A naturally occurring recombinant DNA-A of a typical bipartite begomovirus does not require the cognate DNA-B to infect Nicotiana benthamiana systemically

• Autor(a) principal: Galvao, Rafaelo M.
• Data de Publicação: 2003
• Outros Autores: Mariano, Andrea C., Luz, Dirce F., Alfenas, Poliane F., Andrade, Eduardo C., Zerbini, Francisco M., Almeida, Marcia R., Fontes, Elizabeth P. B.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://dx.doi.org/10.1099/vir.0.18783-0; http://www.locus.ufv.br/handle/123456789/18896
• topic: DNA-A; DNA-B; Nicotiana benthamiana

Species of the genus Begomovirus (family Geminiviridae) found in the western hemisphere typically have a bipartite genome that consists of two 26 kb DNA genomic components, DNA-A and DNA-B. We have identified and cloned genomic components of a new tomato-infecting begomovirus from Brazil, for which the name Tomato crinkle leaf yellows virus (TCrLYV) is proposed, and a DNA-A variant of Tomato chlorotic mottle virus (ToCMV-[MG-Bt1]). Sequence analysis revealed that TCrLYV was most closely related to ToCMV, although it was sufficiently divergent to be considered a distinct virus species. Furthermore, these closely related viruses induce distinguishable symptoms in tomato plants. With respect to ToCMV-[MG-Bt1] DNA-A, evidence is presented that suggests a recombinant origin. It possesses a hybrid genome on which the replication compatible module (AC1 and replication origin) was probably donated by ToCMV- [BA-Se1] and the remaining sequences appear to have originated from Tomato rugose mosaic virus (ToRMV). Despite the high degree of sequence conservation with its predecessors, ToCMV-[MG- Bt1] differs significantly in its biological properties. Although ToCMV-[MG-Bt1] DNA-A did not infect tomato plants, it systemically infected Nicotiana benthamiana, induced symptoms of mottling and accumulated viral DNA in the apical leaves in the absence of a cognate DNA-B. The modular rearrangement that resulted in ToCMV-[MG-Bt1] DNA-A may have provided this virus with a more aggressive nature. Our results further support the notion that interspecies recombination may play a significant role in geminivirus diversity and their emergence as agriculturally important pathogens.