Biocontrol of gray mold in grapes with the yeast Hanseniaspora uvarum alone and in combination with salicylic acid or sodium bicarbonate

• SA at 2 mmol L−1 and SBC at 2% were found to enhance the biocontrol efficacy of H. uvarum.
• SA and SBC contribute to promoting the appearance of grapes.
• Integration of H. uvarum with SA or SBC maintained fruit quality indicators.
• H. uvarum in combination with SA or SBC resulted in higher enzyme activities than in the control group.
• Enhanced control by SA or SBC could be either by induced resistance or direct effects on Botrytis.

The yeast Hanseniaspora uvarum alone or in combination with salicylic acid or sodium bicarbonate was investigated for control of gray mold, postharvest quality and antioxidant enzymes of grapes. The results indicated that the treatment of H. uvarum suspension of 1 × 108 CFU mL−1 combined with either 2 mmol L−1 SA or 2% SBC resulted in a remarkably improved control of Botrytis cinerea infections on grapes. Disease incidence and lesion diameter in treated fruit by H. uvarum alone or combined with SA or SBC were significantly lower than those of the control fruit (P < 0.05) at 25 °C, RH 90–95%. Integration of H. uvarum with SA and with SBC both significantly reduced the browning index, the decay incidence, weight loss while maintained the fruit appearance, firmness, total soluble solids (TSS) and titratable acidity (TA) of the grapes (P < 0.05) at 2 ± 1 °C, RH 90–95%. Furthermore, the combination of yeast and aforementioned chemicals led to increases of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonia lyase (PAL), ascorbate peroxidase (APX) and polyphenoloxidase (PPO) activities. Enhanced control by SA or SBC could be due to either induced resistance or direct effects of these chemicals on Botrytis. The proper combination of H. uvarum and chemical reagent can thus provide an effective strategy to reduce postharvest decay of grape berries.