Effect of Yarrowia lipolytica on postharvest decay of grapes caused by Talaromyces rugulosus and the protein expression profile of T. rugulosus

Biological control of pathogens using biocontrol agents has been document to be an effective and safe method for managing postharvest diseases. A better understanding of the mode of action of postharvest biocontrol agents on fruit surfaces, is critical for the advancement of successful implementation of postharvest biocontrol products. We investigated the biocontrol efficacy of Yarrowia lipolytica against the postharvest decay of table grapes caused by Talaromyces rugulosus and the possible mechanisms involved. Y. lipolytica significantly decreased the decay incidence of the treated grape berries compared to the untreated control. The response of T. rugulosus to different components of Y. lipolytica indicated that only the yeast cells exhibited inhibitory effect on fungal mycelium, while extracellular metabolites did not show any significant effect on T. rugulosus. The in vitro experiment showed that Y. lipolytica significantly inhibited spores germination and lesion diameter caused by T. rugulosus. We observed that the grape wounds were rapidly colonized by the antagonistic yeast at 25 °C and 4 °C. Thirty-five differential proteins were identified in T. rugulosus out of which 31 were down-regulated. Majority of the down-regulated proteins were related to basic metabolism, which suggested that the basic metabolism of T. rugulosus was suppressed.