Abstract: This study was conducted to evaluate the effect of volatile organic compounds produced by Hanseniaspora uvarum (H. uvarum), which we have demonstrated previously to have antagonistic activity against yeast, on postharvest gray mold of strawberry fruit and the possible underlying mechanism. Results showed that fumigation treatment with 62.5 μL/L trans-cinnamaldehyde for 3 days had the best effect on controlling gray mold, significantly inhibiting the expansion of the lesion diameter (P < 0.05). In addition, trans-cinnamaldehyde at all concentrations could maintain the color, content of total soluble solid and titratable acidity of strawberry fruit and delay quality deterioration. Fumigation with 62.5 μL/L trans-cinnamaldehyde had the potential to significantly increase the activity of catalase, polyphenoloxidase, ascorbate peroxidase and β-1,3-glucanase, increase the relative expression levels of FaCAT, FaPPO, and FaAPX and delay the decrease in superoxide dismutase activity as compared with the control group. The activity of phenylalanine ammonia lyase first increased and then decreased with increasing treatment time. The relative expression level of FaPAL decreased gradually during the 3-day treatment period, while the relative expression level of FaGLU increased during the later part of this period. Overall, these results indicated that trans-cinnamaldehyde could enhance the defense-related enzymes and genes, thereby maintaining the quality and effectively inhibiting postharvest gray mold in strawberry fruit.

Key words: trans-cinnamaldehyde, strawberry, gray mold, quality, induced resistance, gene expression