A Survey for Nine Major Viruses of Grapevines in Tennessee Vineyards

Abstract

Despite the significance of grape production to the fruit industry in Tennessee (TN), no published information has been available on viruses affecting grapevines in the state. Hence, a survey was conducted during the 2016 and 2017 growing seasons to determine the status of nine major viruses of grapevines in TN vineyards by taking advantage of classical serological assays and confirmatory nucleic acid-based diagnostic approaches. A total of 349 samples from 23 grapevine cultivars mostly displaying viral-like symptoms were collected from 23 commercial vineyards. All samples were assayed by DAS-ELISA for arabis mosaic virus (ArMV), grapevine leafroll-associated virus (GLRaV)-1, GLRaV-2, GLRaV-3, GLRaV-4, grapevine fanleaf virus (GFLV), tobacco ringspot virus (TRSV), and tomato ringspot virus (ToRSV). Selected serologically positive samples were also tested by RT-PCR, followed by Sanger sequencing of the generated amplicons. Additionally, 19 grapevines displaying symptoms characteristic of grapevine red blotch virus (GRBV) were also assayed by PCR followed by confirmatory sequencing-based methods. Collectively, these assays verifiably detected GLRaV-1, GLRaV-2, GLRaV-3, ToRSV, and GRBV in TN vineyards. This is the first record of the presence of these viruses in TN vineyards. ArMV, GLRaV-4, GFLV, and TRSV were not detected. The majority of samples tested positive for a single virus, whereas mixed infections with more than one virus were detected in 37% of samples.