Identification of mutations in para-type sodium channel gene and acetylcholinesterase gene of different cotton whitefly, Bemisia tabaci (Genn.), (Hemiptera: Aleyrodidae), populations from Antalya

Cotton whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of most damaging insect pest on numerous cultivated crops worldwide. Furthermore, it has the ability to develop resistance to diverse group of insecticides rapidly, hence controlling the pest is problematic. The aims of current study are to investigate resistance status of different populations collected from Antalya, Turkey for four different insecticides and to detect pyrethroid and organophosphate resistance-associated mutations in kdr and ace loci, respectively.A set of insect populations collected from 6 different counties of Antalya (7 different locations), and a susceptible lab population (Koçarlı) collected earlier and maintained since 11.08.2009 at the Entomology lab of Akdeniz University were used as insect materials. Leaf dip bioassay was employed for resistance screening and molecular diagnostic tools (DNA isolation, agarose gel electrophoresis, sanger sequencing with capillary electrophoresis) were used to monitor the frequency of the resistance mutations in the populations.The results of bioassays were shown that resistance ratios ranged from 2.2 to 164.5 for cypermetrin, 0.3 to 2.9 for deltamethrin, 0.2 to 2.9 for chlorpyrifos-ethyl, and 0.3 to 48.6 for thiamethoxam. DNA sequencing results showed that all populations including susceptible population (Koçarlı) had the F331W mutation in ace locus which is associated with OP resistance and the L925I mutation in kdr locus, which is associated with pyrethroid resistance. On the other hand, T929V mutation wasn?t found in any population. Furthermore, the two mutations in kdr locus did not occur together in the same individual. Moreover, mtCOI sequencing results indicated that all populations were B biotype.Overal, the results indicated that the use of pyrethroid and organophosphate insecticides on whitefly may not be effective on the regions sampled. Furthermore, the pest has been exposed to thiamethoxam more frequently in recent years and the resistance level may have reached to uncontrollable levels in three years. The fact that mutations associated with resistances were fixed in all sample areas suggest that the insecticides for whitefly control should not target acetylcholinestarase and para-type sodium channel.