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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Aquatic Animal Health Strategies

Location: Aquatic Animal Health Research

Title: Transcriptional analysis of four family 4 P450s in a Puerto Rico strain of Aedes aegypti (Diptera: Culicidae) compared with an Orlando strain and their possible functional roles in permethrin resistance

Authors
item Reid, William
item Thornton, Anne -
item Wei Pridgeon, Yuping
item Becnel, James
item Tang, Fang -
item Estep, Alden -
item Clark, Gary
item Allan, Sandra
item Liu, Nannan -

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 1, 2014
Publication Date: May 1, 2014
Citation: Reid, W.R., Thornton, A., Wei Pridgeon, Y., Becnel, J.J., Tang, F., Estep, A., Clark, G.G., Allan, S.A., Liu, N. 2014. Transcriptional analysis of four family 4 P450s in a Puerto Rico strain of Aedes aegypti (Diptera: Culicidae) compared with an Orlando strain and their possible functional roles in permethrin resistance. Journal of Medical Entomology. 51(3):605-615.

Interpretive Summary: A field mosquito strain of Aedes aegypti was collected from Puerto Rico (PR) in October 2008. Based on LD50 values by topical application, the PR strain was 73-fold resistant to permethrin pesticide compared to a susceptible Orlando strain of mosquito Aedes aegypti. In the presence of piperonyl butoxide (PBO), the inhibitor of cytochrome P450, the resistance of PR mosquito to permethrin was reduced to 15-fold, suggesting that cytochrome P450-mediated detoxification was involved in the resistance. To determine which cytochrome P450s might play a role in the resistance to permethrin, the transcriptional levels of 164 cytochrome P450 genes in the PR strain were compared to that in the Orlando strain. Of the 164 cytochrome P450s, 33 were significantly up-regulated, including four CYP4 P450s. When exposed to 5 µg/vial permethrin, the transgenic Drosophila melanogaster expressing CYP4D24 or CYP4J15v1 had the highest survival rate (53% to 73%), followed by flies expressing CYP4H29 or CYP4H33 (29% or 11%, respectively). However, none of the control flies survived the permethrin exposure at the same concentration. When the concentration of permethrin was increased to 10 µg/vial, the transgenic D. melanogaster expressing CYP4D24 had a survival rate of 40%, whereas the rest of the flies had a survival rate less than 5%. Taken together, our results suggest that CYP4D24 might play an important role in cytochrome P450-mediated resistance to permethrin.

Technical Abstract: A field strain of Aedes aegypti was collected from Puerto Rico (PR) in October 2008. Based on LD50 values by topical application, the PR strain was 73-fold resistant to permethrin compared to a susceptible Orlando strain. In the presence of piperonyl butoxide (PBO), the resistance of Puerto Rico strain of Ae. aegypti was reduced to 15-fold, suggesting that cytochrome P450-mediated detoxification is involved in the resistance of the PR strain to permethrin. To determine which cytochrome P450s might play a role in the resistance to permethrin, the transcriptional levels of 164 cytochrome P450 genes in the PR strain were compared to that in the Orlando strain. Of the 164 cytochrome P450s, 33 were significantly (p<0.05) up-regulated. To determine whether up-regulation of cytochrome P450s had a functional role in permethrin resistance, transgenic Drosophila melanogaster lines over-expressing four family 4 P450 genes were generated, and their ability to survive exposure to permethrin was evaluated. When exposed to 5 µg/vial permethrin, the transgenic D. melanogaster expressing CYP4D24 or CYP4J15v1 had the highest survival rate (53% to 73%), followed by flies expressing CYP4H29 or CYP4H33 (29% or 11%, respectively). However, none of the control flies survived the permethrin exposure at the same concentration. When the concentration of permethrin was increased to 10 µg/vial, the transgenic D. melanogaster expressing CYP4D24 had a survival rate of 40%, whereas the remaining flies had a survival rate less than 5%. Taken together, our results suggest that CYP4D24 might play an important role in cytochrome P450-mediated resistance to permethrin.

Last Modified: 7/30/2014
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