Detection, Identification and Molecular Characterization of Tomato Mosaic Virus (ToMV) Isolates from Pakistan.

Tomato mosaic virus (ToMV) is one of the lethal tomato pathogens. In this study, we collected tomato leaves exhibiting interveinal chlorosis from farmer’s fields in district Lahore, Pakistan. The presence of tobamoviruses was confirmed through extracting RNA, cDNA synthesis, PCR amplification and subsequent sequencing of capsid protein (CP) gene of ToMV that contained 480 nucleotides (encoded for 160 amino acids making ~17 kDa protein) located at 5703rd to 6182nd nucleotide position in ToMV genome. In sequence analysis, Pakistani isolates shared 98.9-99.5% and 97.3-99.3% nucleotide and amino acid homologies with each other and 96-99% and 90-98.6% with other isolates respectively. In phylogenetic analysis the Pakistani isolates grouped with Iranian and Chines isolates, exhibiting higher nucleotides and amino acids identities as well. This research reveals a geographical association among Pakistani, Chines and Iranian ToMV isolates. The study suggests extensive surveys of tobamoviruses infecting field crops for their detailed genetic information.