Circadian control of permethrin-resistance in the mosquito Aedes aegypti.
Daily fluctuation of permethrin-resistance was found in adult mosquito Aedes aegypti, the major vector of dengue viruses in Taiwan. We hypothesized there is a relationship between resistance and the circadian clock. To test our hypothesis we correlated changes in the knock-down time (KT(50)) response to permethrin with the expression of the pyrethroid-resistant gene CYP9M9 and the clock gene period (per) during a 12:12h photoperiodic cycle. Rhythmic expression of per peaked at early scotophase of the light-dark cycle and at early subjective night in constant darkness. The values of KT(50) and the expression of CYP9M9 also exhibited circadian rhythms in both susceptible and permethrin-resistant mosquito strains, from which we inferred a link to the circadian clock. The KT(50) was significantly longer in the light than in the dark phase, and the level of CYP9M9 mRNA was maximal in early scotophase, dropped to a minimum in the midnight and then slowly increased through the photophase. Existence of a clock control over mosquito sensitivity to permethrin was further indicated by reduced expression of CYP9M9 and reduced mosquito resistance to permethrin after temporal silencing of the per gene. These data provide the first evidence on the circadian control of insect resistance to permethrin.
Yang
Yung-Yu
YY
Department of Plant Medicine, National Pingtung University of Science and Technology, Taiwan.
Liu
Yun
Y
Teng
Hwa-Jen
HJ
Sauman
Ivo
I
Sehnal
Frantisek
F
Lee
How-Jing
HJ
D000330:Aedes / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D020868:Gene Silencing; D007303:Insect Vectors / Q000378:metabolism / Q000502:physiology*; D007305:Insecticide Resistance / Q000502:physiology*; D007928:Lethal Dose 50; D056950:Period Circadian Proteins / Q000378:metabolism; D026023:Permethrin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013624:Taiwan
D017931:DNA Primers; D056950:Period Circadian Proteins; D026023:Permethrin; D003577:Cytochrome P-450 Enzyme System