| 17046602 |
Liu Z, Tan J, Huang ZY, Dong K: Effect of a fluvalinate-resistance-associated sodium channel mutation from varroa mites on cockroach sodium channel sensitivity to fluvalinate, a pyrethroid insecticide. Insect Biochem Mol Biol. 2006 Nov;36(11):885-9. Epub 2006 Sep 3.
Fluvalinate is a pyrethroid insecticide that is widely used in the control of the varroa mite (Varroa destructor), an ecto-parasite of the honeybee. Previously we identified four fluvalinate-resistance-associated mutations in the sodium channel gene of the varroa mite. One of the mutations caused a leucine (L) to proline (P) change at 1770 in the linker connecting domains III and IV of the sodium channel. Interestingly, at the position corresponding to the L to P mutation, all known insect (including honeybee) sodium channel proteins already naturally contain a P residue (e.g., P1577 in the cockroach sodium channel BgNa (v)). To determine whether insect sodium channels are less sensitive to fluvalinate than arachnid sodium channels, we replaced P1577 with an L in a BgNa (v) variant (BgNa (v) 1-1) and examined the sensitivity of the recombinant channel to fluvalinate. The P1577L substitution did not alter the gating properties of the BgNa (v) 1-1 channel expressed in Xenopus oocytes. However, the BgNa (v) 1-1 (P1577L) channel was five-fold more sensitive to fluvalinate compared with the BgNa (v) 1-1 channel. These results not only implicate the L to P mutation in fluvalinate resistance in varroa mites, but also suggest a possible contribution of L1770 to the higher sensitivity of varroa mites to fluvalinate than their insect hosts. |
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