Tomato cultivation in Brazil is threatened by a number of tomato-infecting viruses belonging to the genus Begomovirus of the family Geminiviridae. Here, we report the full DNA-A sequences of three Brazilian begomoviruses: a potentially new tomato-infecting viruses, tomato interveinal chlorosis virus (ToICV), and two previously proposed begomoviruses for which only partial DNA-A sequences are available in the databases: tomato mottle leaf curl virus (TMoLCV) and tomato golden vein virus (TGVV). The complete sequences of the DNA-B components of TMoLCV and TGVV and the DNA-A components of a number of tomato severe rugose virus variants are also presented. Collectively, all of the analyzed sequences were phylogenetically clustered within the two major groups of Brazilian tomato-infecting begomoviruses.

BackgroundMonopartite begomoviruses (genus Begomovirus, family Geminiviridae) that infect sweet potato (Ipomoea batatas) around the world are known as sweepoviruses. Because sweet potato plants are vegetatively propagated, the accumulation of viruses can become a major constraint for root production. Mixed infections of sweepovirus species and strains can lead to recombination, which may contribute to the generation of new recombinant sweepoviruses.ResultsThis study reports the full genome sequence of 34 sweepoviruses sampled from a sweet potato germplasm bank and commercial fields in Brazil. These sequences were compared with others from public nucleotide sequence databases to provide a comprehensive overview of the genetic diversity and patterns of genetic exchange in sweepoviruses isolated from Brazil, as well as to review the classification and nomenclature of sweepoviruses in accordance with the current guidelines proposed by the Geminiviridae Study Group of the International Committee on Taxonomy of Viruses (ICTV). Co-infections and extensive recombination events were identified in Brazilian sweepoviruses. Analysis of the recombination breakpoints detected within the sweepovirus dataset revealed that most recombination events occurred in the intergenic region (IR) and in the middle of the C1 open reading frame (ORF).ConclusionsThe genetic diversity of sweepoviruses was considerably greater than previously described in Brazil. Moreover, recombination analysis revealed that a genomic exchange is responsible for the emergence of sweepovirus species and strains and provided valuable new information for understanding the diversity and evolution of sweepoviruses.

RESUMO: Introdução: A disseminação da infecção pelo vírus linfotrópico-T humano (HTLV) em famílias da área metropolitana de Belém, Pará, Brasil, e a ausência de estudos na população em geral requisitam investigações que esclareçam melhor a sua prevalência na região. Metodologia: Foi realizada pesquisa de anticorpos anti-HTLV-1/HTLV-2 em indivíduos adultos transeuntes de logradouros públicos de Belém, entre novembro de 2014 e novembro de 2015. A infecção foi confirmada por pesquisa de DNA proviral e foi realizada avaliação clínica e investigação intrafamiliar dos infectados. Resultados: Dos 1.059 indivíduos investigados, 21 (2,0%) apresentaram amostras sororeagentes, 15 (1,4%) confirmados para HTLV-1, 5 (0,5%) para HTLV-2 e o DNA proviral foi indetectável em 1 caso. A média de idade dos infectados (57,2) foi maior que a dos não infectados (46,2) (p = 0,0010). A infecção aumentou com a idade e se destacou nos indivíduos com renda familiar menor ou igual a um salário mínimo. A transmissão intrafamiliar parece ter ocorrido em todas as famílias investigadas. Dentre os portadores de HTLV-1, 30% (3/10) já apresentavam algum sintoma relacionado à infecção. Discussão: O aumento da infecção de acordo com a idade pode ocorrer por soroconversão tardia de infecção pré-adquirida ou pelo risco cumulativo de novas infecções, sobretudo em mulheres. Conclusão: A infecção por HTLV demonstrou moderada prevalência na população estudada, com predomínio do HTLV-1. Essa mostrou-se associada à baixa renda e ao aumento da idade das mulheres. Também apresentou disseminação intrafamiliar e negligência no diagnóstico das doenças associadas.

The complete genome sequences of two monopartite begomovirus isolates (genus Begomovirus, family Geminiviridae) present in a single sweet potato (Ipomoea batatas) plant collected in São Paulo, Brazil, are presented. Based on the current taxonomic criteria for the genus Begomovirus, one of the isolates was shown to represent a novel species, tentatively named Sweet potato leaf curl Sao Paulo virus (SPLCSPV). The other isolate represented a new strain of sweet potato leaf curl virus, named sweet potato leaf curl virus-Sao Paulo (SPLCV-SP). The full genome sequence of the SPLCSPV isolate shared the highest nucleotide identity (87.6%) with isolates of sweet potato leaf curl Spain virus (SPLCESV). Phylogenetic and recombination analyses were used to investigate the relationships of these isolates to other monopartite Ipomoea-infecting begomoviruses.