The work of Tristezza et al. reported new insights into the oenological potential of autochthonous Apulian strains of Hanseniaspora uvarum and S. Liu et al., 2015), which includes yeasts, lactic acid bacteria (LAB) and acetic acid bacteria (AAB).
MATERIALS AND METHODS Grape Withering and Sampling
The binding process was performed using the procedure of Albertsen et al. 2013), which is based on sequence composition independent binning and tetranucleotide binning. Shotgun reads were used to profile the composition of the microbial community using MetaPhlAn version 1.7.7 (Segata et al., 2012).
RESULTS
This approach revealed that the eukaryotic community consisted mainly of members of the phylum Ascomycota reads) and reads) of reads in the TW and AW samples, respectively (Figure 2). Conversely, the distribution of the genera of the Eurotiomycetes class (47% of the Ascomycota fraction for the TW berries; 15,436 reads), such as Aspergillus and Penicillium, varied between the two samples, representing the .
DISCUSSION
Under these conditions, the noble rot infection was reported to occur in a limited part of the grains (Tosi et al., 2012). Pinot gris, and was considered representative of the phyllosphere core bacterial community (Perazzolli et al., 2014).
AUTHOR CONTRIBUTIONS
Further studies should be carried out to determine whether the alteration of the microbial communities on grape surfaces wilting under different conditions can lead to significant chemical variations of Corvina berry metabolites, thereby influencing the final wine characteristics and sensory properties. In this way, WMS can open new perspectives in the knowledge and management of traditional processes, such as the wilting process of Corvina grapes, with an impact on the winemaking of important Italian wines.
ACKNOWLEDGMENTS
SUPPLEMENTARY MATERIAL
In fact, the natural diversity of these metabolic pathways and the contribution of different microorganisms involved in the fermentation process is well documented (Setati et al., 2012). However, little is still known about the dynamics of the microbial community during the fermentation process.
Introduction
Materials and Methods Sample Collection
The V1-V3 hypervariable region of the 16S rRNA gene was amplified from the environmental DNA using the primer set 28F/519R (28F: 5-ccatctcatccctgcgtgtctccgactcagxxxxxxxxGAG TTTGATCNTGGCTCAG-3 and 519R: 5-cctatcccctgtgtgccttg gcagtctcagGTNTTACNG CGGCKGCTG-3). Representative sequences were aligned using the PyNAST algorithm (Caporaso et al., 2010a) and the alignment was filtered to remove common gaps.
Results
Further analysis of the bacterial community resulted in the detection of 96 genera in all samples, of which 33 genera were found in both organically and conventionally fermented musts. Representatives of the genus Gluconobacter, an acetic acid bacterium commonly found associated with grape skins (Joyeux et al., 1984), were detected in the microbiome of both wine varieties, although discrete changes were observed within the Gluconobacter population between organic and conventionally fermented wines .
Discussion
Various parameters, such as sugar concentration, temperature, pH value, ethanol concentration and a variety of chemical characteristics, of the grape must were monitored during the fermentation process (Figure 3 and Table 4). To increase our understanding of microbial dynamics, particularly bacterial dynamics, during grape fermentation, we used culture-independent 16S rRNA amplicon sequencing to determine changes in the bacterial population of grape must during the fermentation process.
Author Contributions
The other possibility could be that the growth of Pseudomonas and some members of Comamonadaceae was suppressed by antimicrobial components associated with organically fermented wine by native yeasts. Further comprehensive study of how the bacterial species interacted with wine and how the microbial community dynamics correlated with grape must and wine components during the fermentation process would be of great value for the development of improved methods to control wine quality.
Supplementary Material
A less significant decrease was observed during organic fermentation [73% (day 2), 34% (day 10), 13% (day 13)], which may also be explained by the antimicrobial activity of a native yeast that could have been associated with the grapes. In this study, we obtained a more detailed understanding of the temporal order of the bacterial population and associated changes in wine chemistry during conventionally and organically fermented grapes using NGS technologies, which could not be studied with less sensitive molecular approaches (i.e. PCR-DGGE).
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY). Due to the existence of a large population of fungi on grape berries, massive sequencing was more suitable for understanding the fungal community in grape must after crushing than the other techniques used in this study.
