Sugarcane yellow leaf virus: A novel member of the Luteoviridae that probably arose by inter-species recombination

The 5895 nucleotide long single-stranded RNA genome of Sugarcane yellow leaf virus Florida isolate (SCYLV-F) includes six major ORFs. All but the first of these are homologous to genes of known function encoded by viruses of the three newly defined genera in the Luteoviridae ('luteovirids'), i.e. poleroviruses, luteoviruses and the enamoviruses. SCYLV-F ORFs 1 and 2 are most closely related to their polerovirus counterparts, whereas SCYLV-F ORFs 3 and 4 are most closely related to counterparts in luteovirus genomes, and SCYLV-F ORF5 is most closely related to the read-through protein gene of the only known enamovirus. These differences in affinity result from inter-species recombination. Two recombination sites in the genome of SCYLV-F map to the same genomic locations as previously described recombinations involving other luteovirids. A fourth type of luteovirid, Soybean dwarf virus, has already been described. Our analyses indicate that SCYLV-F represents a distinct fifth type.