Molecular genetic analysis of the spread of resistance to organophosphate insecticides and pyrethroids in populations of the Colorado potato beetle in the Republic of Bashkortostan

Background. We analyzed the spread of mutations in the gene ache - acetylcholinesterase responsible for resistance to the organophosphate insecticides, and in the gene ldvssc1 - electron-sensitive sodium channel, providing kdr-like resistance to pyrethroids in different regions of Republic of Bashkortostan. Materials and methods. Each group included 30-50 overwintered beetles. DNA from beetles was isolated by phenol-chloroform method. Amplification and analysis of genes ache and ldvssc1 were held by bi-PASA (bi-directional PCR amplification of specific allele) according to (Clark et al., 2001). Evaluation of susceptibility to the set of insecticides from classes of POI (aktellik), pyrethroids (decis) was carried out by topical infliction of ethanol solutions of insecticides (1 ml per individual) on the thorax of adults. Diagnostic concentrations of insecticides corresponding with this manner of treatment were determined in the preliminary experiments. Results. In the localities included in the group of southern and eastern regions, frequency distributions coincided. North-western and central group showed excess of phenotypes resistant to organophosphate insecticides compared with a share of genotypes carrying the mutant allele achе, and reducing the incidence of phenotypes resistant to pyrethroids, compared with the frequency of genotypes carrying the mutant allele ldvssc1. Conclusion. The interpretation of these results implies a significant contribution of some unknown component causing the increased level of non-specific resistance to organophosphate insecticides that can be associated with metabolic stability and also with structure and density of the beetle integuments. It should be noted that individuals carrying the mutant allele, providing resistance to pyrethroids, apparently did not have high adaptability, which may be the reason for this discrepancy in the frequencies of occurrence. Polymorphism and mutations in genes controlling metabolism (in particular, a family of genes of cytochrome P 450) should be studied to elucidate the genetic basis of Colorado potato beetle resistance in the territory of the Republic of Bashkortostan.

colorado potato beetle, resistance, mutations in genes ache, ldvssc1, organophosphate insecticides (POI), pyrethroids