Characterisation of GST genes from the Chinese white pine beetle Dendroctonus armandi (Curculionidae: Scolytinae) and their response to host chemical defence

Abstract

The increased transcription levels of GST genes suggested that they have some relationship with the detoxification of terpenoids that are released by host trees. The mediating oxidative stress that is caused by monoterpene might be the main role of the bark beetle GSTs.

Gene family expansion of pinewood nematode to detoxify its host defence chemicals

“…We observed up‐regulation of genes in the B. xylophilus ‐specific clade of FMOs (FMO‐5, FMO‐10). Although many GST (Dai et al, ), UGT (Ono & Tsuruoka, ), ABC transporter (Yazaki, ) and cuticle collagen (Bongers, ) gene families are also associated with metabolism of xenobiotics, these gene families were not expanded in B. xylophilus compared to xenobiotic terpene metabolism pathway genes. Previous studies have found that certain genes in the α‐pinene‐treated samples were up‐regulated, including CYPs, SDRs, UGTs and GSTs (Li et al, ).…”

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

“…The use of very similar experimental strategies with the other detoxifying enzymes (P450 enzymes and GSTs) of D. armand enabled the identification of CarE genes probably involved in similar functions . DaCarE s maintain higher transcript levels in larvae and adults that need to hydrolyze a host secondary metabolite or degrade an odorant .…”

“…For instance, monoterpenoids from Euphorbia ebracteolata showed an inhibitory effect against human carboxylesterase‐2 (hCE‐2) using a fluorescence bioassay in vitro . However, monoterpene treatment for Scolytidea focuses on CYP gene inducement . Upon treatment with monoterpenes and turpentine, DaCarE1 , DaCarE2 and DaCarE5 were downregulated in adults, unlike another two detoxifying enzymes, and there is no specificity for xenobiotics in them.…”

“…Because insecticides against bark beetle had not been used in our sampling location, host chemical defense was the main pressure acting on these beetles. Detoxifying enzymes of bark beetles were the main research focus for understanding the molecular mechanism behind the bark beetle behaviors of host selection and colonization …”

“…In this study, we used RNA‐Seq to identify CarEs from the Chinese white pine beetle, detected the sequence structure and homology of eight CarEs, and analyzed their transcript levels at different development stages and under different treatments. The experimental strategy was very similar to that used for P450s and GSTs in D. armandi with monoterpenes (α‐pinene, β‐pinene, 3‐carene and limonene) as the main stimulus . We aimed to explore the characteristics of Chinese white pine beetle carboxylesterases genes and their transcript levels during detoxification of host major monoterpenes in early host colonization.…”