of invaders to newly acquired pathogens has rarely been considered. The two independent and genetically distinct invasions of the Pacific oyster Crassostrea gigas into the North Sea represent an ideal model system to study fast evolutionary responses of invasive populations. By exposing both invasion sources to ubiquitous and phylogenetically diverse pathogens (Vibrio spp.), we demonstrate that within a few generations hosts adapted to newly encountered pathogen communities. However, local adaptation only became apparent in selective environments, i.e. at elevated temperatures reflecting patterns of disease outbreaks in natural populations. Resistance against sympatric and allopatric Vibrio spp. strains was dominantly inherited in crosses between both invasion sources, resulting in an overall higher resistance of admixed individuals than pure lines. Therefore, we suggest that a simple genetic resistance mechanism of the host is matched to a common virulence mechanism shared by local Vibrio strains. This combination might have facilitated a fast evolutionary response that can explain another dimension of why invasive species can be so successful in newly invaded ranges.
authors.affiliation: Coastal Ecology, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Wadden Sea Station Sylt, Hafenstraße 43, List 25992, Germany cwendling@geomar.de.
authors.forename: Carolin C
authors.initials: CC
authors.lastname: Wendling
authors.affiliation: Coastal Ecology, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Wadden Sea Station Sylt, Hafenstraße 43, List 25992, Germany.
authors.forename: K Mathias
authors.initials: KM
authors.lastname: Wegner
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D005075:Biological Evolution; D049896:Crassostrea / Q000235:genetics* / Q000382:microbiology*; D014644:Genetic Variation; D054884:Host-Pathogen Interactions; D058865:Introduced Species; D008969:Molecular Sequence Data; D009659:North Sea; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014733:Vibrio / Q000235:genetics / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins
keywords: dominant inheritance; host-parasite coevolution; local adaptation; multi-host parasites; multi-locus sequence typing