Researchers from the University of Environmental and Biological Sciences of Wroclaw (Poland), and from the University of Catania, have tested, in vitro, the antagonistic effects of some yeasts (Debaryomyces hansenii KI2a, Debaryomyces hansenii MI1a and Wickerhamomyces anomalus BS91) against Monilinia fructigena and Monilinia fructicola, responsible for brown rot in stone fruit.
Tests showed that all yeast strains have a different antifungal activity, depending on species, strain and pathogen.
D. hansenii KI2a and W. anomalus BS91, had the highest biocontrol activity in vitro. It was hypothesised that their main mechanisms of action against pathogens are the production of hydrolytic enzymes, killer toxins and volatile organic compounds.
Yeasts D. hansenii KI2a and W. anomalus BS91 significantly reduced brown rot incidence and severity on peach and plum fruits artificially inoculated with M. fructigena and M. fructicola, especially when applied 24 hours before pathogen inoculation.
On the other hand, D. hansenii MI1a showed a weak antagonistic activity against M. fructigena on peaches and plums, and was ineffective against M. fructicola. The noticeable ability of W. anomalus BS91 to control brown rot could be also correlated with its high capacity to colonise the wound tissue and increase its population density.
Researchers concluded that "antagonist strains D. hansenii and W. Anomalus, could become active principles for the development of biofungicides against the Monilinia species, responsible for considerable economic losses in stone fruit crops."
Source: Monika Grzegorczyk, Barbara Zarowska, Cristina Restuccia, Gabriella Cirvilleri, 'Postharvest biocontrol ability of killer yeasts against Monilinia fructigena and Monilinia fructicola on stone fruit', 2017, Food Microbiology, Vol. 61, 93-101.
www.sciencedirect.com/science/article/pii/S0740002016306128