Dothistroma septosporum (= Dothistroma pini) is a foliar pathogen on many species of pine around the world. Recently there has been a large outbreak of Dothistroma in northwestern British Columbia that has been causing concern due to the extent of the outbreak as well as the severity of damage, which includes some stands with almost 100% mortality. Several factors may be contributing to the extent and severity of the outbreak. These include changing weather patterns, an increase in host availability, or more virulent strains of Dothistroma produced by sexual reproduction patterns of the fungus. The effects from this outbreak, and future outbreaks include mortality of pine in plantations, reforestation expenses, and reduced timber yields due to growth reduction from repeated years of defoliation. In British Columbia, the sexual stage of the fungus is present, which may lead to an increase in genetic diversity. The levels of genetic diversity may correlate with increased virulence or dothistromin production by the fungus. As this toxin has been shown to have human mutagenic properties, it is important to know what risk it poses to forest workers as well as to our forests. Therefore, the objectives of this study are: 1) To explore the genetic variation of Dothistroma septosporum in northwestern British Columbia as it relates to location and environment; 2) To determine if the amount of dothistromin produced by strains of D. septosporum correlates to the genetic diversity present within the populations of fungi in northwestern British Columbia; and 3) To determine if the genetic variation and/or relatedness of Dothistroma septosporum is comparable or higher in the northwest portion of British Columbia in relation to other parts of the world. Approximately 30 sites across 3-5 biogeoclimatic subzones (Interior Cedar Hemlock and Sub Boreal Spruce) will be sampled, eight trees per site and several branches per tree. Microsatellite markers and Amplified Fragment Length Polymorphisms (AFLP) will be used to compare genetic variation at different spatial scales, including some international samples. Dothistromin assessments on selected isolates will be carried out with collaborators from New Zealand.
Kathy Lewis, Angie Dale.
Lewis, Kathy J., Dale, Angie. 2005. Genetic variation in the foliar pathogen Dothistroma Septosporum and relationship to toxin production: annual technical report. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report