ArchivIA Università degli Studi di Catania

ArchivIA - Archivio istituzionale dell'Universita' di Catania >
Tesi >
Tesi di dottorato >
Area 07 - Scienze agrarie e veterinarie >

Please use this identifier to cite or link to this item:

Issue Date: 1-Apr-2016
Authors: Parafati, Lucia
Title: Biological control of postharvest phytopathogenic molds promoted by food-isolated yeasts
Abstract: The mechanisms of action of antagonistic food-isolated yeasts, Wickerhamomyces anomalus, Metschnikowia pulcherrima, Aureobasidium pullulans and Saccharomyces cerevisiae, were evaluated. For each yeast species, different mechanisms involved in biocontrol activity against pathogenic molds, such as iron competition, production of cell wall-degrading enzymes, production of VOCs (Volatile Organic Compounds), and biofilm formation were clarified. The second objective was to determine the efficacy of yeast strains in controlling gray mold caused by Botrytis cinerea on table grapes and strawberries, and green and blue mold decays caused by Penicillium digitatum and Penicillium italicum, respectively, on mandarin fruits. Therefore, subsequent studies investigated the potential use of locust bean gum (LBG) edible coating enriched with antagonistic yeast cells and of a commercial carrier (polyacrylammide hydrogel spheres) emitting antifungal VOCs produced by yeasts. Among tested yeast strains, W. anomalus BS91 showed great antagonistic activity both by direct application of yeast cells and by application of VOCs. This strain is known to produce killer toxins that have been demonstrated to be exoglucanases, coded by the genes WaEXG1 and WaEXG2. To better understand the involvement of these genes in the antagonist activity of W. anomalus, characterization of the gene expression level of EXG1 and EXG2 in different yeast-host-pathogen interactions was carried out. The present study demonstrated the efficacy of the selected yeasts as postharvest antifungal agents both by direct application and incorporation in an edible coating (LBG). Moreover, it has been demonstrated as production of VOCs can play an essential role in the antagonistic activity of BCAs, suggesting a future use of polyacrylammide hydrogel beads as VOCs emitters during the shelf-life.
Appears in Collections:Area 07 - Scienze agrarie e veterinarie

Files in This Item:

File Description SizeFormatVisibility
PRFLCU86S49I639W-Parafati PhD thesis.pdfLucia Parafati PhD thesis3,83 MBAdobe PDFView/Open

Items in ArchivIA are protected by copyright, with all rights reserved, unless otherwise indicated.

Share this record




Stumble it!



  Browser supportati Firefox 3+, Internet Explorer 7+, Google Chrome, Safari

ICT Support, development & maintenance are provided by the AePIC team @ CILEA. Powered on DSpace Software.