Genetic structure of an expanding Armillaria root rot fungus (Armillaria ostoyae) population in a managed pine forest in southwestern France
Langue
en
Article de revue
Ce document a été publié dans
Molecular Ecology. 2008, vol. 17, n° 14, p. 3366-3378
Wiley
Résumé en anglais
The Landes de Gascogne forest (southwestern France) is the largest maritime pine (Pinus pinaster) plantation in Europe. Armillaria root disease (Armillaria ostoyae) has been reported since the early 1920s in the coastal ...Lire la suite >
The Landes de Gascogne forest (southwestern France) is the largest maritime pine (Pinus pinaster) plantation in Europe. Armillaria root disease (Armillaria ostoyae) has been reported since the early 1920s in the coastal area (western sector), but its incidence over the last 20 years has increased in the eastern sector. We investigated the genetic structure of the A. ostoyae population in this forest, focusing particularly on geographical differentiation potentially indicative of disease expansion in this area. In total, 531 isolates obtained from mycelial fans on symptomatic trees or undecayed stumps in 31 different disease foci were genotyped at five microsatellite loci. In 20 of these disease foci, a single genotype dominated, reflecting a predominantly clonal local spread of A. ostoyae. By contrast, at the regional scale, A. ostoyae probably spreads mostly via basidiospores (sexual spores), as no genotype common to several disease foci was identified. The absence of a clear pattern of isolation by distance may indicate either substantial gene flow or stochastic colonisation independent of spatial distance. The gradient of genetic diversity from the coast inwards and the greater genetic divergence of the eastern disease foci are consistent with the expansion of the A. ostoyae population from the coast eastwards.< Réduire
Mots clés
ARMILLARIA
MICROSATELLITES
POPULATION EXPANSION
Mots clés en anglais
BASIDIOSPORES
DISPERSAL
GENETIC DIFFERENTIATION
NATIVE PATHOGEN
PIN MARITIME
Origine
Importé de halUnités de recherche