RESUMO
The whitefly, Bemisia tabaci (Gennadius), is a cryptic species complex that attacks >600 different species of plants and transmits several plant viruses causing severe economic losses. Until 2010, the B. tabaci complex comprised 24 distinct putative species. Recently, at least 15 new species have been reported. The objective of this study was to identify B. tabaci species present in bean, melon, and tomato crops in Argentina by applying phylogenetic analyses and pairwise comparison of genetic distances of mitochondrial cytochrome c oxidase subunit I (mtCOI) sequences. The 39 proposed whitefly species were identified with both analyses, and the presence in Argentina of one indigenous species, New World 2 (NW2), and two introduced species, Middle East-Asia Minor one (MEAM1) and Mediterranean, was confirmed. Common bean crop presented the three whitefly species detected, with NW2, MEAM1, and Mediterranean being present all together under field conditions. Also, Mediterranean was the only species identified in tomato, whereas MEAM1 was found in melon. To the best of our knowledge, Mediterranean is a recent invasive species in open-field agriculture in the American continent and in greenhouse tomato in Argentina. Additionally, we provide the first report of MEAM1 in common bean and melon. These findings raise several questions on the future scenario of B. tabaci and the viruses it transmits in Argentina.
Assuntos
Produtos Agrícolas , Hemípteros/classificação , Simpatria , Animais , Argentina , Hemípteros/genéticaRESUMO
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).
Assuntos
Begomovirus/genética , Genoma Viral/genética , Doenças das Plantas/virologia , Vírus Reordenados/genética , Solanum lycopersicum/virologia , Argentina , Sequência de Bases , Begomovirus/patogenicidade , Produtos Agrícolas/virologia , DNA Viral/genética , Vírus do Mosaico/genética , Filogenia , Recombinação Genética , Análise de Sequência de DNARESUMO
Begomovirus infection is becoming a threat in fresh-market tomato in Argentina, where mixed infections with begomoviruses are common. The complete sequence of a begomovirus isolate infecting tomato sampled in Salta was molecularly characterized. Phylogenetic analysis showed that this virus isolate is closely related to previously reported Brazilian, Bolivian and Argentinean begomoviruses. The associated symptoms in Nicotiana benthamiana and Solanum lycopersicum were determined by biolistic delivery of infectious DNA-A and DNA-B clones. This begomovirus isolate induced leaf mottling, rugosity and dwarfing, and growth retardation in tomato. Based on these symptoms, we propose the name of tomato dwarf leaf virus (ToDLV) for this new begomovirus.
