The Influence of Fungicide Treatments on Mycobiota of Grapes and Its Evolution during Fermentation Evaluated by Metagenomic and Culture-Dependent Methods (original) (raw)
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The relevance of non-Saccharomyces native yeasts for improving the complexity of wine aroma is increasingly recognised, besides their use in a range of biotechnological applications. Previously, we used a metagenomic approach to assess the effects of vineyard calcium sprays on the microbiota of grape berries cv. Vinhão and Loureiro. In this study, we aimed at assembling a catalogue of the cultivable yeasts from grape berries of these cultivars and to investigate the direct effect of calcium and other elicitors on the isolated taxa. Seventeen unique colony morphologies were identified, and the sequencing of the region spanning the rDNA internal transcribed spacers or the rDNA D1/D2 domain revealed that they are distributed into 13 different genera. Although the cultivar and vintage influenced the taxa abundance and diversity, Aureobasidium pullulans and Hanseniaspora uvarum were the most abundant species, ubiquitously populating the fruits together with Pichia terricola, Rhodotorula ...
Grape berry yeast communities: Influence of fungicide treatments
International Journal of Food Microbiology, 2013
The yeast communities colonising grape berry surfaces were evaluated for the influence of fungicide treatments in an organic vineyard (copper/sulphur-based products) and a conventional vineyard (commonly used fungicides). Analysis of yeast abundance and diversity was carried out on grape berries and juice during fermentation, using culture-dependent and -independent approaches. Yeast abundance was as generally reported for mature grapes and it was slight higher from grapes treated with conventional fungicides. Initial grape samples showed less yeast species diversity in the organic vineyard compared with the conventional one. In both vineyards, the dominant yeast were Candida zemplinina and Hanseniaspora uvarum (> 50%), respectively, typical species that colonise surfaces of mature grape berries. Metschnikowia pulcherrima was widely found in the conventional samples while it was only occasionally found in organic ones. Saccharomyces cerevisiae was isolated only at the end of natural fermentation (conducted in sterile condition), with lower levels in the organic samples. S. cerevisiae strains showed less intraspecies diversity in the organic samples (two genotypes), in comparison with the conventional samples (six genotypes).
Frontiers in Microbiology, 2015
The diversity of fungi in grape must and during wine fermentation was investigated in this study by culture-dependent and culture-independent techniques. Carignan and Grenache grapes were harvested from three vineyards in the Priorat region (Spain) in 2012, and nine samples were selected from the grape must after crushing and during wine fermentation. From culture-dependent techniques, 362 isolates were randomly selected and identified by 5.8S-ITS-RFLP and 26S-D1/D2 sequencing. Meanwhile, genomic DNA was extracted directly from the nine samples and analyzed by qPCR, DGGE and massive sequencing. The results indicated that grape must after crushing harbored a high species richness of fungi with Aspergillus tubingensis, Aureobasidium pullulans, or Starmerella bacillaris as the dominant species. As fermentation proceeded, the species richness decreased, and yeasts such as Hanseniaspora uvarum, Starmerella bacillaris and Saccharomyces cerevisiae successively occupied the must samples. The "terroir" characteristics of the fungus population are more related to the location of the vineyard than to grape variety. Sulfur dioxide treatment caused a low effect on yeast diversity by similarity analysis. Because of the existence of large population of fungi on grape berries, massive sequencing was more appropriate to understand the fungal community in grape must after crushing than the other techniques used in this study. Suitable target sequences and databases were necessary for accurate evaluation of the community and the identification of species by the 454 pyrosequencing of amplicons.
Influence of the farming system and vine variety on yeast communities associated with grape berries
International Journal of Food Microbiology, 2011
Wine production in most countries is based on the use of commercial strains leading to the colonisation of the wineries by these strains with the consequent reduction of autochthonous biodiversity. This implies that wine styles could therefore become standardised. The vineyard could be an important source of native yeasts of oenological interest. For this reason the objective of this study was to compare two agronomic conditions with the aim of preserving yeast biodiversity in the vineyard. A three year sampling plan was designed to evaluate the influence of different agronomic parameters on the biodiversity of fermentative grape yeasts. Thus two vineyards, one organic and one conventional, with three different grape varieties (Shiraz, Grenache and Barbera) were chosen. In total, 27 samples were collected from both vineyards. Of these, 1080 colonies were isolated and a total of 9 species were identified. The strains identified as Saccharomyces cerevisiae were genotyped by microsatellite analysis obtaining nine different electrophoretic patterns. Classical ecology indexes were used to obtain the richness (S), the biodiversity (H') and the dominance (D) of the species studied. The results indicated a clear influence on grape associated yeast diversity of the phytosanitary treatment used in the vineyard. This is the first time that classical ecology indexes have been used to study the ecology of the spontaneous fermentation of grape musts and the species Candida sorbosa and Pichia toletana have been described in vineyards of the Madrid winegrowing region.
