Transmission, characterization, and serology of a luteovirus associated with yellow leaf syndrome of sugarcane

A previously uncharacterized luteovirus was associated with one form of yel low leaf syndrome (YLS), a widespread disease of sugarcane (Saccharum sp.). The virus was named Sugarcane yellow leaf luteovirus (ScYLV), and was iden tified in major sugarcane-producing areas of the world. Typical disease sym ptoms were reproduced when ScYLV was transmitted by Melanaphis sacchari or Rhopalosiphum maidis from infected to healthy sugarcane, suggesting that th is virus may be the causal agent of one form of ns. The only known hosts of ScYLV are Saccharum and Erianthus spp. Virions of ScYLV were 24 to 29 nn i n diameter in sodium phosphotungstate at pH 5.0, had a buoyant density of 1 .30 g/cm(3) in Cs2SO4, and contained a 5.8-kb genomic ssRNA. The capsid pro tein had an estimated relative molecular mass of 27 kDa and was not glycosy lated. A polyclonal rabbit antiserum raised against ScYLV did not detect an y of eight other luteoviruses by enzyme-linked immunosorbent assay or immun osorbent electron microscopy, but in immunoblot assays, antibodies to ScYLV detected the RPV serotype of Barley yellow dwarf luteovirus. It is conclud ed that ScYLV is a previously undescribed luteovirus that is biologically a nd serologically distinct from other members of the group and may be the ca usal agent of one form of YLS of sugarcane.