Maize fine streak virus, a New Leafhopper-Transmitted Rhabdovirus.

ABSTRACT A previously uncharacterized virus was isolated from fall-planted sweet corn (Zea mays L., Syngenta GSS 0966) leaves showing fine chlorotic streaks. Symptomatic plants were negative in enzyme-linked immunosorbent assay against many maize viruses, but reacted weakly with antisera to Sorghum stunt mosaic virus suggesting a distant relationship between the viruses. The virus was readily transmitted by vascular puncture inoculation (VPI), but not by leaf-rub inoculation. Symptoms on maize included dwarfing and fine chlorotic streaks along intermediate and small veins that developed 12 to 17 days post-VPI. The isolated virus was bacilliform (231 +/- 5 nm long and 71 +/- 2 nm wide), with a knobby surface, and obvious helical structure typical of rhabdovirus morphology. Nucleorhabdovirus virions were observed by transmission electron microscopy of infected maize leaf tissue sections. Proteins unique to infected plants were observed in extracts of infected leaves, and the isolated virion contained three proteins with molecular masses 82 +/- 2, 50 +/- 3, and 32 +/- 2 kDa. Preliminary sequence analysis indicated the virus had similarity to members of the family Rhabdoviridae. The virus was transmitted by Graminella nigrifrons under persistent conditions. The data indicate the virus, provisionally designated Maize fine streak virus, is a new species in the genus Nucleorhabdovirus.

Transmission of Sorghum Stunt Mosaic Rhabdovirus by the Leafhopper Vector, Graminella sonora (Homoptera: Cicadellidae).

The transmission parameters of sorghum stunt mosaic rhabdovirus (SSMV) by the leafhopper Graminella sonora were determined. The minimum acquisition and inoculation times were 6 and 1 h, respectively, while 100% transmission was obtained from a 48-h acquisition access or a 24-h inoculation access period. Transmission efficiency was highest at temperatures of 24 to 36°C. The minimum latent period prior to transmission was 9 days at 30°C, with an 11-day incubation period necessary for 100% transmission. After a 14-day incubation period at 16°C, no transmission was obtained; however, doubling the incubation period to 28 days gave high levels of transmission. Double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) of individual leafhoppers held at 16°C for a 14-day incubation period detected no virus in leafhoppers, whereas over 50% of the leafhoppers had detectable virus after a 28-day incubation period. Graminella nigrifrons and Peregrinus maidis were not able to transmit SSMV.