Nucleotide sequence of tobamovirus Ob which can spread systemically in N gene tobacco.

The genomic RNA sequence of tobamovirus Ob (Ob), which can spread systemically in tobacco carrying the N gene, was determined. It consists of 6507 nucleotides and contains four open reading frames, exactly corresponding to the genomic organization of tobamoviruses known so far, i.e. encoding the 130K, 180K, 30K and coat proteins. There were no nucleotide overlaps between any open reading frames. The Ob nucleic acid sequence, predicted protein sequences and gene organization were compared with those of other tobamoviruses reported previously. This virus was originally reported as a tomato mosaic virus; however, the nucleotide sequence data given here refute this classification. The determinants that allow tobamovirus Ob to overcome the N gene, a feature peculiar to this virus, were not identified apart from sequence data. This virus should be regarded as a new tobamovirus. The determinants interacting with the tentative N gene product have not yet been analysed.