Inhibitory effect of epiphytic wine grape yeasts on Alternaria alternata growth

PRENDES, L.P.; MERÍN, M.G.; RAMÍREZ, M.L.; MORATA DE AMBROSINI, V.I.

Bariloche

Simposio; ISSY34-International Specialized Symposium on Yeasts; 2018

Universidad del Comahue-CONICET

Prevention of growth of mycotogenic fungi is the most effective strategy to control thepresence of mycotoxins on foods. Alternaria is themain component of wine grape mycobiota from different winemaking regions inArgentina and worldwide. During our previous studies, Alternaria alternata strains isolated from Malbec wine grapes havedemonstrated the in vitro ability to producealternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA)and exhibited pathogenicity and TA production on wine grapes. Duringthe present study, the inhibitory effect of 14 epiphytic wine grape yeasts on mycelialgrowth of three toxicogenic and pathogenic A.alternata strains (5.5, 7.5 and 25.1) in a synthetic nutrient (SN) mediasimilar to grape composition at three different temperatures (15, 25 and 30 °C)was evaluated. All Metschnikowiaspp. yeast strains (6) completely inhibited A.alternata growth at all tested temperatures. Meanwhile, the growthinhibition exerted by Starmerellabacillaris 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 alltemperatures 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, amongthe epiphytic wine grape yeasts evaluated, Metschnikowia spp. yeast strains seems to be promising forA. alternata biological control.