Search Results (10)

The cultivation of ‘Shine Muscat’ grapes is rapidly expanding in East Asia due to their desirable qualities and muscat flavor. Studies have revealed that storing these grapes at an controlled freezing-point temperature diminishes their muscat flavor, whereas storage at 10 °C preserves it. However, the impact of a higher storage temperature on the evolution of microbial communities remains unclear. This study aimed to analyze the mycobiota dynamics of ‘Shine Muscat’ grape bunches under different cold storage temperatures. A total of 1,892,842 and 1,643,200 sequences were obtained from berries and pedicels, identifying over 208 fungal genera from 6 phyla. Xylariaceae was the most abundant family, with a prevalence between 7.21% and 69.27% across all sample groups. The primary genera included Zygosporium, Cladosporium, Aspergillus, Acremonium, Podosordaria, Zasmidium, Penicillium, and Alternaria. Spoilage-related fungi varied with storage temperature, with Aspergillus, Penicillium, and Alternaria being dominant at 0 °C and Cladosporium, Aspergillus, Penicillium, and Alternaria being prevalent at 10 °C. The fungal profiles of berries and pedicels differed significantly, and storage temperature further influenced these variations. Our findings highlight distinct fungal diversity and spoilage patterns in ‘Shine Muscat’ grape bunches from the Nanning region compared to those grown in temperate areas, revealing the unique microbial evolution of grape bunches stored at different temperatures in Nanning. Full article

Grape skin serves as a reservoir for many bacteria and fungi, which can affect grape health, quality, and safety. However, grape skin microbiota and mycobiota of table grapes remain largely understudied. This study investigated bacterial and fungal communities residing on different table grapevine cultivars (‘Summer Black’ and ‘Kyoho’) as well as the impact of potential contributors thereby, via culture-dependent and culture-independent (analysis of 16S rRNA gene and internal transcribed spacer sequences) methods with different purposes. Microbiota of both grapevine cultivars were dominated by Cladosporium, Alternaria, Aspergillus, Thauera, and Pantoea. In addition, yeast strains belonging to Hanseniaspora opuntiae, Pichia terricola, Rhodotorula mucilaginosa, Candida stellimalicola, and Kodamaea ohmeri were enriched from the studied grapes, while some strains were considered as health-threatening pathogens. Differences in grapevine cultivars did not significantly affect their mycobiota and microbiota profiles. Nevertheless, their mycobiota exhibited significant variations across different grape-sampling sites in Shanghai, indicating the contribution of the grape-growing environment to grape skin mycobiota. Altogether, the current study demonstrated the contribution of the grape-growing environment to table grape skin mycobiota, and highlighted the importance of microbiota management in the production and consumption of table grapes. Full article

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 vines subjected to the phytostimulant BION^®50WG treatment. This work was carried out in the CREA-VE experimental vineyard of Vitis vinifera cv. Barbera in Asti (Piedmont, Italy). The composition of fungal communities on grapes from three experimental conditions such as IPM (integrated pest management), IPM+BION^®50WG, and IPM+water foliar nebulization was compared by a metabarcoding approach. Our results revealed the magnitude of alpha and beta diversity, and the microbial biodiversity index and specific fungal signatures were highlighted by comparing the abundance of yeast and filamentous fungi in IPM and BION^®50WG treatments. No significant differences in the mycobiota of grapevines subjected to the three treatments were detected. Full article

Viticulture is one of the traditional industries in Slovakia, where there are six wine-growing regions: Malokarpatska, Southern Slovakia, Central Slovakia, Nitra, Eastern Slovakia, and Tokaj. This study focuses on the detection of microbiota in soil samples, grape leaves and berries, and samples taken from fermenting must and young wine (the variety Tramín červený) in relation to the detected concentrations of biogenic amines during the fermentation process. In the examined samples, the number of yeasts and molds (from 3.8 to 6.8 log cfu/g or mL) and TVC (from 3.7 to 6.5 log cfu/g or mL) were determined via culture examination. At the same time, the number of LAB (from ˂3.0 to 4.4 log cfu/g or mL) was determined, which was the highest on day 4 of the must fermentation process and was related to the detected of the highest concentration of biogenic amines (histamine and tyramine) on day 6 in the investigated must samples using the UHPLC system. Mycobiota species were identified by MALDI-TOF MS, PCR, ITS-PCR-RFLP, and PCR sequencing of the amplified products. The study confirmed the presence of the yeasts Saccharomyces cerevisiae, Metschnikowia pulcherrima, Hanseniospora uvarum, Pichia kudriavzevii, Pichia kluyveri, Pichia fermentas, Torulaspora delbrueckii, and Candida tenuis. At the same time, the presence of molds (Cladosporium herbarum, Cladosporium cladosporioides, Penicillium granulatum, Penicillium mononematosum, Botritis cinerea, and Penicillium glabrum) was also confirmed in soil samples, leaves, grape berries, and fresh grape must. The study confirmed the reduction in the species diversity of the microbiota during the must fermentation process, which resulted in decreases in the concentrations of the monitored biogenic amines in the early stages of the must fermentation process and young wine of the variety Tramín červený. Full article

