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Moroccan pepper virus (MPV) and Lettuce necrotic stunt virus (LNSV) have been steadily increasing in prevalence in central Asia and western North America, respectively, over the past decade. Recent sequence analysis of LNSV demonstrated a close relationship between the coat proteins of LNSV and MPV. To determine the full extent of the relationship between LNSV and MPV, the genomes of three MPV isolates were sequenced and compared with that of LNSV. Sequence analysis demonstrated that genomic nucleotide sequences as well as virus-encoded proteins of the three MPV isolates and LNSV shared 97% or greater identity. A full-length clone of a California LNSV isolate was developed and virus derived from infectious transcripts was used to evaluate host plant reactions under controlled conditions. Symptoms of LNSV matched those described previously for MPV on most of a select series of host plants, although some differences were observed. Collectively, these molecular and biological results demonstrate that LNSV should be classified as MPV within the family Tombusviridae, genus Tombusvirus, and confirm the presence of MPV in North America.

The complete nucleotide sequence of tomato infectious chlorosis virus (TICV) was determined and compared with those of other members of the genus Crinivirus. RNA 1 is 8,271 nucleotides long with three open reading frames and encodes proteins involved in replication. RNA 2 is 7,913 nucleotides long and encodes eight proteins common within the genus Crinivirus that are involved in genome protection, movement and other functions yet to be identified. Similarity between TICV and other criniviruses varies throughout the genome but TICV is related more closely to lettuce infectious yellows virus than to any other crinivirus, thus identifying a third group within the genus.