Year, Location, and Variety Impact on Grape-, Soil-, and Leaf-Associated Fungal Microbiota of Arkansas-Grown Table Grapes

With the recent advancement of next-generation sequencing methods, there has been an increase in studies on identification of vineyard microbiota, winery-associated microbiota, and microbiota in wine fermentation. However, there have been few studies investigating the fungal microbiota of table grapes which present distinct spoilage and food safety challenges. The aims of this study were to identify and compare the impact of year, variety, and vineyard location on grape, leaf, and soil fungal communities of two varieties of table grapes, Faith and Gratitude, grown in two open-air vineyards and one high tunnel vineyard. The grape, leaf, and soil mycobiota were analyzed using high throughput amplicon sequencing of the ITS region. The sampling year and location of table grapes had an impact on grape, leaf, and soil mycobiota. Fungal diversity of grape, leaf, and soil was greater in 2017 than in 2016. Grape and leaf samples presented strong similarities in fungal communities with abundance of Sporidiobolaceae and Filobasidium in two vineyards and Cladosporium in another one. The high tunnel structure had distinct grape and leaf fungal communities compared to the two other vineyard locations. Mortierella was the predominant genus (27%) in soil samples for the three locations; however, genera of lower abundance varied between locations. These results provide extensive description of fungal communities in less-studied table grape vineyards and high tunnels, providing useful insight of potential threats and preventive strategies to help improve the production and marketability of table grapes.