Disentangling Detoxification: Gene Expression Analysis of Feeding Mountain Pine Beetle Illuminates Molecular-Level Host Chemical Defense Detoxification Mechanisms

Abstract

The mountain pine beetle, Dendroctonus ponderosae, is a native species of bark beetle (Coleoptera: Curculionidae) that caused unprecedented damage to the pine forests of British Columbia and other parts of western North America and is currently expanding its range into the boreal forests of central and eastern Canada and the USA. We conducted a large-scale gene expression analysis (RNA-seq) of mountain pine beetle male and female adults either starved or fed in male-female pairs for 24 hours on lodgepole pine host tree tissues. Our aim was to uncover transcripts involved in coniferophagous mountain pine beetle detoxification systems during early host colonization. Transcripts of members from several gene families significantly increased in insects fed on host tissue including: cytochromes P450, glucosyl transferases and glutathione S-transferases, esterases, and one ABC transporter. Other significantly increasing transcripts with potential roles in detoxification of host defenses included alcohol dehydrogenases and a group of unexpected transcripts whose products may play an, as yet, undiscovered role in host colonization by mountain pine beetle.

Proteomics Indicators of the Rapidly Shifting Physiology from Whole Mountain Pine Beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae), Adults during Early Host Colonization

“…Calreticulin increased by the same magnitude in MPB larvae as they developed in spring [25]. The transcript of this protein also increased in host-exposed males (YQE10054, [51]) and microarray analysis of Ips pini midgut tissue also indicated an induction with feeding [35]. Insect calreticulin has also been shown to be part of the response to microorganisms [54].…”

“…Both HSPs were also found to increase on the transcriptome level (YQE07729, [51]). Many stressors illicit a HSP response, including heat, desiccation, radiation, and chemical compounds [52].…”

Isolation of CarE genes from the Chinese white pine beetle Dendroctonus armandi (Curculionidae: Scolytinae) and their response to host chemical defense

“…The only CarE from Dendroctonus was studied from D. ponderosae . After feeding with fresh phloem from the host, significantly changed transcripts of the DpCarEs were detected by RNA‐Seq in females . Only DaCarE3 was significantly upregulated in fed adults at 12 h and that may have roles in host chemical detoxification.…”

“…Although CarEs have been discovered by transcriptome and genome mining in Tomicus yunnanensis and Dendroctonus ponderosae , none have been characterized in bark beetles. A large‐scale gene expression analysis (RNA‐seq) of mountain pine beetle male and female adults that were either starved or fed in pairs on host conifer tissues shows that some esterase transcripts increased significantly after feeding on host tissue …”

P450s in Plants, Insects, and Their Fungal Pathogens

“…aegypti induced with atrazine (herbicide), fluoranthrene (polycyclic aryl hydrocarbon), propoxur, permethrin, and imidaclprid (insecticides) [295], A. funestus life stages [321], A. gambiae chemosensory appendages [322], D. ponderosae life stages, tissues and sexes [323][324][325], Ips typographus (spruce bark beetle) antennae [324], as well as comparative analyses in insecticide-susceptible, -resistant, and -selected strains ( Cimex lectularis (bed bug), [326]; A. gambiae, [327,328])…”