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Conference paper, 2012

A genome-wide association study identifies genomic regions for virulence in Heterobasidion annosum s.s

Dalman, Kerstin; Himmelstrand, Kajsa; Olson, Åke; Lind, Mårten; Brandström Durling, Mikael; Stenlid, Jan


Heterobasidion annosum (Fr.) Bref. sensu lato (s.l.) is a necrotrophic pathogen that causessevere damage to coniferous forests in the Northern Hemisphere. A genome-wide association studyanalysing the virulence of H. annosum sensu stricto (s.s.) on spruce (Picea abies) and pine (Pinussylvestris) using 23 homokaryotic haploid isolates was performed. The virulence of the isolates wasmeasured as lesion length in the phloem and fungal growth within the sapwood followinginoculations in the stem of 2-year-old pine and spruce seedlings. The fungal isolates were sequencedto between 2.6× and 12.6× coverage using the Illumina Genome Analyzer. This data set yielded33,018 single nucleotide polymorphisms (SNPs), with a minor allelic frequency of at least two out of23. These loci were present in all isolates. SNPs and mean values for each virulence trait were usedfor the association study. Twelve SNP markers distributed on seven contigs were found to besignificantly associated with fungal virulence (P< 0.0001). These regions were characterized forlinkage disequilibrium (LD) and gene contents. The LD blocks in these regions ranged between 1.2and 31.2 kb when present. Nine genes encoding calcineurin, acetylglutamate kinase/synthase,cytochrome P450 monooxygenase, serine carboxypeptidase, quinone oxidoreductase (ToxD), twoflavin-containing monooxygenases, exopolyphosphatase and a Swi5 transcription factor wereidentified as candidates for virulence.

Published in

ISBN: 978-88-6655-352-6
Publisher: Firenze University Press


Proceedings of the XIII International Conference on Root and Butt Rot of Forest Trees.