Tropical Plant Pathology
Print version ISSN 1982-5676
GONZALEZ-AGUILERA, Jorge et al. Genetic structure of a Brazilian population of the begomovirus Tomato severe rugose virus (ToSRV). Trop. plant pathol. [online]. 2012, vol.37, n.5, pp.346-353. ISSN 1982-5676. http://dx.doi.org/10.1590/S1982-56762012000500007.
Begomoviruses are whitefly-transmitted single-stranded DNA viruses of great economic importance in the tropics and subtropics. Several begomovirus species have been reported in tomatoes in Brazil, but only a few predominate in the field, for unknown reasons. In this study begomovirus-infected tomato samples were collected in Viçosa, State of Minas Gerais, in Nov/2009 and Dec/2010. Viral genomes were amplified, cloned and sequenced. A total of 36 DNA-A components were obtained. Sequence comparisons indicated the presence of a single begomovirus, Tomato severe rugose virus (ToSRV), with pairwise identities between isolates ranging from 97.3 to 100%. Subdivision tests indicated the existence of a single population. The analysis of variability descriptors indicated that the ToSRV population has a genetic variability similar to other begomovirus populations described in Brazil infecting tomato. Neutrality tests suggested the occurrence of purifying selection acting upon the population. Recombination analysis identified recombination events with begomoviruses from the weed species Sida micrantha. The wide distribution of ToSRV in the field and the detection of recombination indicate that continuous monitoring of viral populations in the field will be required to enable an efficient resistance-based control strategy for begomoviruses.
Keywords : geminivirus; genetic variability; recombination.