Grant: Discovery Grants Program - Individual

Conifers are the dominant trees of the Canadian forest landscape and the most important trees for the forest industry. Due to climate change, conifer forests are increasingly threatened by outbreaks of insect pests. There is an urgent need to understand on a genomic and functional level the natural defense mechanisms of conifers, in order for breeding programs to deliver trees with durable resistance for future, climate resilient forests. My long-term research program is at the global forefront of genomic discovery and functional characterization of conifer defense systems*. Conifers have evolved complex chemical and physical defenses. Oleoresin terpenes and phenolic metabolites (e.g. acetophenones) are major chemical defenses. They are comprised of hundreds of different metabolites, with highly variable profiles between and within different conifer species. Physical defenses include specialized cell-types and anatomical structures, such as lignified stone cells and resin ducts. Chemical and physical defenses can be induced by insects and act synergistically. Two large classes of enzymes, terpene synthases and cytochromes P450, generate the large diversity of oleoresin terpenes. Only two genes of acetophenone biosynthesis are known. Terpenes are biosynthesized in specialized resin duct cells. Resin ducts, stone cells, terpenes and phenolics provide strong protection against most insects. However, during outbreaks some highly destructive pests can overcome these defenses. The proposed project builds on the foundation of my long-term, highly original and innovative research program that integrates in a systems biology approach work on (i) conifer and forest health genomics, (ii) conifer defense systems, and (iii) terpene and phenolic biosynthetic systems. The overall goal of my program is a genomics-informed, functional understanding of complex conifer defense systems with applications in forest health. The four specific objectives of this proposal are to comprehensively understand: (1) Chemical diversity and plasticity of terpene defenses (2) Mechanisms of the induced oleoresin defense system (3) Genomic & biochemical underpinnings of acetophenone defenses (4) Effects of environmental factors on chemical and physical defense systems. The project focuses on spruces, which are the most reforested conifers in Canada, and two major pests, weevils and budworms. Spruce breeders identified genotypes that are resistant or susceptible to these pests. This project will deliver novel insights into the underlying defense mechanisms and their genomic and biochemical underpinnings. It will address long-standing questions and new hypotheses on conifer defense systems. It will deliver fundamental knowledge and inform practical applications in collaborations with tree breeding programs. The research will provide exceptional and inclusive graduate student training. *see my Tansley Review, Ann Rev Plant Biol and PCE review included as samples