title: Cloning and Expression of Multiple Cytochrome P450 Genes: Induction by Fipronil in Workers of the Red Imported Fire Ant (Solenopsis invicta Buren).
abstract: Both exogenous and endogenous compounds can induce the expression of cytochrome P450 genes. The insect cytochrome P450 genes related to insecticide resistance are likely to be expressed as the "first line of defense" when challenged with insecticides. In this study, four cytochrome P450 genes, SinvCYP6B1, SinvCYP6A1, SinvCYP4C1, and SinvCYP4G15, were firstly isolated from workers of the red imported fire ant (Solenopsis invicta) through rapid amplification of cDNA ends (RACE) and sequenced. The fipronil induction profiles of the four cytochrome P450 genes and the two previously isolated CYP4AB1 and CYP4AB2 were characterized in workers. The results revealed that the expression of SinvCYP6B1, SinvCYP6A1, CYP4AB2, and SinvCYP4G15, increased 1.4-fold and 1.3-fold more than those of acetone control, respectively, after 24 h exposure to fipronil at concentrations of 0.25 μg mL-1 (median lethal dose) and 0.56 μg mL-1 (90% lethal dose), while no significant induction of the expression of CYP4AB1 and SinvCYP4C1 was detected. Among these genes, SinvCYP6B1 was the most significantly induced, and its maximum expression was 3.6-fold higher than that in acetone control. These results might suggest that multiple cytochrome P450 genes are co-up-regulated in workers of the fire ant through induction mechanism when challenged with fipronil. These findings indicated that cytochrome P450 genes play an important role in the detoxification of insecticides and provide a theoretical basis for the mechanisms of insecticide metabolism in the fire ant.
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China.|College of Natural Resources and Environment, Henan Institute of Science and Technology, Xinxiang 453003, P.R. China.
authors.forename: Baizhong
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Entomology, China Agricultural University, Beijing 100193, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China.
authors.forename: Rukun
authors.initials: R
authors.lastname: Cui
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510642, P.R. China.
authors.forename: Xinnian
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Department of Entomology, China Agricultural University, Beijing 100193, P.R. China.
authors.forename: Xiwu
authors.initials: X
authors.lastname: Gao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001000:Ants / Q000235:genetics*; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D018076:DNA, Complementary; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011720:Pyrazoles / Q000494:pharmacology*; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D011720:Pyrazoles; D003577:Cytochrome P-450 Enzyme System; C082360:fipronil