INTRODUCTION
Wang C, García-Fernández D, Mas A and Esteve-Zarzoso B (2015) Fungal diversity in grape must and wine fermentation assessed by mass sequencing, quantitative PCR and DGGE. The diversity of fungi in grape must and during wine fermentation was investigated in this study by culture-dependent and culture-independent techniques.
MATERIALS AND METHODS Spontaneous Fermentations
Samples of grape must with molds found mostly on plates, resulting in difficult quantification or isolation, are labeled with "∗". qPCR results are shown as cell concentration (cells/ml), species detected by DGGE are represented by "+", and results from mass sequencing are shown as percentages. Due to the rich diversity of mass ranking results, only major species with percentages higher than 5% are shown in the table, and species with lower percentages in some samples, if ranked, are marked with "<." The symbol of “nd” represents species with lower concentrations below the detection limit (100 cells/ml) by qPCR and species undetectable by the other three techniques.
MATERIALS AND METHODS
Clade strains are usually present in the must during the early fermentation phase. Clear zones were produced when the antagonist caused total growth inhibition in the lawn of the susceptible isolate.
MATERIALS AND METHODS Yeast Sampling
The frequency (F') and the occurrence (I') of the yeast species in the grape samples were according to Tristezza et al. The prevalence of the yeast species observed in Georgian wine samples differs from that reported by Capece et al.
MATERIALS AND METHODS Grape Sampling and Spontaneous
S-ITS rRNA Region and Sequencing of the D1/D2 Region from 26S rRNA Gene
Recently, several non-Saccharomyces species have been associated with positive properties, such as the production of interesting aromatic compounds or the reduction of the final ethanol content of wine (Gonzalez et al., 2013; Jolly et al., 2014). This black yeast-like fungus is a common resident on the surface of healthy grapes, which would explain its presence at the beginning of the fermentation process (Fleet, 2003; Sun et al., 2014).
CONCLUSION
The only previous study carried out in Priorat (Torija et al., 2001) studied the yeast population dynamics of GA fermentation over a period of three years, and determined that the main non-Saccharomyces species isolated were C. Some authors who applied combined analysis in Saccharomyces already observed this fact (Fernández-Espinar et al., 2001; Schuller et al., 2004).
FUNDING
Thus, the description of this microbial diversity can be the first step in selecting a consortium of indigenous yeast microbiota that mimics spontaneous fermentation that could be used to produce wines with the Priorat imprint.
ACKNOWLEDGMENT
A total of 70 yeast cultures were isolated from countable WL agar plates: 52 in the middle of fermentation and 18 at the end. The potential winemaking role of the isolated yeast strains was assessed by evaluating oenological and behavioral traits in microfermentation trials on Aglianico cider.
MATERIALS AND METHODS Sampling and Yeast Isolation
The study and conservation of wine yeast biodiversity has recently become a matter of increasing interest (Di Maio et al., 2012). Similar results were obtained by Capece et al. cerevisiae strains were obtained by statistical control of strains technological characterization.
MATERIALS AND METHODS Sampling and Culture Conditions
Graphs represent the load of yeasts of oenological interest as determined by qPCR in the different valleys examined (log10 scale). Indigenous yeasts associated with Muscadine grapes and cider (Vitis rotundifolia).Am. 2006).The Microbiology of Wine and Vinifications: Handbook of Enology.
MATERIALS AND METHODS Strains
The analysis of amino acids in wine was carried out according to the method proposed by Ndagijimana et al. (2010, unpublished data). Regarding ketones, quantitative and qualitative differences were observed among the samples in relation to the strain used.
CONCLUSIONS
According to Falqué et al. 2002), methionol concentration was one of the variables responsible for the differentiation of wines from Loureiro, Dona Branca and Trajadura varieties from the region of Galicia (Spain). Methionol content is greatly increased in wines with reduction defects (Mestres et al., 2002), contributing to potato, cauliflower and cooked vegetable/cabbage aromas.
MATERIALS AND METHODS Yeast Strains
Taylor et al., 2014; Knight and Goddard, 2015), supporting the concept that there may be a microbial toterroir aspect. Indeed, yeast strain diversity can significantly affect fermentation performance (Schuller et al., 2012; Tofalo et al., 2014).
