Mechanisms of Action of the Yeast Hanseniaspora uvarum for the Control of the Pathogen Botrytis cinerea in Cucumber Fruit

Botrytis cinerea is a fungal pathogen that can infect healthy fruits and vegetables, causing significant economic losses through the development of gray mold disease. Over the past few decades, antagonistic yeast has been successfully employed to control this disease. In this study, an exhaustive screening process was conducted on seven yeast strains, ultimately identifying Hanseniaspora uvarum as the strain with the highest antimicrobial activity. Subsequent investigations focused on understanding its inhibitory mechanisms against cucumber gray mold. The results demonstrated that H. uvarum exhibited remarkable suppression of spore germination and germ tube elongation in B. cinerea. Most notably, H. uvarum displayed rapid colonization on the surface of cucumber fruits and effectively curbed the invasion of cucumber gray mold by inducing ROS metabolism, enhancing the activity of disease-resistant enzymes (PPO and POD) and upregulating the expression levels of relevant genes (CsPLA, CsPR1, CsCHI, and CsGLU), while promoting the accumulation of total phenolics and flavonoids. These collective actions served to maintain the storage quality of the fruits. In conclusion, H. uvarum holds significant potential in mitigating the harm caused by cucumber gray mold.