First report of tobacco streak virus infecting sunflower in Argentina.
During the 2018 to 2019 crop season, sunflower plants showing symptoms similar to those reported for the tobacco streak virus (TSV) were observed in one field of Rivera, Buenos Aires province, Argentina. The symptoms included leaf mosaic and severe necrosis of stem, petioles, leaves, and pith, often progressing to complete collapse and death of affected plants. Samples from symptomatic leaf tissue were collected from five plants, and leaves of sunflower seedlings maintained under greenhouse conditions were used as the healthy control. Based on the results of double antibody sandwich ELISA test, reverse transcription polymerase chain reaction and sequence analysis, the causal agent was confirmed as TSV. This virus has been associated with disease epidemics in sunflower and a range of legume and vegetable crops worldwide. This is thought to be the first report of the occurrence of TSV infecting sunflower crops in Argentina.