CONCLUDING REMARKS
In addition, the presence of other carbon sources, such as glycerol and ethyl acetate, can induce biofilm formation (Zara et al., 2010). This encourages the formation of multicellular aggregates that trap CO2 bubbles originating from the fermentation of the residual sugar, giving the aggregates buoyancy and therefore promoting biofilm formation (Zara et al., 2005) (Figure 1).
GENETIC DIVERSITY INDICATES THAT MOST FLOR YEAST SHARE THE SAME
Finally, expansion of minisatellites within the FLO11 core domain contributes to increased protein glycosylation and hydrophobicity of the yeast glycoprotein Flo11 (Flo11p) (Reynolds and Fink, 2001; Zara et al., 2005; Fidalgo et al., 2006). The presence of a single group of flora strains from different countries confirms that they have a unique origin and suggests that the yeasts migrated to Europe, as has been shown for wine yeasts worldwide (Legras et al., 2007).
ADAPTATION OF FLOR YEAST AND COPY-NUMBER VARIATIONS
Jurassic flor strains with this deletion produce thicker biofilms, while Jurassic strains with a longer FLO11 allele and a wild-type version of ICR1 produce thinner biofilms (Legras et al., 2014). This recent characterization of flor species from different countries in a single group demonstrates the ecological success of these flor species, occupying the specific niche of the wine area.
SPECIFICITIES OF FLOR YEAST
However, MCH2 and YKL222C are promising targets whose roles need to be evaluated. Further studies, such as population genomics, need to be conducted to unravel the genetic basis of yeast-flora adaptation.
FURTHER INSIGHTS FROM
PROTEOMICS AND METABOLOMICS
FLOR YEAST AS A BIOLOGICAL MODEL FOR THE STUDY OF SMALL
MOLECULES THAT INHIBIT OR PROMOTE BIOFILM FORMATION
This would lead to failure of air-liquid biofilm formation and cell adhesion. (C) Biofilm promotion. Following this hypothesis, PAF26 would act by facilitating and overcoming Flo11p-mediated interactions between cells, and thereby enhancing biofilm formation.
BIOTECHNOLOGICAL APPLICATIONS OF FLOR YEAST
A competition for nutrients was reported by Medina et al. 2014) reported a sluggish fermentation in 48h consecutive fermentation of T. cerevisiae due to nitrogen depletion by T. In a recent work, Kemsawasd et al. 2015) indicated that different nitrogen sources have different impacts on the growth and fermentation behavior of S.
CONCLUSION AND FUTURE PERSPECTIVES
The main genera or species isolated and identified were (in descending order and relative proportion of genera/species detected): Hanseniaspora uvarum, Aureobasidium pullulans, Candida, Issatchenkia, Metschnikowia and Pichia (Barata et al., 2012). We selected two species of yeasts that are often found in grape must and are involved in the fermentation process: Starmerella, which Duarte et al. 2012) and Hanseniaspora, for which strain-level discrimination was possible by Fourier transform infrared spectroscopy (FT-IR).
MATERIALS AND METHODS Grape Berry Sampling
Proportions of NS yeasts in the cellar air are variable (Ocón et al., 2013; Pérez-Martín et al., 2014) and high increases in the number and percentage of Saccharomyces were observed during the vinification period (Garijo et al., 2008). . Identification of yeast isolates was performed by Fourier-Transform Infrared (FT-IR) spectroscopy using a TensorTM 27 spectrometer coupled to an HTS-XT unit (Bruker, Ettlingen, Germany), as described by Adt et al.
RESULTS AND DISCUSSION
Thus, isolates were obtained before the arrival of the 2013 harvest in the basement environment (air, floor, equipment). On the other hand, these results show the presence of different strains of the same species in the basement environment for the first time.
MATERIALS AND METHODS Yeast Strains and Media
Yeasts mainly affect the taste of wine and produce a lot of volatile substances (Howell et al., 2006). The sensory profile was determined using nine descriptors (fruitiness, persistence, body, astringency, grassy, reduced, floral, tropical fruit, stone fruit) as previously mentioned (Suzzi et al., 2012a).
MEDIA
Considering the microbiological applications, some strategies using the genetically modified Saccharomyces cerevisiae strain have also been proposed to reduce the alcohol content in wine (Ehsani et al., 2009; Kutyna et al., 2010; Another approach to reduce the production of ethanol may be the use of non-saccharomytic wine yeasts as part of the natural microbiota present in grapes and winemaking equipment during grape juice fermentation (Renouf et al.
