Impact of Chemical and Biological Fungicides Applied to Grapevine on Grape Biofilm, Must, and Wine Microbial Diversity

Abstract

This study was aimed to measure the impact of the application of a bio-fungicide against Botrytis cinerea on the microbiota involved in the alcoholic fermentation (AF) of Tempranillo Rioja wines. For this purpose, a bio-fungicide composed of the biological control bacterium Bacillus subtilis QST713 was applied to the vineyard. The microbial diversity was analyzed from grape biofilm to wine. Impact on microbial diversity was measured employing indexes assessed with the software PAST 3.10 P.D. Results were compared to non-treated samples and to samples treated with a chemical fungicide mainly composed by fenhexamid. Overall, the impact of the biological-fungicide (bio-fungicide) on the microbial diversity assessed for grape biofilm and for musts was not remarkable. Neither of the tested fungicides enhanced the growth of any species or acted against the development of any microbial groups. The bio-fungicide had no significant impact on the wine microbiota whereas the chemical fungicide caused a reduction of microbial community richness and diversity. Although environmental threats might generate a detriment of the microbial species richness, in this study the tested bio-fungicide did not modify the structure of the microbial community. Indeed, some of the Bacillus applied at the grape surface, were detected at the end of the AF showing its resilience to the harsh environment of the winemaking; in contrast, its impact on wine quality during aging is yet unknown.

Unusual Non-Saccharomyces Yeasts Isolated from Unripened Grapes without Antifungal Treatments

“…On the other hand, the fact that this yeast only appears at the end of the ripening process may be due to the application of antifungal treatments during most parts of the period in which the samples were collected, except in the last week, during which there was no treatment applied. This hypothesis seems to fit with certain studies about antifungal treatments that produced a decrease in the yeast population [20,33,34]. Some of the microorganisms described in this work are not the common type of yeast founded on grape surface.…”

The Influence of Fungicide Treatments on Mycobiota of Grapes and Its Evolution During Fermentation Evaluated by Metagenomic and Culture-Dependent Methods

“…[1,13], and spoilage yeasts (such as Dekkera bruxellensis, Zygosaccharomyces bailii ) responsible for wine alterations [14,15]. Several studies reported that one of the most important factors that influences microbial community composition associated with grape berries are the vineyard agronomic practices [5,16,17,18,19,20,21,22,23]. Indeed, Cordero-Bueso and co-workers [20] showed a greater biodiversity of yeast species when the vineyard was treated with organic practices instead conventional ones.…”

“…On the contrary, Comitini and Ciani [5] found a reduction in the yeast diversity when organic fungicides were applied. More recently, Escribano-Viana et al [23] found that the bio-fungicide did not show significant impact on the wine microbiota whereas the chemical fungicide caused a reduction of microbial community richness and diversity.…”

Evaluation of Soil-Applied Chemical Fungicide and Biofungicide for Control of the Fusarium Wilt of Chrysanthemum and Their Effects on Rhizosphere Soil Microbiota

“…And soil enzyme activities have been reported to be greatly affected by soil microbial properties because transformations of the important organic elements occur through microorganisms [26]. It is reported that the biofungicide had no significant impact on the wine microbiota, whereas the chemical fungicide caused a reduction of microbial community richness and diversity [27].…”