Evaluation of pathogenicity factors in biocontrol yeasts Kluyveromyces thermotolerans Isolated from Argentinean vineyards.

NALLY M. C; PONSONE M.L; TORO M.E; VAZQUEZ, F; CHULZE , S.N

Martina Franca

Congreso; ISM MycoRed International Conference Europe 2013. Global Mycotoxin Reduction Strategies; 2013

ism

Biological control using yeast has been proposed as a strategy to reduce the impact of ochratoxigenic fungal species in vineyards. Pathogenicity factors of the selected biocontrol agents need to be tested since numerous cases of clinical infections caused by yeasts have been reported in the literature in recent years, particularly in immune-compromised patients. Some fungal properties are frequently associated with pathogenesis, like the ability to grow at high temperatures, to adhere and invade host cells and to secrete degradative enzymes such as proteinases and phospholipases. The aim of this study was: -To evaluate pathogenic factors related with humans of two potential biocontrol yeast strains, Kluyveromyces thermotolerans RCKT4 and RCKT5 isolated from wine grapes in Argentina.- The production of phospholipases, proteases, pseudohypha formation, growth at 37 °C and 42 ° C, invasive growth were evaluated, Candida albicans ATCC10231, was used as positive control in all the pathogenicity assays. The two potential biocontrol yeast strains, K. thermotolerans RCKT4 and RCKT5 grew at 37 °C, while they did not grow at 42 °C. Non pseudohyphal formation, invasive growth, phospholipase and proteolityc activities were detected in either of the two K. thermotolerans strains evaluated. These results are promising because they showed the possibility to use these biocontrol agents, non human pathogenic as a tool to reduce the impact of ochratoxigenic Aspergillus species and ochratoxin accumulation in grapes.