Nucleotide sequences of the helper component-proteinase genes of aphid transmissible and non-transmissible isolates of turnip mosaic virus.

We have compared nucleotide sequences of the helper component-proteinase (HC-Pro) coding region of aphid transmissible (isolate 1) and non-transmissible (isolate 31) isolates of turnip mosaic virus (TuMV). HC-Pro coding regions of both TuMV isolates 1 and 31 were 1,374 nucleotide long. The nucleotide sequence homology between these isolates was 93.5%, with 89 nucleotides substitution. The nucleotides of HC-Pro regions of two isolates of TuMV genomes encoded 458 amino acids of M(r) 51,746 (isolate 1) and M(r) 51,764 (isolate 31). The deduced amino acid sequence homology between these isolates was 98.7% with six different amino acids. These amino acids appeared to regulate the activity of HC-Pro needed for aphid transmissibility of TuMV.