Inhibitory Effect and Potential Antagonistic Mechanism of Isolated Epiphytic Yeasts against Botrytis cinerea and Alternaria alternata in Postharvest Blueberry Fruits

Abstract

This study evaluated the biocontrol effect of isolated epiphytic yeasts (<i>Papiliotrema terrestris, Hanseniaspora uvarum</i>, and <i>Rhodosporidium glutinis</i>) against <i>Botrytis cinerea</i> and <i>Alternaria alternata</i> in blueberry fruits and its possible mechanisms. Our findings indicated that the three tested yeasts exerted a good biocontrol effect on postharvest diseases in blueberry, and that <i>H. uvarum</i> was the most effective. In addition, the three tested yeasts could improve the postharvest storage quality of blueberry fruits to some extent. <i>H. uvarum</i> demonstrated the strongest direct inhibitory effect on pathogens by suppressing spore germination, mycelial growth, and antifungal volatile organic compound (VOC) production. <i>P. terrestris</i> showed the highest extracellular lytic enzymes activities. It also had better adaptation to low temperature in fruit wounds at 4 °C. The biofilm formation capacity was suggested to be the main action mechanism of <i>R. glutinis</i>, which rapidly colonized fruit wounds at 20 °C. Several action mechanisms are employed by the superb biocontrol yeasts, while yeast strains possess distinctive characteristics and have substantially different action mechanisms.