Canadian Forest Service Publications
Heterobasidion populations in Canada are separated geographically and resemble H. irregulare and H. occidentale based on sequence analysis of housekeeping genes. 2011. Li, X.; Shamoun, S.F.; Nie, J.; Hammill, D.L.; De Boer, S.H. Page 319 in Plant Canada Conference Proceedings, July 17-21, 2011, Halifix, Nova Scotia. Plant Canada.
Available from: Pacific Forestry Centre
Catalog ID: 32645
Heterobasidion annosum species complex, the causal agent of root and butt rot of coniferous trees, is comprised of five fungal species. H. annosum, H. parviporum and H. abietinum are widely distributed in European countries while H. irregulare and H. occidentale occur in different regions of North America. Morphological differentiation among species remains a long standing challenge for classification of these plant pathogenic fungi despite recent progress. In this study, we collected 26 isolates from the provinces of British Columbia and Ontario. Eight housekeeping gene markers were selected for genetic analysis of heterobasidion populations isolated in Canada. Specific gene fragments were amplified and purified, and sequenced for each of the fungal isolates. The targeted genes were transcription factor, glutathione-S-transferase, internal transcribed spacer region, NADH dehydrogenase (subunit 5), elongation factor 1 (α subunit), ATP synthase (subunit 6), glyceraldehyde 3-phosphate dehydrogenase and mitochondrial rDNA insertion element. Phylogenetic analysis of sequences from the 26 isolates along with those from 226 other strains isolated in Europe, Asia, and North America, based on the partial elongation factor sequences, revealed that isolates from British Columbia formed a cohesive cluster resembling H. occidentale, and shares high sequence homology with isolates from regions west of the Rocky Mountains, such as California and Idaho in the USA. Another 16 isolates from regions east of the Rocky Mountains exhibited various degrees of sequence variation, and shared a close phylogenetic relationship with H. irregulare isolates from Quebec and Ontario in Canada, and Montana, Georgia, and Alabama in the USA. We are currently analysing the sequence data obtained from the additional housekeeping genes of the 26 isolates for multi-loci sequence typing.