Nursery origin and propagation stage influence the endophytic fungal communities inhabiting grapevine planting stocks

In this study, we profiled GTD-pathogens in California nurseries, assessed how the propagation process impacted the incidence of trunk pathogens in planting material and identified infection routes. We surveyed four commercial nurseries across California and provided a culture-dependent and independent using GTAA metabarcoding for disease diagnosis. We focused on Vitis vinifera cultivars Cabernet-Sauvignon clone 8 and Chardonnay clone 4, which are two of the most widely planted varieties in California vineyards. Our evaluation covered various plant stages during the propagation process including cuttings from the mother vines, and grafted vines at the callusing stage, as well as green and dormant vines. Through this comprehensive sampling approach, we aimed to provide a detailed picture of the epidemiological landscape of these trunk pathogens and how each of these factors in the nursery influences their diversity, abundance, and incidence. This work will help nurseries make informed decisions to reduce GTD-pathogen load and improve the overall quality of plant nursery stocks.