Screening of yeasts in vitro to biocontrol Aspergillus carbonarius isolated from natural olives

PESCE V.M.; GUERRA G.B.; NALLY M.C; TORO M.E. ; CASTELLANOS DE FIGUEROA L.I.; VAZQUEZ F.

San Juan

Otro; 2da Reunión Conjunta de Sociedades de Biología de la República Argentina; 2011

San Juan is one of the main olives producers in Argentina. Olea europea (L.) is affected by Aspergillus sp. Dominance and antibiosis of yeasts against A. carbonarius (A.c.) were evaluated. Microorganisms: 59 grape pathogenic fungi biocontrol yeasts and 2 isolates of A.carbonarius from natural olives. Dominance Index: yeasts and fungi were inoculated in dual cultures (Malt Extract Agar: MEA). Interaction was evaluated by numerical scores: 1 (mutual intermingling); 2 (mutual inhibition on contact); 3 (mutual inhibition at distance); 4(dominance on contact); 5 (dominance at distance). Antibiosis: 108 cells.ml-1 yeasts (10μl) were inoculated in equidistant wells of MEA. Fungi mycelium was seeded in the centre of the plate. Inhibitory effect of yeasts on fungi growth was observed (halos). Most yeast showed Index 2: 63% against A.c.I and 42% against A.c.II. Index 5 was observed in four yeasts against A.c.I and only one against A.c.II. Torulaspora delbrueckii Td129 reduce 64.5% growth of A.c.I and Pichia membranifaciens BPm6 reduce 52.7% growth of A.c.II. No yeasts showed antibiosis against A. carbonarius I and II. Biocontrol yeasts of pathogenic fungi of grapes could be potential antagonists of A. carbonarius in olives. Dominance of these yeasts against A. carbonarius was determined.