Genomic and Biological Characterization of Tomato necrotic streak virus, a Novel Subgroup 2 Ilarvirus Infecting Tomato in Florida.

Genomic and biological characterization of Tomato necrotic streak virus (TomNSV), a recently described ilarvirus infecting tomato in Florida, was completed. The full genome sequence revealed that TomNSV is a novel subgroup 2 ilarvirus that is distinct from other previously reported tomato-infecting ilarviruses: Tobacco streak virus, Parietaria mottle virus, and Tomato necrotic spot virus included in subgroup 1. In a host range experiment, TomNSV infected members of the Solanaceae and Chenopodiaceae plant families but did not infect sunflower (Helianthus annuus L.) or green bean (Phaseolus vulgaris L.). In tomato plants, the virus moved downward to the roots from the initial point of infection and then upward from the roots to tissues of active growth such as fruit, flowers, and young leaves where symptoms were produced. Thus, young leaves, fruit, and flowers are ideal for sampling for TomNSV. The transmission rate by seed collected from infected tomato plants was determined to be 0.33%. Collectively, the results of these experiments indicated that TomNSV is the causal agent of the necrotic streak disease of tomato observed in Florida since 2013.