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Biochemical and Molecular Analysis of Deltamethrin Resistance in the Common Bed Bug (Hemiptera: Cimicidae)

Yoon, Kyong Sup, Kwon, Deok Ho, Strycharz, Joseph P., Hollingsworth, Craig S., Lee, Si Hyeock, Clark, J. Marshall
Journal of medical entomology 2008 v.45 no.6 pp. 1092-1101
Cimex lectularius, deltamethrin, insecticide resistance, resistance mechanisms, esterases, glutathione transferase, enzyme activity, genetic resistance, sodium channels, molecular cloning, complementary DNA, sequence analysis, amino acid sequences, point mutation, New York
This study establishes deltamethrin resistance in a common bed bug, Cimex lectularius L., population collected from New York City (NY-BB). The NY-BB population was 264-fold more resistant to 1% deltamethrin in contact bioassay compared with an insecticide-susceptible population collected in Florida (FL-BB). General esterase, glutathione S-transferase, and 7-ethoxycoumarin O-deethylase activities of NY-BB were not statistically different from those of FL-BB. cDNA fragments that encoded the open reading frame of voltage-sensitive sodium channel α-subunit genes from the FL-BB and NY-BB populations, respectively, were obtained by homology probing polymerase chain reaction (PCR) and sequenced. Sequence alignment of the internal and 5' and 3' rapid amplification of cDNA ends (RACE) fragments generated a 6,500-bp cDNA sequence contig, which was composed of a 6,084-bp open reading frame (ORF) encoding 2,027 amino acid residues and 186-bp 5' and 230-bp 3' untranslated regions (5' and 3' UTRs, respectively). Sequence comparisons of the open reading frames of the α-subunit genes identified two point mutations (V419L and L925I) that were presented only in the NY-BB population. L925I, located the intracellular loop between IIS4 and IIS5, has been previously found in a highly pyrethroid-resistant populations of whitefly (Bemisia tabaci). V419L, located in the IS6 transmembrane segment, is a novel mutation. A Val to Met mutation at the corresponding position of the bed bug V419, however, has been identified in the tobacco budworm as a kdr-type mutation. This evidence suggests that the two mutations are likely the major resistance-causing mutations in the deltamethrin-resistant NY-BB through a knockdown-type nerve insensitivity mechanism.