Wild Grape-Associated Yeasts as Promising Biocontrol Agents against Vitis vinifera Fungal Pathogens

Abstract

The increasing level of hazardous residues in the environment and food chains has led the European Union to restrict the use of chemical fungicides. Thus, exploiting new natural antagonistic microorganisms against fungal diseases could serve the agricultural production to reduce pre- and post-harvest losses, to boost safer practices for workers and to protect the consumers' health. The main aim of this work was to evaluate the antagonistic potential of epiphytic yeasts against Botrytis cinerea, Aspergillus carbonarius, and Penicillium expansum pathogen species. In particular, yeast isolation was carried out from grape berries of Vitis vinifera ssp sylvestris populations, of the Eurasian area, and V. vinifera ssp vinifera cultivars from three different farming systems (organic, biodynamic, and conventional). Strains able to inhibit or slow the growth of pathogens were selected by in vitro and in vivo experiments. The most effective antagonist yeast strains were subsequently assayed for their capability to colonize the grape berries. Finally, possible modes of action, such as nutrients and space competition, iron depletion, cell wall degrading enzymes, diffusible and volatile antimicrobial compounds, and biofilm formation, were investigated as well. Two hundred and thirty-one yeast strains belonging to 26 different species were isolated; 20 of them, ascribed to eight species, showed antagonistic action against all molds. Yeasts isolated from V. vinifera ssp sylvestris were more effective (up to 50%) against B. cinerea rather than those isolated from V. vinifera ssp vinifera. Six strains, all isolated from wild vines, belonging to four species (Meyerozyma guilliermondii, Hanseniaspora uvarum, Hanseniaspora clermontiae, and Pichia kluyveri) revealed one or more phenotypical characteristics associated to the analyzed modes of antagonistic action.

The ecology of insect–yeast relationships and its relevance to human industry

“…We are a species of yeast disperser that has inadvertently become too specialized [114]. There is a need, for example, for stresstolerant yeast species [92] able to use diverse substrates (such as pentoses, hexoses and lignocellulosic feedstocks [115]), modify food and beverage flavours [116,117], generate perfumes [93], and produce antibiotics, probiotics [118] and plant fungicides [119]. Insects present a source of diverse stress-tolerant yeasts [105,120] and those with specific traits for industrial applications (e.g.…”

Yeast Associated with Rice Phylloplane and Their Contribution to Control of Rice Sheath Blight Disease

“…Antagonistic yeasts use both direct and indirect mechanisms to inhibit plant pathogens, including production of volatile organic compounds, cell wall degrading enzymes, siderophores and biofilm as well as competition of nutrients, and phosphate and zinc oxide solubilization [18][19][20][21][22][23][24][25]. Volatile organic compounds (VOCs) are substances with a low molecular weight (lower than 300 Da), low polarity and high vapor pressure [26].…”

Yeast strains with antagonist activity against Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. and their phenotypic characterization

“…Production of extracellular glucanase and chitinase enzymes was regarded as having a major role in the antagonistic action, since these enzymes act as depolymerases on the pathogen cell wall, causing lysis and death (Tseng et al 2009). Also, emission of volatile compounds, such as acetic acid and hydrogen sulphide, and induction of several defence-related genes, have been reported as antagonistic mechanisms of this species (Cordero-Bueso et al 2017;Yan et al 2018b). Some other pathogens could be controlled, using Meyerozyma sp.…”