Heterobasidion annosum sensu stricto Genome Sequencing. Heterobasidion annosum

Heterobasidion annosum is a necrotrophic pathogen that causes root rot to conifers in the Northern Hemisphere resulting in severe economic losses for forest owners. Based on 33,018 single nucleotide polymorphisms (SNP) in 23 haploid isolates, we conducted a genome-wide association (GWA) study analysing the virulence of H. annosum on Picea abies and Pinus sylvestris. Twelve SNP markers distributed on seven contigs were associated with virulence (P<0.0001). Four of the contigs harbour known virulence genes from other fungal pathogens and the remaining three novel candidate genes. Two contigs link closely to virulence regions recognized previously by QTL mapping in the congeneric hybrid H. irregulare × H. occidentale. Our study demonstrates the efficiency of GWA studies for dissecting important complex traits of non-model haploid organisms.