Winemaking is a well-known process that includes several steps in the production of grape must and wine. Grape marc, or bagasse, is a byproduct of wine production that can be vermicomposted and used as organic fertilizer. Grape marc vermicompost has microbial communities that are richer and more stable than grape marc alone, and its addition to a vineyard’s terroir can improve grape yields and wine quality. Here we compare the must and wine microbiota of Mencía from grapevines treated with and without (standard fertilization) vermicompost derived from Mencía grape marc. Mencía is a high-quality red wine broadly grown in Galicia, Spain, and is appreciated for its fresh acidity and fruity flavors. When Mencía grapevines are treated with vermicompost derived from its grape marc, Mencía vines increase their grape production, and the final wine improves its organoleptic properties. Metataxonomic analyses of the bacterial 16S rRNA and fungal ITS gene regions showed that Mencía must and wine have the distinct taxonomic composition (phyla, genera and ASVs—amplicon sequence variants) of bacterial and fungal groups. Must and wine bacteriotas and mycobiotas show no significant variation in alpha-diversity, while wine bacteriotas and mycobiotas show significant differences in microbial structure (beta-diversity) between treated and control grapevines. Likewise, the functional diversity and predicted metabolic pathways (biosynthesis, degradation/utilization/assimilation, generation of precursor metabolites and energy, macromolecule modification and superpathways) of the must and wine microbiota also show significant changes. Our study proposes that changes in the abundance of microbial taxa and the metabolic processes they undergo during winemaking may improve Mencía’s organoleptic properties and productivity. Full article

In this study, the evolution of the yeast microflora present on the berry surface, during the ripening of Barbera grapes, was monitored. Sampling was performed in three vineyards located in the “Nizza” Barbera d’Asti DOC zone and different methodologies have been employed. A culture-dependent method based on the identification of strains grown on solid media by ARDRA (Amplified Ribosomal DNA Restriction Analysis) and the D1-D2 domain of ribosomal 26S DNA capillary sequencing was coupled to NGS (Next Generation Sequencing) targeting ITS (Internal Transcribed Sequence) amplicons with the Illumina MiSeq platform. By using culture-dependent techniques, the most frequently detected species was the yeast-like fungus Aureobasidium pullulans, which was dominant in the culturable fraction. Among yeasts, the presence of oligotrophic basidiomycetes such as Cryptococcus spp., Rhodotorula graminis and Sporidiobolus pararoseus was observed at the beginning of ripening. Afterward, upon approaching the harvest, a succession of oxidative or weakly fermentative copiotrophic species occurs, such as Saturnispora diversa, Issatchenkia terricola, Hanseniaspora opuntiae, Starmerella bacillaris and Hanseniaspora uvarum. The massive sequencing revealed a larger number of species, respect to the culture-dependent data. Comparing the two different approaches used in this work, it is possible to highlight some similarities since Aureobasidium, Rhodotorula and Sporobolomyces were detected by both methods. On the contrary, genera Hanseniaspora, Issatchenkia and Saturnispora were revealed by culture-dependent methods, but not by NGS, while Saccharomyces spp. were identified, with low frequency, only by NGS. The integrated application of NGS sequencing and culture-dependent techniques provides a comprehensive view of mycodiversity in the wine-growing environment, especially for yeasts with low abundance. Full article

The species richness and composition of macro- and microfungi on vine species in the parks of Ekaterinburg City (the Ural macroregion, Russia) located in the southern boreal vegetation subzone in a continental climate was studied. The average annual air temperature has increased by 3.1 °C since the beginning of the 20th century; therefore, the conditions for the growth of vines have improved. These conditions include warmer winters and, consequently, less frost damage to perennial plants. Due to the warmer climate, the area of vines grown in the city has increased five times over half a century, and the yield of grapes has grown 3.7 times. The alien East Asian vines are the most dominate vine species cultivated, while European, North American, and native plant species, including archaeophytes, together only represent a handful of the species cultivated. At the same time, 65% of the area of woody vines in the city is covered by a North American species, namely Parthenocissus quinquefolia. An increase in the number of vine species, their biomass, and covered areas contributes to an increase in the number of fungal species growing on these vine species. In total, 81 species of phytopathogenic and 87 species of saprobic macro- and microfungi have been recorded during the century-long history of mycological research in Ekaterinburg City. Mycobiota of vines in Ekaterinburg City is biogeographically heterogeneous and 1.1–3.2 times richer in comparison with ones of the regions located on the northern limit of natural ranges of the vines. Recorded macrofungi (Basidiomycota) are predominantly present on native boreal species; however, some exotic tropical and subtropical East Asian fungal species (that have not ever been recorded on other substrates in the natural forests of the Urals and Siberia) are found here too. Recorded microfungi are highly specialized vine-associated species (mainly Ascomycota) that are widespread within the natural ranges of the vines and absent in the boreal zone of Eurasia: there are 63 vine-associated species (15 macro- and 48 microfungi) in Ekaterinburg that are not found in the Urals on other substrates. Many of these species have been recorded for the first time in this study, so we consider that they invaded Ekaterinburg City in the last 20 years, likely due to the warming climate observed over the last decades in the region. There are 19 and 32 species of phytopathogenic fungi collected in the families Cucurbitaceae and Vitaceae, respectively. During the past 40 years, the recorded fungal species richness has increased by 16% on Cucurbitaceae, as well as 37% on grapes. In this study, the distribution of vine-associated fungi, including phytopathogenic fungal species, from the nearest regions of ancient vine culture (Southern European Russia and the Caucasus, Central Asia, the south of the Russian Far East) to the boreal regions of the Urals were investigated. The increase in the range of these phytopathogenic fungal species can lead to significant economic losses to the regional agricultural sector. Full article

