Caracterização dos padrões de recombinação em genomas de begomovírus brasileiros

Abstract

The genus Begomovirus (Family Geminiviridae) comprises a large number of viral species whose populations are characterized by the ability to evolve rapidly due to the mechanisms of mutation, recombination and pseudorecombination. Together, these mechanisms are responsible for the high degree of genetic variability observed in viral populations specially those associated with uncultivated hosts. Recombination refers to the exchange of DNA or RNA segments between genomes of distinct viruses. Studies indicate that recombinant begomoviruses are frequently found in Brazil, infecting several crops of economic importance. In this context, this study aimed to contrast the recombination patterns in the DNA-A sequences of begomoviruses obtained from plants collected in Brazil and in other countries from Americas. The sequences were obtained from Genbank and aligned for the detection of recombinant segments and inference of population-scaled recombination rates. Based on the analysis of the results, the genomes of Brazilian begomoviruses showed a higher number of recombination sites ("breakpoints") in the intergenic region (IR). In contrast, the genomes of begomoviruses from other American countries presented a larger number of recombination sites in the region corresponding to the ren gene (replication enhancer). To better characterize the recombination patterns in the viral genomes, recombination rates were inferred for populations of the Brazilian begomoviruses Tomato severe rugose virus (ToSRV) and Macroptilium yellow spot virus (MaYSV). The recombination rates inferred in this study for genomes of begomoviruses obtained from plants collected in Brazil were considerably different from that previously determined for another viral population.