Genetic diversity and population structure of tomato brown rugose fruit virus (ToBRFV) variants from Antalya province, Turkey

Abstract

In this study, bioinformatic analyses were carried out according to the fully coded CP and MP gene regions of the agent, using six novel tomato brown rugose fruit virus (ToBRFV) variants obtained from the production greenhouses in Antalya, where the infection was first detected in Turkey and global variants. Molecular evolutionary analyses using both CP and MP gene regions showed that all variants were distributed in three major clades. Population dynamics studies for both gene regions have shown that there was very low nucleotide diversity and haplotype diversity. The low haplotype diversity for the CP and MP genes indicated almost no recombination status. A strong negative selection was determined for CP and MP gene regions, dN/dS= 0.0877 and dN/dS=0.2104, respectively. Neutrality test results revealed that ToBRFV populations are in an expansion phase. Pairwise comparisons were performed between populations separated in the geographic hierarchy as American, European, and Asian variants, and the findings showed intense gene flow and high genetic similarity (FST<0,33 and migration rate >1). The results of this study reveal the recent population structure of the virus and suggest that necessary precautions should be taken in the international seed trade against contaminated seeds.