Grape berry native yeast microbiota: advancing trends in the development of sustainable vineyard pathogen biocontrol strategies

Grape berry is an ecological niche for a myriad of microbes, whose interactions with one another modulate fruit health and can play a role in fermentation, imparting character and distinctiveness to wines. With the growing concerns about and awareness of the risks associated with the overuse of chemical pesticides in viticulture, microbial-based pest control is increasingly encouraged as a more sustainable and environmentally friendly strategy. The use of yeasts from grape berries is a promising alternative for the control of vineyard diseases and their increasing acceptance is rapidly changing our perception of fungicides. In this paper, we provide an overview of the latest methodologies for characterising the dynamics of grape berry yeasts in the context of grape disease management, and discuss the prospects for their effective use as biocontrol agents in viticulture. Most research has focused on the control of fruit rots produced by Botrytis, Aspergillus, Colletotrichum and Penicillium spp. using formulations that comprise single strains of specific yeast genera, including Aureobasidium, Metschnikowia, Saccharomyces, Pichia, Candida and Rhodotorula. However, the challenging disparity between successful biocontrol outcomes obtained in vitro and their low applicability in the field is a major limitation for the large-scale implementation of these strategies. Novel research approaches for maximising the stability and efficiency of yeast-derived bioactives are discussed in this review.