Adaptation of the pine fungal pathogen Grosmannia clavigera to monoterpenes: Biochemical mechanisms revealed by RNA‐seq analysis

Abstract

SummaryThe blue stain fungus Grosmannia clavigera (G. clavigera) is a pathogen of pines that can tolerate monoterpenes in oleoresin. Grosmannia clavigera has developed several mechanisms to cope with the host's monoterpene defence: a monoterpene efflux system mediated by an ABC transporter and enzymes that utilize or modify monoterpenes. In this study, we integrated two expression data sets based on a match between their multidimensional distributions. The data sets are raw RNA-seq and already processed transcriptome expression data with partially matching biological conditions. As a result, several new regulatory mechanisms, including the upregulation of the stress response and the developmental process at early-time-point terpene treatment, were involved in the adaptation of G. clavigera to monoterpenes and were supported by both data sets. In addition, several genes related to terpenoid modification were upregulated within 36 h (in rich media) and 7 days (in poor media) of terpene treatment. These results led us to the assumption that G. clavigera used terpenes as an energy source within 7 days when no other energy source was available, while within 36 h of terpene treatment on rich media these genes took part in terpene detoxification. As the G. clavigera genome is not well annotated, we performed detection of new putative transcripts as genome fragments enriched by read mapping. Several newly detected transcripts annotated as putative retrotransposons were upregulated mostly under early-time-point terpene treatment, while others annotated as putative ribonuclease and protease were downregulated mostly during early-time-point terpene treatment. Based on these results, it can be hypothesized that these new transcripts could play a role in previously unidentified G. clavigera terpene response regulatory mechanisms. Overall, this study identified gene expression regulations supported by two data sets as well as new putative transcripts related to new processes that might be important for G. clavigera tolerance to terpenes.

The host generalist phytopathogenic fungus Sclerotinia sclerotiorum differentially expresses multiple metabolic enzymes on two different plant hosts

“…S. sclerotiorum , for example, is known to metabolise phytoalexins produced by crucifer hosts during infection, effectively converting them into smaller non-toxic molecules 8 . Similarly, the fungal phytopathogen Grosmannia clavigera , which infects pines, is thought to utilise a variety of mechanisms to detoxify host-produced terpenes 9 . These mechanisms may include modification of the terpenes to less toxic molecules and transporter-based efflux 46 .…”

Comparative genomic analysis of pleurotus species reveals insights into the evolution and coniferous utilization of Pleurotus placentodes

“…Other stress resistance-related metabolisms were also identified, including chemokine signaling pathway, ABC transporters, Fc gamma R-mediated stress, aminoacyl tRNA biosynthesis, glycine, serine, and threonine metabolism. These have been shown to be related to microbial infection (Chensue, 2001), monoterpene resistance (Wang et al, 2013;Kligun et al, 2017), and exogenous oxidative stress (Qi et al, 2019).…”

Phylogeny of Leptographium Qinlingensis Cytochrome P450 Genes and Their Expression When Grown on Different Media or Treated With Terpenoids

“…Thus, cytochrome P450 enzymes that are highly induced by terpenes and metabolize or utilize monoterpenes are considered the major mechanisms that enable fungal resistance to monoterpenes (Lah et al 2013;Wang et al 2014). The nutrition of culture media could have an effect on the tolerance of G. clavigera to terpenes (Kligun et al 2017).…”