Abstract
Synthetic transcripts of beet necrotic yellow vein virus (BNYVV) RNA-3 and RNA-4 were prepared from cloned cDNA in a bacteriophage T7 in vitro run-off transcription system. The RNA-3 transcripts tested had 5' non-viral extensions of 1, 23 or 64 nucleotides and identical 3' non-viral extensions of 12 nucleotides. An RNA-4 transcript with a 12 nucleotide 5' non-viral extension and a 28 nucleotide 3' non-viral extension was also synthesized. All of the transcripts were biologically active when coinoculated to Chenopodium quinoa with BNYVV isolates deficient in RNA-3 and/or RNA-4 but the presence of a long 5' non-viral sequence on the RNA-3 transcripts was found to diminish their specific activities considerably.