Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/16/2002
Publication Date: N/A
Technical Abstract: Viruses in the Luteoviridae family have single-stranded, positive-sense genomes that contain five or six open reading frames. They have been divided into three genera (Enamovirus, Luteovirus, and Polerovirus) based on genome organization, sequence similarity, and methods of gene expression. Recent taxonomic changes in the family include classification of the non-beet-infecting strains of Beet western yellows virus as a separate polerovirus named Turnip yellows virus; separation of strains of two species into distinct viruses (Cereal yellow dwarf-RPV-NY and Cereal yellow dwarf-RPS; Barley yellow dwarf virus-PAV and Barley yellow dwarf-PAS); and addition of Beet chlorosis virus to the Poleroviruses and Strawberry mild yellow edge associated virus and Sugarcane yellow leaf virus as unassigned species. Intra- and interfamily comparisons of the nucleotide and predicted amino acid sequences of members of the Luteoviridae suggest that RNA recombination has played an important role in the creation of new species in this family. For example, analysis of the complete genome sequence of Bean leafroll virus (BLRV) revealed a nucleotide sequence most similar to Soybean dwarf virus (SbDV), an unassigned member of the Luteoviridae. The BLRV and SbDV structural proteins are most similar to those of the Poleroviruses. Their nonstructural proteins are most similar to those of the Luteoviruses. Current criteria for assigning these viruses to a genus in the Luteoviridae would place BLRV and SbDV in the Luteoviruses. These criteria are therefore not sufficient to delineate the genetic diversity that has arisen through recombination in this family and should be reconsidered.