Maize necrotic streak virus, a new maize virus with similarity to species of the family Tombusviridae

A new virus was isolated from maize (Zea mays L.) leaves showing mild mosaic symptoms and coinfected with Maize dwarf mosaic virus. The virus was readily transmitted by vascular puncture inoculation (VPI) but not leaf-rub inoculation. Virus symptoms on susceptible maize included pale green, yellow, or cream-colored spots and streaks measuring 1 to 2 mm on emerging leaves 5 to 7 days post-VPI. As leaves developed, the spots and streaks became spindle-shaped, then coalesced into long, chlorotic bands. These bands became translucent and necrotic around the edges. There was a distinctive chlorosis on the stalks that became necrotic. Based on these distinctive symptoms, the new virus was named Maize necrotic streak virus (MNeSV). The virus was not transmitted by Aphis maidis-radicus, Myzus persicae, Macrosiphum euphorbiae, Rhopalosiphum padi, Dalbulus maidis, Graminella nigrifrons, Perigrinus maidis, or Diabrotica virgifera virgifera under persistent or nonpersistent conditions. Both susceptible and resistant maize genotypes were identified following VPI with MNeSV. The isolated virus had isometric (32 nm) virions and a single 29.5-kDa coat protein. MNeSV was serologically distinct from morphologically similar maize viruses. The 4.3-kb single-stranded RNA genome had 25 to 53% sequence identity with species in the family Tombusviridae.