Molecular and biological properties of tomato necrotic stunt virus and development of a sensitive real-time RT-PCR assay.

The newly identified tomato necrotic stunt virus (ToNStV), with a genome of 10,057 nucleotides, had 60 % nucleotide sequence and 70 % coat protein amino acid sequence identity to other potyviruses. Analysis of a second ToNStV isolate revealed two single nucleotide substitutions. ToNStV induced stunting and chlorotic to necrotic leaf symptoms on tomato plants. In host-range assays, ToNStV systemically infected many species in the family Solanaceae and locally infected some species in the families Amaranthaceae, Brassicaceae and Cucurbitaceae. A sensitive and reliable real-time RT-PCR assay was developed using simply prepared crude tissue extract.