Dothistroma septosporum (= pini) is a fungal pathogen belonging to the group ascomycota. It is an important pathogen on many species of pine worldwide. The fungus colonizes pine needles, and as a part of its life cycle produces dothistromin, a mycotoxin believed to be responsible for the disease, resulting in red banding on the needles, and eventually causing death of the needle and defoliation of the tree. The current disease outbreak in British Columbia is unique due to the severity and extent, as well as the host being a native Pinus species. These circumstances have not been previously encountered in northern countries. The favourable conditions for disease, as well as the existence of the teleomorph in British Columbia, may have led to a case where sexual reproduction has allowed for rapid evolution of the pathogen population. Rapid evolution may have given rise to a more virulent strain of the fungus itself. Knowing the dynamics of the pathogen populations in respect to how it changes with ecosystem differences, what conditions cause rapid evolution, and how it spreads, aids forest managers and silviculture planning. Ecosystem characteristics conducive to disease spread can be avoided for lodgepole pine, or other low risk strategies can be employed to reduce disease severity and spread. Therefore, the purpose of this study is to explore the population genetic structure of Dothistroma septospora populations in Northwest British Columbia, to relate population structure to the contributions of reproductive strategies, forest types and to current forest practices, and to relate population genetic structure to toxin producing abilities of the pathogen.
Dale, Angie, Lewis, Kathy J.; Woods, Alex J.. 2006. Genetic variation in the foliar pathogen Dothistroma septospora and relationship to toxin production. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2006MR297