Terpenoid metabolite profiling in Sitka spruce identifies association of dehydroabietic acid, (+)-3-carene, and terpinolene with resistance against white pine weevil

Abstract

The white pine weevil ( Pissodes strobi Peck) is an important insect pest in the Pacific Northwest that attacks the apical stem leaders of spruce ( Picea spp.) causing damage to tree form, growth, and stand development. Because of attacks by weevils, Sitka spruce ( P. sitchensis Bong.) is not commonly replanted as a commercial species in coastal British Columbia, despite its economic and ecological importance. In the last decade, the focus of research on Sitka spruce resistance against weevils has moved from silvicultural approaches to breeding for resistance. The British Columbia Ministry of Forests and Range, in collaboration with the Canadian Forest Service, has developed a successful program to screen populations and select tree genotypes for resistance to weevil attack. Part of this effort has been the establishment of clonebanks that contain genotypes from throughout the range of Sitka spruce. For metabolite profiling, using gas chromatography coupled with flame ionization detection or mass spectrometry, we analysed 111 different genotypes to determine the relationship of mono- and di-terpenoid oleoresin compounds with the resistance rating. Dehydroabietic acid, a diterpene, was identified as a strong indicator of resistance. Two monoterpenes, (+)-3-carene and terpinolene, were also associated with resistance in genotypes originating from one of the areas (Haney) in which resistance has been noted.

Evolution of Diterpene Metabolism: Sitka Spruce CYP720B4 Catalyzes Multiple Oxidations in Resin Acid Biosynthesis of Conifer Defense against Insects

“…A major product of CYP720B4 is dehydroabietic acid, which is associated with the resistance of Sitka spruce against its major insect pest, the spruce weevil (Robert et al, 2010). Beyond the general relevance of this work for a fundamental understanding of the evolution of specialized (i.e.…”

“…The same DRAs also reduce feeding damage and growth rates of several sawfly species (Wagner et al, 1983;Schuh and Benjamin, 1984). In Sitka spruce (Picea sitchensis), the accumulation of dehydroabietic acid is associated with resistance against spruce shoot weevil (also referred to as white pine weevil [Pissodes strobi]; Robert et al, 2010). Beyond their roles in conifer defense, DRAs provide a large-volume, renewable resource for industrial bioproducts .…”

“…Pimaric acid was only found in inner stem tissues. It is important to note that the abundance of individual terpenoids can vary across different genotypes of Sitka spruce (Robert et al, 2010).…”

Evolution of Conifer Diterpene Synthases: Diterpene Resin Acid Biosynthesis in Lodgepole Pine and Jack Pine Involves Monofunctional and Bifunctional Diterpene Synthases

“…DRAs are a major (Phillips and Croteau, 1999) and have been implicated, for example, in pine defense to the bark beetle associated fungus O. ips (Kopper et al, 2005) and in Sitka spruce resistance to the white pine weevil (Robert et al, 2010). The committed reactions in DRA biosynthesis are catalyzed by diTPSs Bohlmann, 2006a, 2006b) and cytochrome P450 enzymes (Ro et al, 2005;Hamberger et al, 2011).…”

Plasticity and Evolution of (+)-3-Carene Synthase and (−)-Sabinene Synthase Functions of a Sitka Spruce Monoterpene Synthase Gene Family Associated with Weevil Resistance

“…Previous work (6) explored the monoterpene and diterpene resin acid profiles of Sitka spruce from different geographic regions of the natural distribution where trees displayed strong, intermediate, or weak resistance. Resistance was positively associated with higher levels of the bicyclic monoterpene (ϩ)-3-carene (6). Subsequently, Hall et al (7) used a combination of genomic, target specific proteomic, and biochemical approaches to study the basis of variation of (ϩ)-3-carene levels in two contrasting genotypes of Sitka spruce, resistant genotype H898 trees with relatively high levels of (ϩ)-3-carene and susceptible genotype Q903 trees with trace levels of (ϩ)-3-carene.…”