Isolation, identification and selection of antagonistic yeast against Alternaria alternata infection and tenuazonic acid production in wine grapes from Argentina

LUCIANA P. PRENDES; MARÍA G. MERÍN; ARIEL R. FONTANA; RUBÉN AMBROSIO BOTTINI; MARÍA L. RAMIREZ; VILMA I. MORATA DE AMBROSINI

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018 vol. 266 p. 14 - 20

0168-1605

Epiphytic isolates with yeast characteristics from grapes of the Malbec cultivar were obtained in order to findantagonists against Alternaria alternata. From a total of 111 isolates, 82% corresponded to the yeast-like organismAureobasidium pullulans and the rest to the non-Saccharomyces yeasts Hanseniaspora uvarum (6.3%),Metschnikowia pulcherrima or spp. (5.4%), Cryptoccocus laurentti II (2.7%), Starmerella bacilaris or Candida zemplinina(2.7%) and Rhodotorula spp. (0.9%). The 22.4% (15 out of 67) of epiphytic yeasts and yeast-like organismsevaluated were able to reduce A. alternata infection from 0.0 to 4.4% when applied 2 h previous topathogen inoculation on wounds of grape berries. From these selected strains, 14 out of 15 strains completelyprevented A. alternata infection (0.0%), which implies potential for field application. All Metschnikowia (pulcherrimaor spp.), S. bacillaris and almost all H. uvarum evaluated strains showed antagonist capability against A.alternata. Meanwhile, none of the lesser nutritional requirement strains belonging to A. pullulans, Cr. laurenti IIand Rhodotorula spp. did. All the yeasts with capacity to prevent A. alternata infection also reduced tenuazonicacid (TA) production by 81.2 to 99.8%, finding TA levels similar to negative controls. Therefore, the epiphyticyeasts selected are promising as biological control agents against Alternaria infection and toxin production ingrapes for winemaking.