Novos begomovírus associados a plantas daninhas no nordeste do Brasil

Abstract

The Begomovirus (family Geminiviridae) are characterized by infecting dicotyledonous plants, present twinned icosahedral particles with genomes composed of one or two components of circular single-stranded DNA (DNA-A and DNA-B). In addition to cultivated plants, the begomoviruses are also associated with a wide range of weeds. This study aimed to characterize the begomoviruses associated with weed families Malvaceae (Herissantia crispa, Waltheria indica, Sidastrum paniculatum, Sida rhombifolia e Triumfetta semitriloba), Solanaceae (Physalis sp.) and Lamiaceae (Hyptis sp.) In northeastern Brazil to assess their diversity and importance as sources of new virus to cultivated plants. Samples of weeds with symptoms typical of begomovirus infection were collected in the states of Alagoas, Pernambuco and Bahia during the years 2010-2012. We obtained a total of 28 genomic components (18 DNA-A and 10 DNA-B). Analysis of the sequences indicated the presence of eight species of begomovirus, six new species (HeYMV, TrYMV, PaYNV, PhYSV, HyRMV1 and HyRMV2). In phylogenetic analyzes between viruses obtained malvaceous weeds. indicate that all new species clustered with Brazilian begomoviruses. Evidence of recombination were detected manifold where the begomoviruses from Sida spp. and tomato were identified as parents. In weed Hyptis sp. and Physalis sp. Sequence analyzes indicated the presence of three new species of begomoviruses, the two found in the same sample Hyptis sp. (Mixed infection) and another found initially Physalis sp. and subsequently detected in Hyptis sp. In phylogenetic analyzes of these three new species formed a single monophyletic branch. The analyzes showed strong evidence of recombination between HyRMV1 and HyRMV2, and the like parental HyRMV1. The ToRMV was identified as a possible parental species HyRMV1 and PhYSV. Therefore, these results indicate that the weeds are important reservoirs of begomoviruses and that recombination events have apparently contributed to the emergence of new species in some hosts.