Tomato mottle wrinkle virus, a recombinant begomovirus infecting tomato in Argentina.

Begomoviruses seriously threaten tomato production in South America. Here, we present the molecular characterization of a novel tomato-infecting begomovirus isolated in Argentina and demonstrate its infectivity. After cloning and sequencing the complete genome of this new virus, pairwise genetic distance and phylogenetic analyses revealed that it is a novel virus that is closely related to other begomoviruses found in Argentina, Brazil and Bolivia. We have proposed naming the virus tomato mottle wrinkle virus (ToMoWrV), based on symptoms produced upon its biolistic inoculation into tomato plants. Recombination analysis revealed that ToMoWrV is a recombinant, with parental sequences likely belonging to the South American begomoviruses soybean blistering mosaic virus (SoBlMV) and tomato yellow vein streak virus (ToYVSV).

Characterization of tomato yellow vein streak virus, a begomovirus from Brazil.

Tomato yellow vein streak virus (ToYVSV) is a tentative begomovirus (Family Geminiviridae) species that seriously affects tomato and potato production in Brazil. Here, we have determined the genomic and biological characteristics of a ToYVSV isolate (Ba3) from a potato plant sampled in Rio Grande do Sul State, Brazil. The DNA-A nucleotide sequence of Ba3 and another previously reported ToYVSV isolate share 89.7% sequence identity. These ToYVSV isolates should be classified as a new species in that they are most closely related to Soybean blistering mosaic virus with which they share only approximately 80% identity. Cloned constructs containing 1.5 mer copies of the ToYVSV genomic components were found, by biolistic bombardment, to be infectious in at least 11 plant species in 2 families (Solanaceae and Malvaceae). Symptoms on tomato and potato plants were identical to those originally observed on field-infected plants. ToYVSV was also sap-transmissible from Nicotiana benthamiana to N. benthamiana and tomato, but not to potato plants.

Comparative analysis of American Dengue virus type 1 full-genome sequences.

Dengue virus (DENV; Genus Flavivirus, Family Flaviviridae) has been circulating in Brazil since at least the mid-1980s and continues to be responsible for sporadic cases of Dengue fever and Dengue hemorrhagic fever throughout this country. Here, we describe the full genomes of two new Brazilian DENV-serotype 1 (DENV-1) variants and analyze these together with all other available American DENV-1 full-genome sequences. Besides confirming the existence of various country-specific DENV-1 founder effects that have produced a high degree of geographical structure in the American DENV-1 population, we also identify that one of the new viruses is one of only three detectable intra-American DENV-1 recombinants. Although such obvious evidence of genetic exchange among epidemiologically unlinked Latin American DENV-1 sequences is relatively rare, we find that at the population-scale there exists substantial evidence of pervasive recombination that most likely occurs between viruses that are so genetically similar that it is not possible to reliably distinguish and characterize individual recombination events.