The Impact of a Commercial Biostimulant on the Grape Mycobiota of Vitis vinifera cv. Barbera
Microorganisms
Reducing the use of fungicides, insecticides, and herbicides in order to limit environmental pollution and health risks for agricultural operators and consumers is one of the goals of European regulations. In fact, the European Commission developed a package of measures (the European Green Deal) to promote the sustainable use of natural resources and strengthen the resilience of European agri-food systems. As a consequence, new plant protection products, such as biostimulants, have been proposed as alternatives to agrochemicals. Their application in agroecosystems could potentially open new scenarios regarding the microbiota. In particular, the vineyard microbiota and the microbiota on the grape surface can be affected by biostimulants and lead to different wine features. The aim of this work was to assess the occurrence of a possible variation in the mycobiota due to the biostimulant application. Therefore, our attention has been focused on the yeast community of grape bunches from...
Analysis of non- Saccharomyces yeast populations isolated from grape musts from Sicily (Italy)
Journal of Applied Microbiology, 2008
Aims: The aim of this study was to identify the non-Saccharomyces yeast populations present in the grape must microflora from wineries from different areas around the island of Sicily. Methods and Results: Yeasts identification was conducted on 2575 colonies isolated from six musts, characterized using Wallerstein Laboratory (WL) nutrient agar, restriction analysis of the amplified 5AE8S-internal transcribed spacer region and restriction profiles of amplified 26S rDNA. In those colonies, we identified 11 different yeast species originating from wine musts from two different geographical areas of the island of Sicily. Conclusions: We isolated non-Saccharomyces yeasts and described the microflora in grape musts from different areas of Sicily. Moreover, we discovered two new colony morphologies for yeasts on WL agar never previously described.
Influence of fungicide treatments on the occurrence of yeast flora associated with wine grapes
Annals of Microbiology, 2008
in this work, the effects of fungicide treatments on the distribution and presence of the yeast flora that colonise the surfaces of grapes were investigated. Samples were collected from three vineyards treated with different fungicide applications using two methodologies to detect the yeast flora. our results show that organic fungicides applied on wine grapes during ripening cause a drastic reduction in the yeast flora. in the absence of fungicide treatments, Hanseniaspora uvarum was the dominant species, followed by Metschnikowia pulcherrima. Results of inorganic fungicide treatment trials confirmed the dominance of these wine fermenting yeasts together with a significant presence of Aureobasidium pullulans and Cryptococcus spp. the use of organic fungicides (in addition to inorganic fungicide application) showed A. pullulans as the predominant yeast species, followed by the Cryptococcus species, while wine fermenting yeasts were scarcely represented. the dominance of A. pullulans on grape surfaces treated with organic fungicides was confirmed in two consecutive vintages. in conclusion, organic fungicides directly applied on grape surfaces result in a dramatic reduction of yeast population and a shift in yeast populations towards A. pullulans.
The effect of fungicides on yeast communities associated with grape berries
FEMS Yeast Research, 2010
The influence of three commonly used fungicides (iprodione, pyrimethanil and fludioxonil plus cyprodinil) on the density and diversity of yeast populations present on grape berries was evaluated. At the time of harvest, the fungicide residues on grapes were below the maximum permitted levels. In general, larger yeast counts were found on the treated grapes than on the control samples. Among 23 species identified, Cryptococcus magnus, Rhodotorula glutinis and Sporidiobolus pararoseus dominated on sound grape berries. The results showed that the tested fungicides had only a minor impact on the composition of grape berry communities in comparison with the effect of weather conditions and the mode of grape berry sampling. Halo assays using filter discs loaded with fungicides were used as in vitro tests of the sensitivity of grape berry isolates. The fungicide containing pyrimethanil suppressed the growth of all basidiomycetous yeast species, while the sporadically occurring fermentative yeasts were unaffected. Fungicides with fludioxonil plus cyprodinil and iprodione as active substances showed specificity for certain species. Our results suggest that after the safety interval, the presence of fungicides has a minor impact on the composition of grape berry communities, although at the time of fungicide applications, the yeast species composition changes.
Australian Journal of Grape and Wine Research, 2012
Background and Aims: Grape mycobiota may be a determining factor for the population dynamics that develop during alcoholic fermentation for the production of wine. For sweet wine fermentations, high-sugar content grape musts are employed that represent complex microbial ecosystems. The focus of this study, the Passito di Caluso, is a sweet wine produced in the North of Italy from grapes harvested in the fall and subjected to a withering process. Methods and Results: The withering process was studied by sampling and microbiological analysis, while the alcoholic fermentation was followed by both culture-dependent and culture-independent approaches. During the withering process we observed a succession of three yeast populations associated with grapes. A high degree of species biodiversity was detected the last day of the monitoring period. The dominance of Saccharomyces cerevisiae in the inoculated fermentation was confirmed. Conclusions: A succession of yeast populations was observed during grape withering; species such as Candida zemplinina, Metschnikowia fructicola and Hanseniaspora uvarum were also detected during alcoholic fermentation. Autochthonous C. zemplinina populations could play an important technological role in sweet wine production. Significance of the Study: The grape mycobiota during withering was described and its fate during alcoholic fermentation determined by molecular identification methods.