Control of Penicillium glabrum by Indigenous Antagonistic Yeast from Vineyards

Abstract

Biocontrol is one of the most promising alternatives to synthetic fungicides for food preservation. <i>Botrytis cinerea</i>, <i>Alternaria alternata,</i> and <i>Aspergillus</i> section <i>Nigri</i> are the most concerning pathogens for grape development. However, frequently, other species, such as <i>Penicillium glabrum</i> in this study, are predominant in spoiled bunches. In this work, 54 native yeasts from vineyards were screened by direct confrontation in potato dextrose agar plates as antagonists against <i>P. glabrum</i>. Isolates of <i>Pichia terricola</i>, <i>Aureobasidium pullulans</i>, and <i>Zygoascus meyerae</i> were selected for their antagonist activity in vitro, plus isolates of <i>Pichia kudriavzevii</i>, <i>Hormonema viticola,</i> and <i>Hanseniaspora uvarum</i> were used as negative controls. However, in vivo, confrontations in wounded grapes showed disagreement with direct confrontation in vitro. <i>P. terricola</i>, <i>P. kudriavzevii</i>, <i>H. viticola</i>, <i>Z. meyerae,</i> and <i>H. uvarum</i> significantly reduced the incidence of <i>P. glabrum</i> on grapes. Nevertheless, <i>P. terricola</i>, <i>H. viticola,</i> and <i>H. uvarum</i> themselves spoiled the wounded grapes. Inhibitions were associated with different mechanisms such as the production of volatile organic compounds (VOCs), lytic enzymes, biofilm formation, and competition for nutrients. The isolates of <i>P. kudriavzevii</i> L18 (a producer of antifungal VOCs which completely inhibited the incidence of <i>P. glabrum</i>) and <i>Z. meyerae</i> L29 (with pectinase, chitinase and β-glucanase activity and biofilm formation which reduced 70% of the incidence of <i>P. glabrum</i>) are proposed as suitable biocontrol agents against <i>P. glabrum</i>.