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Population structure of the invasive forest pathogen H ymenoscyphus pseudoalbidus
Author(s) -
Gross Andrin,
Hosoya Tsuyoshi,
Queloz Valentin
Publication year - 2014
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12792
Subject(s) - biology , genetic diversity , biological dispersal , genetic structure , isolation by distance , population , population bottleneck , population genetics , evolutionary biology , microsatellite , genetic variation , ecology , phylogenetic tree , allele , genetics , gene , demography , sociology
Understanding the genetic diversity and structure of invasive pathogens in source and in introduced areas is crucial to the revelation of hidden biological features of an organism, to the reconstruction of the course of invasions and to the establishment of effective control measures. H ymenoscyphus pseudoalbidus (anamorph: C halara fraxinea ) is an invasive and highly destructive fungal pathogen found on common ash Fraxinus excelsior in Europe and is native to E ast A sia. To gain insights into its dispersal mechanisms and history of invasion, we used microsatellite markers and characterized the genetic structure and diversity of H . pseudoalbidus populations at three spatial levels: (i) between E urope and Japan, (ii) in E urope and (iii) at the epidemic's front in S witzerland. Phylogenetic and network analysis demonstrated that individuals from both regions are conspecific. However, populations from Japan harboured a higher genetic diversity and were genetically differentiated from European ones. No evident population structure was found among the 1208 European strains using Bayesian and multivariate clustering analysis. Only the distribution of genetic diversity in space, pairwise population differentiation ( G ST ) and the spatial analysis of principal components revealed a faint geographical pattern around Europe. A significant allele deficiency in most European populations pointed to a recent genetic bottleneck, whereas no pattern of isolation by distance was found. Our data suggest that H . pseudoalbidus was introduced just once by at least two individuals. The potential source region of H . pseudoalbidus is vast, and further investigations are required for a more accurate localization of the source population.