Two CYP4 genes of the Chinese white pine beetle, Dendroctonus armandi (Curculionidae: Scolytinae), and their transcript levels under different development stages and treatments

Abstract

Bark beetles oxidize the defensive monoterpenes of their host trees both to detoxify them and to convert them into components of their pheromone system. This oxidation is catalysed by cytochrome P450 (CYP) enzymes and occurs in different stages of the insect. We identified two new CYP4 genes in the Chinese white pine beetle (Dendroctonus armandi), and carried out bioinformatic analysis one the full-length nucleic acid sequences and deduced amino acid sequences. Differential expression of the CYP4 genes was observed between sexes, and within these significant differences amongst development stages, fed on phloem of Pinus armandi and exposed to stimuli((±)- α-pinene, (R)-(+)- α-pinene, (S)-(-)-α-pinene, (S)-(-)-β-pinene and (+)-3-carene) at 8 and 24 h, and their interactions were found upon exposure to host monoterpenes. Increased expression of CYP4 genes suggested that they play a role in the detoxification of monoterpenes released by the host trees. The differential transcript accumulation patterns of these bark beetle CYP4 genes provides insight into the ecological interactions of D. armandi with its host pine.

Identification, Characterization and Expression of Methuselah-Like Genes in Dastarcus helophoroides (Coleoptera: Bothrideridae)

“…Significant differences between each group were analyzed by using Tukey’s test [36]; p < 0.05 was considered statistically significant. One-way ANOVA was used for multiple comparisons using SPSS 20.0 (IBM SPSS Statistics, Chicago, IL, USA).…”

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 .…”

“…The expression level of Chinese white pine beetle CarEs were normalized to the expression level of CYP4G55, because it was more stable than 18S rRNA expression after a geNorm calculation . Relative expression of Chinese white pine CarEs were determined using the Ct (ΔΔCT) method .…”

“…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.…”