Identification of a mutation in the para-sodium channel gene of the cattle tick Rhipicephalus microplus associated with resistance to flumethrin but not to cypermethrin

Jonsson, N.N. , Cutullè, C., Corley, S.W. and Seddon, J.M. (2010) Identification of a mutation in the para-sodium channel gene of the cattle tick Rhipicephalus microplus associated with resistance to flumethrin but not to cypermethrin. International Journal for Parasitology, 40(14), pp. 1659-1664. (doi:10.1016/j.ijpara.2010.07.006)

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Abstract

A mutation in the domain II S4–5 linker region of the para-sodium channel gene has been associated previously with synthetic pyrethroid (SP) resistance in the cattle tick (Rhipicephalus microplus) in Australia. This is a C → A mutation at nucleotide position 190, which results in a leucine to isoleucine amino acid substitution (L64I). In a survey of 15 cattle tick populations with known SP resistance status, sourced from Queensland and New South Wales in Australia, there was a strong relationship (r = 0.98) between the proportion of ticks carrying the L64I homozygous resistant genotype and the survival percentage after exposure to a discriminating concentration of cypermethrin in the bioassay, as expected. However, among populations resistant only to flumethrin, the L64I homozygous genotype was not found. The sequence obtained for a 167 bp region including domain II S4–5 linker in flumethrin-resistant ticks identified a G → T non-synonymous mutation at nucleotide position 214 that results in a glycine to valine substitution (G72V). The frequency of the G72V homozygous genotype in each population was found to be moderately related to the survival percentage at the discriminating concentration of flumethrin in the larval packet test (r = 0.74). However, a much stronger relationship between genotype and resistance to flumethrin was observed when the heterozygotes of L64I and G72V were added to the G72V homozygotes (r = 0.93). These results suggest that there is an interaction between the two mutations in the same gene, such that flumethrin resistance might be conferred by either two copies of the G72V mutation or by being a L64I and G72V heterozygote.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Jonsson, Professor Nicholas
Authors: Jonsson, N.N., Cutullè, C., Corley, S.W., and Seddon, J.M.
Subjects:Q Science > QR Microbiology
College/School:College of Medical Veterinary and Life Sciences > School of Veterinary Medicine
Journal Name:International Journal for Parasitology
ISSN:0020-7519
Published Online:12 August 2010

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