Artificial defective interfering RNAs derived from RNA 2 of beet necrotic yellow vein virus.

Long internal deletions were introduced into cloned cDNA of beet necrotic yellow vein virus RNAs 1-4 and transcripts containing the deletions were tested for their ability to inhibit replication of viral RNA in Chenopodium quinoa protoplasts and plants. No inhibition was observed with the deletion mutants based on RNAs 1, 3 and 4 but the RNA 2 deletion mutants all provoked a dramatic inhibition of synthesis of viral RNAs 1 and 2.