Genetic layout and genetic structure of the greenhouse whitefly Trialeurodes vaporariorum from Serbia

Abstract

Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), a haplo-diploid sap feeding insect species, is a vector of many plant viruses and a serious polyphagous pest of greenhouse-grown vegetables and ornamental plants worldwide. To explore the populations of this pest and recognize potential invasion routes, the genetic diversity and genetic structure of T. vaporariorum from Serbia were analysed using six microsatellite loci. PCR multiplex conditions were optimized and tested using 88 T. vaporariorum females collected from natural populations in 10 sampling locations in Serbia: Apatin (AP), Beograd (BG), Kovin (KO), Negotin (NE), Pirot (PI), Smederevska Palanka (SP), Subotica (SU), Svilajnac (SV), Trbušan (TR) and Vranjska Banja (VB). Observed heterozygosity ranged from 0.105 to 0.796, deviations of the frequency of genotypes from the expected Hardy–Weinberg equilibrium were detected in all populations. The values of the Fst parameters ranged from 0.011 between populations of AP and SU, up to 0.286 among the SV and BG populations. The obtained results for Fst values were used to explore genetic structure using several analyzes: PAST, Principal Coordinate Analysis – PCoA and SAMOVA. The analyzed T. vaporariorum populations were grouped in three distinct genetic clusters based on these population-genetic analyses: (1) BG, (2) AP, KO, SP, TR, VB and SU, and (3) SV, NE and PI. Also, BOTTLENECK identified reductions in effective size of SP population in the recent past and the significant heterozygosity deficiency was detected in the four populations VB, SU, BG and NE. These results demonstrate that populations of T. vaporariorum in Serbia show significant genetic differentiation, indicating the likelihood of multiple introductions of this important pest into Serbia, as well as the influence of crop protection and pest management on their genetic variability.