The role of terpene synthases in the direct and indirect defense of conifers against insect herbivory and fungal pathogens

Abstract

13.6 Conclusion: The results described in this brief review provide fertile ground for future analyses of the presence or absence or sequence variation of certain TPS genes in particular species or within populations of conifers and of overall expression patterns of TPS and other genes in the pathways affecting terpenoid biosynthesis and ultimately resin composition, volatile emission, and defense against insects and pathogens in conifers. The multigene TPS families in conifers can be explored for development of SNPs and other markers potentially associated with variation in defenses and resistance to insect pests or pathogens in conifers. Such work ought to be carried out in terms of what is already known about tree biochemical, anatomical, and physiological responses, terpenoid toxicity, insect behavior before and during colonization of host trees, and differential host preferences. An approach that takes into account the multigenic nature of terpenoid defenses in conifers will doubtless shed more light on the coevolutionary relationship between bark beetles and their host trees, and will provide new tools for monitoring and managing these economically and ecologically important conifer-insect interactions.