The cytochromes P450 of Grosmannia clavigera: Genome organization, phylogeny, and expression in response to pine host chemicals

Grosmannia clavigera is a fungal associate of the mountain pine beetle (Dendroctonus ponderosae) and a pathogen of lodgepole pine (Pinus contorta) that must overcome terpenoid oleoresin and phenolic defenses of host trees. G. clavigera responds to monoterpene influx with complementary mechanisms that include export and the use of these compounds as a carbon source. Cytochromes P450 (CYPs) may also be involved in the metabolism of host defense compounds. We have identified and phylogenetically classified G. clavigera CYPs (CYPome). We show that although the G. clavigera CYPome has contracted in evolution, certain CYP families have expanded by duplication. We analyzed RNA-seq data for CYP expression following treatment with terpenes and pine phloem extracts to identify CYPs potentially involved in detoxification of these pine defense compounds. We also used transcriptome analysis of G. clavigera grown on monoterpenes, triglycerides or oleic acid as a carbon source to identify up-regulated CYPs that may be involved in the utilization of these compounds to support fungal growth. Finally, we identify secondary metabolite biosynthetic gene clusters that contain CYPs, and CYPs in clusters that may be involved in conversion of host chemicals.

► Grosmannia clavigera has a small but specialized cytochrome P450 content (CYPome).
► RNAseq reveals CYPs that may be involved in terpenoid and/or phenolic detoxification.
► Different CYPs are expressed with monoterpenes or oleic acid as carbon sources.
► CYPs are part of induced secondary metabolite and detoxification gene clusters.