A naturally-occurring resistance gene against the spruce bud worm: genomic characterization, and applications in Canadian tree breeding and pest management

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The spruce budworm (SBW) Choristoneura fumiferana (Clem.) is among the most destructive defoliating forest pests of eastern North America. Tree deaths and reduced growth caused losses of 0.38 billion cubic meters of wood during the last major SBW outbreak (1973-1987). Areas of heavy SBW defoliation have increased exponentially in eastern Canada since 2007. Three other species of SBW are of concern in western Canada. Planting spruce seedlings that have durable SBW resistance is a desirable strategy to reduce losses of forest supply and renew our timberlands. However, critical knowledge and know-how for reaching this goal have been lacking. We recently discovered naturally-occurring resistance to the SBW in white spruce (Picea glauca). This opens the doors to major innovations in this important area of forest pest management and natural resource protection. The accumulation of two phenolic compounds (piceol and pungenol) appears to explain this phenotypic variation in SBW resistance. Expression of a single beta-glucosidase candidate gene is strongly correlated with these traits. We propose to use accumulation of these compounds and expression of the beta-glucosidase gene as resistance biomarkers for developing genetically resistant trees and an approach for evaluating the vulnerability of natural and managed forests. Opportunities for breeding SBW resistant trees will be developed in major spruce species from eastern and western Canada. True fir and Douglas-fir will also be studied. Industry and public sector supporting organizations will contribute to the research and the translation of research results into practical applications, for the development of environmental and economic benefit to Canada. We will also investigate the molecular and biochemical mechanisms related to SBW resistance and study the impacts of the phenolic compounds on insect development and selective evolution. Our team combines internationally recognized and complementary expertise to support this interdisciplinary and innovative research. Anticipated outcomes will result in new tools and techniques for identifying higher value planting stocks and for maximizing the use of our forest land for supply of fibre, wood and energy resources.