doi:10.1038/nindia.2010.171 Published online 30 November 2010
Plant biologists have described the genetic diversity of two regional isolates of the tomato leaf curl virus (ToLCV) from the north and south of India. The data will help address the need to tackle the high genomic diversity of the virus, which poses a major threat to tomato production in Asia.
Around the world, ToLCV — members of the genus Begomovirus — affect crops such as cassava, cotton, grain legumes and vegetables. ToLCV isolates from Northern India have been shown to possess bipartite genome (designated as DNA A and DNA B), whereas those from Australia, Taiwan and Southern India have a single genomic component (DNA A).
The researchers studied two isolates of monopartite ToLCV by infecting tomatoes in two extreme regions (north and south) of India. They report the complete DNA sequence of the two isolates identified as ToLCV-CTM and ToLCVK3/K5. These novel isolates had the characteristic features of Begomovirus genome organization and were found to be monopartite.
Sequence analyses and phylogenetic studies indicated that these isolates might have evolved by recombining viruses related to two or more viral ancestors. The researchers say the existence of different ToLCV isolates having high genome diversity poses a threat to tomato production in Asia. The identification of these isolates will help to tackle this potential problem.