Species, distribution and spore density of Heterobasidion in Canada

Citation

Ac12: (Abstract) Bérubé, J. A., Potvin A., D. Stewart, P. N. Gagné, J. P. Ponchart, Phelan J., A. Varga, D. James, É. D. Tremblay, M.-O. Duceppe, T. Kimoto, and G. J. Bilodeau. 2018. Species, distribution and spore density of Heterobasidion in Canada. In LIFE+ ELMIAS Ash and Elm, and IUFRO WP 7.02.01 Root and Stem Rots Conference (LIFE-IUFRO), edited by R. Vasaitis. 26 August - 1 September 2018, Uppsala and Visby, Sweden: Swedish University of Agricultural Sciences, Uppsala.

Plain language summary

Heterobasidion irregulareis a fungus causing a root disease capable of killing large trees. Infection probability is proportional to the density of its aerial basidiospores infecting freshly cut red pine stumps. We quantified for the first time H. irregulareaerial basidiospore density in southern Quebec and deposition rate along a southern Quebec transect. Spore counts from automated rotary arm spore collectors were determined using a ribosomal ITS TaqMan real-time PCR detection assay.Cumulative spore deposits on a 30 cm stump were estimated to be highest in the infected plantation with 2.01 spores per stump, 0.46 spore at a 500 m distance and 0.19 at 5km. On the transect study, total count was 706.3 spores in Harrington, rapidly decreasing with an eastward direction on the transect. With few exceptions, weekly spore depositions at all sites other than Harrington were greatly below 0.2 per m-2h-1. In a metagenomic study using Ion Torrent sequencing of aerial spores revealed presence of H. annosum s.s., in 7 samples from the provinces of Quebec and Ontario. It also showed presence of H. abietinum/H. parviporum DNA reads in soil samples and insect traps from British Columbia. A similar study using Illumina sequencing from local and imported ornamental nursery plants samples from British Columbia revealed the presence of Heterobasidion irregulare and H. occidentaleDNA, H. irregularehaving been mentioned only once before as present in BC. Surprisingly H. irregularecomprising 86% of the HeterobasidionDNA reads and more commonly found (13/15 samples) than H. occidentale(10/15 samples).These results will be discussed in a North American context.

Abstract

Heterobasidion irregulareis a fungus causing a root disease capable of killing large trees. Infection probability is proportional to the density of its aerial basidiospores infecting freshly cut red pine stumps. We quantified for the first time H. irregulareaerial basidiospore density in southern Quebec and deposition rate along a southern Quebec transect. Spore counts from automated rotary arm spore collectors were determined using a ribosomal ITS TaqMan real-time PCR detection assay.Cumulative spore deposits on a 30 cm stump were estimated to be highest in the infected plantation with 2.01 spores per stump, 0.46 spore at a 500 m distance and 0.19 at 5km. On the transect study, total count was 706.3 spores in Harrington, rapidly decreasing with an eastward direction on the transect. With few exceptions, weekly spore depositions at all sites other than Harrington were greatly below 0.2 per m-2h-1. In a metagenomic study using Ion Torrent sequencing of aerial spores revealed presence of H. annosum s.s., in 7 samples from the provinces of Quebec and Ontario. It also showed presence of H. abietinum/H. parviporum DNA reads in soil samples and insect traps from British Columbia. A similar study using Illumina sequencing from local and imported ornamental nursery plants samples from British Columbia revealed the presence of Heterobasidion irregulare and H. occidentaleDNA, H. irregularehaving been mentioned only once before as present in BC. Surprisingly H. irregularecomprising 86% of the HeterobasidionDNA reads and more commonly found (13/15 samples) than H. occidentale(10/15 samples).These results will be discussed in a North American context.

Publication date

2018-08-26

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