Unveiling the cultivable yeast endophyte diversity in muscadine grape berries and their known functional prospects

Muscadine grapes, which are valued for their fresh consumption, boutique wine production with distinctive flavors and aromas, and disease resistance, provide a unique ecological niche for investigating endophytic yeast communities. Despite their potential, the cultivable diversity and functional capabilities of these yeasts remain largely underexplored. In this study, we investigated culturable endophytic yeasts from the unskinned berries of diverse muscadine and bunch grape cultivars. Through molecular identification and morphological analysis, we identified 48 distinct yeast isolates spanning 18 species and 12 genera, with a predominance of non-Saccharomyces yeasts. Hanseniaspora guilliermondii emerged as the most abundant species, followed by members of the Pichia genus. Notably, novel species such as Nakaseomyces nivariensis and Wickerhamiella sorbophila were discovered, expanding the known diversity of grape-associated yeasts. Their documented roles in other grape systems highlight species-specific abilities to enhance wine quality, control pathogens, promote plant growth, and offer broader biotechnological applications. These findings not only deepen our understanding of yeast–grape interactions but also highlight diverse microbial reservoirs with promising applications in agriculture, food science, and biotechnology. This work lays the foundation for leveraging endophytic yeasts to increase crop quality, sustainability, and innovation across multiple domains. Diverse non-Saccharomyces yeast genera were isolated from grape cultivars. H. guilliermondii was the dominant species, followed by Pichia spp. Isolates exhibited varied colony and cellular morphologies. Novel grape-associated species, N. nivariensis and W. sorbophila, were identified. Literature underscores species-specific roles in wine fermentation and biocontrol.