Identification and Expression of a β-actin Gene from Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae)

CHARACTERIZATION AND EXPRESSION PROFILES OF FIVE POSSIBLE CYTOCHROME P450 GENES FROM Liposcelis entomophila (ENDERLEIN) (PSOCOPTERA: LIPOSCELIDIDAE)

In this study, the cDNAs of five cytochromes P450 genes (named CYP345P1, CYP358B1, CYP4FD2, CYP4CD2, and CYP6JN1) contained open reading frames from 1,500 to 1,554 nucleotides that encoded 499 to 517 amino acids were cloned from the psocid Liposcelis entomophila. They are characterized by predicted molecular weights from 57.67 to 59.64 kDa and theoretical isoelectric points of 5.57-9.07. Quantitative real-time PCR analysis showed these five genes were expressed at all tested developmental stages and higher expressions were observed in adults. CYP358B1 was expressed at higher levels in egg and adult compared to the larval stages. mRNA abundances of five genes were detected in both sexes and were relatively more abundant in adult females than in adult males. Synergism bioassay showed that the synergic ratio was 2.20 and 2.45 when insects were treated with the mixture of deltamethrin or malathion with the synergist piperonyl butoxide (PBO). Because PBO induces cytochrome P450s in some insects, this suggested to us that cytochromes P450 might participate in detoxification of these insecticides. The transcripts of the five cytochromes P450 genes in adult psocids could be induced to the highest level at 12 h after the exposure to malathion. After exposure to deltamethrin, CYP358B1 reached maximum expression at 24 h. The maximum expression of the other four genes occurred at 36 h. Treatments with the carbamate propoxur did not influence transcription of the cytochromes P450 gene. The induction profiles suggested that these five cytochrome P450 genes may be associated with deltamethrin and malathion metabolism in psocids.

Transcription and induction profiles of three novel P450 genes in Liposcelis bostrychophila (Psocoptera: Liposcelididae)

The cDNAs of three novel P450 genes, CYP4CB1, CYP4CC1, and CYP4CD1 (GenBank accessions EU979550, EU979549, and EU979551, respectively), were sequenced and characterized from the psocid Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae). CYP4CB1, CYP4CC1, and CYP4CD1 contain open reading frames of 1533, 1512, and 1536 nucleotides that encode 511,504, and 512 amino acid residues, respectively. The putative proteins of CYP4CB1, CYP4CC1, and CYP4CD1 show predicted molecular mass of 59.65, 58.87, and 59.71 kDa, with a theoretical isoelectric point of 6.59, 8.80, and 8.84, respectively. The N-terminal transmembrane domain was only found in CYP4CB1 suggested it is a typical microsomal P450. Phylogenetic analysis showed a close relationship of CYP4CB1, CYP4CC1, and CYP4CD1 with CYP4AW1, CYP4L4, and CYP4E2. Quantitative real-time reverse transcriptase-polymerase chain reaction indicated that these three genes were expressed at all tested developmental stages. In addition, the highest expression occurred in the adult stage, which suggested that these three P450 genes may play important roles in adulthood. The transcripts of CYP4CB1 and CYP4CC1 in adult psocids could be induced to the highest level at 36 and 24 h after the exposure to deltamethrin and paraoxon-methyl (50% lethal concentration [LC50]), respectively, whereas CYP4CD1 remained unchanged. CYP4CD1 transcripts, however, increased rapidly at 8 h after aldicarb (LC50) induction and reached the peak at 36 h. The induction profiles of the three P450 genes suggested that CYP4CB1 and CYP4CC1 are possibly associated with deltamethrin and paraoxonmethyl metabolism in psocids, whereas CYP4CD1 is probably involved in aldicarb metabolism. However, our assumption needs to be further verified by recombinant protein expression of these proteins as well as RNA interference of these genes.