First Report of a Mastrevirus () Transmitted by the Corn Leafhopper.

Maize striate mosaic virus (MSMV; genus ) was recently reported in maize plants in Brazil and also detected by metagenomic analyses in the corn leafhopper, (DeLong & Wolcott). Although these findings suggested that is a potential vector, no transmission studies have been performed. Here, we tested the transmission of MSMV by from field-collected infected plants and plants infected with MSMV via leafhopper-mediated transmission in the laboratory; all plants were confirmed positive for MSMV by PCR. In each one of three transmission replicates, aviruliferous nymphs and adults were confined together on a source plant during a 4-day acquisition access period (AAP) and subsequently transferred to healthy maize seedlings (10 individuals per test plant) in a series of 4-day inoculation access periods (IAPs). We also tested transmission by the corn aphid, (Fitch) and by mechanical inoculation of healthy maize seedlings. Only transmitted MSMV, with overall transmission rates of 29.4 and 39.5% on field-collected infected plants and 18.5% on infected plants in laboratory. transmitted MSMV until the third (8 to 12 days after the AAP) or fourth successive IAP (12 to 16 days), with gradual loss in transmission efficiency and rate of viruliferous insects over time, suggesting a persistent but nonpropagative mode of transmission. Infected test plants showed mottling symptoms with mild chlorotic streaks and height reduction. This is the first report of transmission of a mastrevirus by , facilitating the completion of Koch's postulate for MSMV.