Molecular characterization of a new whitefly-transmissible bipartite geminivirus infecting tomato in Panama

The nucleotide sequence of infectious clones of a tomato-infecting geminivirus from Panama [named tomato leaf curl virus (ToLCV-Pan) because of symptoms produced in infected tomato (plant stunting and mild leaf curling)] was determined. ToLCV-Pan has a bipartite genome (DNAs A and B) and computer analysis showed that the genome resembles that of other bipartite, whitefly-transmitted geminiviruses. DNA A (2584 nt) and B (2542 nt) have little sequence homology other than within the common region. ToLCV-Pan clones were introduced into Lycopersicon esculentum and infected plants developed the same symptoms as naturally infected tomatoes. Homology analysis of DNA A and B showed that ToLCV-Pan is most closely related to potato yellow mosaic virus (PYMV) from Venezuela. Pseudorecombination between ToLCV-Pan and PYMV did not give viable pseudorecombinant viruses. However, in some plants infected with the pseudorecombinant virus produced by ToLCV-Pan DNA A and PYMV DNA B, systemic movement of ToLCV-Pan DNA A was observed.