Pichia angusta is an effective biocontrol yeast against postharvest decay of apple fruit caused by Botrytis cinerea and Monilia fructicola.

The efficacy of eight isolates of Pichia angusta against three common postharvest pathogens of apple fruit was evaluated for the first time. All tested strains showed significant biocontrol activity against both Botrytis cinerea and Monilia fructicola, whereas efficacy against Penicillium expansum was poor. A leucine-auxotrophic mutant had no significant biocontrol activity against brown rot of apple, while the addition of 0.6-1.2 g L(-1) leucine in the fruit wound fully restored the biocontrol activity of this mutant against M. fructicola. Given the extremely well-developed classical and molecular genetics, the availability of genomic libraries, and its complete genomic sequence, this species can serve to elucidate the mechanisms related to biocontrol capacity.