title: Genetic diversification of the chestnut blight fungus Cryphonectria parasitica and its associated hypovirus in Germany.
abstract: Chestnut blight in south-western Germany was first reported in 1992 and is since expanding in distribution. Here we investigated the invasion history of Cryphonectria parasitica and its associated hypovirus. For this, we characterized 284 isolates collected between 1992 and 2012 for hypovirulence, vegetative compatibility (vc), mating type, and microsatellite haplotype. A total of 27 haplotypes and 15 vc types were observed, although the C. parasitica population analyzed is currently dominated to 50 % by one haplotype and to 64 % by the vc type EU-2. Structure analysis indicated two divergent genetic pools. Over 66 % of the haplotypes belonged to a pool probably originating from northern Italy. Further diversification is expected due to ongoing sexual recombination, but also to new migration and additional introductions. Cryphonectria hypovirus 1 (CHV-1) was found in four of five C. parasitica populations from Baden-Württemberg. Genetic analysis of the 35 CHV-1 isolates obtained revealed that they all belong to the German subtype, although they have clearly diverged from the first German hypovirus isolated in 1992. Our study suggests that C. parasitica has been introduced into Germany several times from two different gene pools, whereas the hypovirus most probably has a single origin.
authors: FVA Forest Research Institute of Baden-Württemberg (FVA-BW), Dept. Forest Protection, Wonnhaldestr. 4, D-79100 Freiburg, Germany. Electronic address: franziska.peters@forst.bwl.de.
authors: Franziska S
authors: FS
authors: Peters
authors: FVA Forest Research Institute of Baden-Württemberg (FVA-BW), Dept. Forest Protection, Wonnhaldestr. 4, D-79100 Freiburg, Germany. Electronic address: johanna.busskamp@forst.bwl.de.
authors: Johanna
authors: J
authors: Busskamp
authors: WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland. Electronic address: simone.prospero@wsl.ch.
authors: Simone
authors: S
authors: Prospero
authors: WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903 Birmensdorf, Switzerland. Electronic address: daniel.rigling@wsl.ch.
authors: Daniel
authors: D
authors: Rigling
authors: FVA Forest Research Institute of Baden-Württemberg (FVA-BW), Dept. Forest Protection, Wonnhaldestr. 4, D-79100 Freiburg, Germany. Electronic address: berthold.metzler@forst.bwl.de.
authors: Berthold
authors: B
authors: Metzler
mesh_terms: D001203:Ascomycota / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000821:virology*; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D029962:Fagaceae / Q000382:microbiology; D049770:Genes, Mating Type, Fungal; D014644:Genetic Variation; D005858:Germany; D006239:Haplotypes; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D012367:RNA, Viral / Q000235:genetics; D017422:Sequence Analysis, DNA; D014780:Viruses / Q000145:classification* / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D012367:RNA, Viral
keywords: Cryphonectria hypovirus 1; Genetic diversity; Introduction; Invasive species; Sexual reproduction