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-proteina se (HC-Pro) coding region of aphid transmissible (isolate 1) and non-t ransmissible (isolate 31) isolates of turnip mosaic virus (TuMV). HC-P ro 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 region s of two isolates of TuMV genomes encoded 458 amino acids of M(r) 51,7 46 (isolate 1) and M(r) 51,764 (isolate 31). The deduced amino acid se quence homology between these isolates was 98.7% with six different am ino acids. These amino acids appeared to regulate the activity of HC-P ro needed for aphid transmissibility of TuMV.