Jun 23, 2020 | Grape and wine microorganisms: diversity and adaptation, IVES Conference Series, OENO IVAS 2019
Developments in high-throughput sequencing (HTS) technologies allow us to obtain large amounts of microbial information from wine and must samples. Thus approaches, that are aimed at characterising the microbial diversity during fermentation, can be enhanced, or possibly even replaced, with HTS-based metabarcoding. To reduce experimental biases and increase data reproducibility, we compared 3 DNA extraction methods by evaluating differences in the fungal diversity with Riesling alcoholic fermentation samples at four different vineyards. The fungal diversity profiling was done using the genetic markers ITS2 and D2 using metabarcoding. The extraction methods compared consisted of a commercial kit, a recently published protocol that includes a DNA enhancer, and a protocol based on a buffer containing common inhibitor removal reagents. All methods were able to distinguish vineyard effects on the fungal diversity, but the results differed quantitatively.
Jun 23, 2020 | Grape and wine microorganisms: diversity and adaptation, IVES Conference Series, OENO IVAS 2019
Extracellular substances (ECS) represent all molecules outside the cytoplasmic membrane, which are not directly anchored to the cell wall of microorganisms living through a planktonic or biofilm phenotype. They are the high-biomolecular-weight secretions from microorganisms (i.e. extracellular polymeric substances – EPS – proteins, polysaccharides, humic acid, nucleic acid), and the products of cellular lysis and hydrolysis of macromolecules. In addition, some high- and low-molecular-weight organic and inorganic matters from environment can also be adsorbed to the EPS. All can be firmly bound to the cell surface, associated with the EPS matrix of biofilm, or released as being freely diffusing throughout the medium.
Jun 23, 2020 | IVES Conference Series, Soil Assessment and Management and Geological Influences on Terroir Development, Terroir 2016
Wine-grapes in the Willamette Valley, Oregon, are grown on three major soil parent materials: volcanic, marine sediments, and loess/volcanic.
Jun 23, 2020 | Grape and wine microorganisms: diversity and adaptation, IVES Conference Series, OENO IVAS 2019
In winemaking, several antimicrobial peptides (AMPs) produced by different strains of Saccharomyces cerevisiae were found to be responsible for the inhibition of malolactic fermentation (MLF) carried out by some strains of Oenococcus oeni. However, only two AMPs produced by one of the yeast strains studied were totally identified and their mechanism of action was described. In an attempt to identify new AMPs, a 5-10 kDa peptidic fraction produced by an oenological strain of S. cerevisiae and previously shown to strongly inhibit MLF carried out by a strain of O. oeni was further purified.
Jun 23, 2020 | IVES Conference Series, Soil Assessment and Management and Geological Influences on Terroir Development, Terroir 2016
Wines differ from each other based on seven different factors: the type of grape; the bedrock geology and resulting soils; the climate; the soil hydrology; physiography of the site; the winemaker and the vineyard management techniques. The first five of these factors make up what the French call terroir, “the taste of the place”.
