INHIBITORY EFFECT OF EPIPHYTIC WINE GRAPE YEASTS ON ALTERNARIA ALTERNATA GROWTH

LUCIANA PAOLA PRENDES; MARIA GABRIELA MERIN; MARIA LAURA RAMIREZ; VILMA I. MORATA DE AMBROSINI

Simposio; International Specialized Symposium on Yeast ISSY34; 2018

Prevention of growth of mycotogenic fungi is the most effective strategy to control the presence of mycotoxins on foods. Alternaria is the main component of wine grape mycobiota from different winemaking regions in Argentina and worldwide. During our previous studies, Alternaria alternata strains isolated from Malbec wine grapes have demonstrated the in vitro ability to produce alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) and exhibited pathogenicity and TA production on wine grapes. During the present study, the inhibitory effect of 14 epiphytic wine grape yeasts on mycelial growth of three toxicogenic and pathogenic A. alternata strains (5.5, 7.5 and 25.1) in a synthetic nutrient (SN) media similar to grape composition at three different temperatures (15, 25 and 30 °C) was evaluated. All Metschnikowia spp. yeast strains (6) completely inhibited A. alternata growth at all tested temperatures. Meanwhile, the growth inhibition exerted by Starmerella bacillaris yeast strains (3) was variable upon assayed conditions. All yeast strains inhibited A. alternata 5.5 growth at 25 °C and 30 °C, one of them inhibited A. alternata 7.5 and 25.1 growth at all temperatures and the other two inhibited A. alternata 7.5 and 25.1 growth only at 30 °C. Finally, only one of the Hanseniaspora uvarum yeast strains (5) evaluated showed an inhibitory effect on the three A. alternata strains growth but only at 30 °C. In conclusion, among the epiphytic wine grape yeasts evaluated, Metschnikowia spp. yeast strains seems to be promising for A. alternata biological control.