Characterization of the large (L) RNA of peanut bud necrosis tospovirus

The nucleocapsids purified from peanut plants systemically infected with pe anut bud necrosis virus (PBNV), a member of the genus Tospovirus, contained both viral(v) and viral complementary(vc) sense L RNAs. Defective forms of L RNA containing 'core polymerase region' were observed. The full length L RNA of PBNV was sequenced using overlapping cDNA clones. The 8911 nucleoti de L RNA contains a single open reading frame (ORF) in the vc strand, and e ncodes a protein of 330 kDa. At the 5' and 3' termini of the v sense RNA th ere were 247 and 32 nt untranslated regions, respectively, containing an 18 nt complementary sequence with one mismatch. Comparisons of the predicted amino acid sequence of the L protein of PBNV with other members of Bunyavir idae suggest that the L protein of PBNV is a viral polymerase. The L protei n had highest identity in the 'core-polymerase domain' with the correspondi ng regions of other tospoviruses, tomato spotted wilt virus and impatiens n ecrotic spot virus.