The occurrence of mycotoxins on grapes poses a high risk for food safety; thus, it is necessary to implement effective prevention methods. In this work, a metagenomic approach revealed the presence of important mycotoxigenic fungi in grape berries, including Aspergillus flavus, Aspergillus niger aggregate species, or Aspergillus section Circumdati. However, A. carbonarius was not detected in any sample. One of the samples was not contaminated by any mycotoxigenic species, and, therefore, it was selected for the isolation of potential biocontrol agents. In this context, Hanseniaspora uvarum U1 was selected for biocontrol in vitro assays. The results showed that this yeast is able to reduce the growth rate of the main ochratoxigenic and aflatoxigenic Aspergillus spp. occurring on grapes. Moreover, H. uvarum U1 seems to be an effective detoxifying agent for aflatoxin B₁ and ochratoxin A, probably mediated by the mechanisms of adsorption to the cell wall and other active mechanisms. Therefore, H. uvarum U1 should be considered in an integrated approach to preventing AFB₁ and OTA in grapes due to its potential as a biocontrol and detoxifying agent. Full article

The present study evaluated the impact of organic and conventional fungicide treatments compared with untreated samples (no fungicides were used) on the grape berry yeast community of the Montepulciano variety. The yeast dynamics during the spontaneous fermentation using culture-dependent and -independent methods was also evaluated. Results showed a reduction of yeast biodiversity by conventional treatments determining a negative influence on fermenting yeasts in favor of oxidative yeasts such as Aerobasidium pullulans. Starmerella bacillaris was significantly more present in organic samples (detected by next generation sequencing (NGS)), while Hanseniaspopa uvarum was significantly less present in untreated samples (detected by the culture-dependent method). The fermenting yeasts, developed during the spontaneous fermentation, were differently present depending on the fungicide treatments used. Culture-dependent and -independent methods exhibited the same most abundant yeast species during the spontaneous fermentation but a different relative abundance. Differently, the NGS method was able to detect a greater biodiversity (lower abundant species) in comparison with the culture-dependent method. In this regard, the methodologies used gave a different picture of yeast dynamics during the fermentation process. The results indicated that the fungal treatments can influence the yeast community of grapes leading must fermentation and the final composition of wine. Full article

Mycotoxigenic fungi colonizing food matrices are inevitably competing with a wide range of other resident fungi. The outcomes of these interactions are influenced by the prevailing environmental conditions and the competing species. We have evaluated the competitiveness of F. culmorum and A. carbonarius in the grain and grape food chain for their in vitro and in situ dominance in the presence of other fungi, and the effect that such interactions have on colony interactions, growth and deoxynivalenol (DON) and ochratoxin A (OTA) production. The Index of Dominance shows that changes in water activity (a_w) and temperature affect the competitiveness of F. culmorum and A. carbonarius against up to nine different fungi. Growth of both mycotoxigenic species was sometimes inhibited by the presence of other competing fungi. For example, A. niger uniseriate and biseriate species decreased growth of A. carbonarius, while Aureobasidium pullulans and Cladosporium species stimulated growth. Similar changes were observed when F. graminearum was interacting with other grain fungi such as Alternaria alternata, Cladopsorium herbarum and Epicoccum nigrum. The impact on DON and OTA production was very different. For F. culmorum, the presence of other species often inhibited DON production over a range of environmental conditions. For A.carbonarius, on a grape–based medium, the presence of certain species resulted in a significant stimulation of OTA production. However, this was influenced by both temperature and a_w level. This suggests that the final mycotoxin concentrations observed in food matrices may be due to complex interactions between species and the environmental history of the samples analyzed. Full article