cAMP-induced Sporidiobolus pararoseus Y16 alleviates postharvest sour rot of grapes and the potential action mechanisms

Sour rot caused by Aspergillus carbonarius is a common postharvest disease of grapes, which leads to the declined fruit quality and serious economic losses of grape industry. In this study, we investigated the control effectiveness of Sporidiobolus pararoseus Y16 induced by cyclic adenosine monophosphate (cAMP) against postharvest sour rot of grapes, and explored the potential action mechanisms. The outcomes presented that S. pararoseus Y16 induced by 0.05 mM cAMP for 24 h further mitigated sour rot compared with S. pararoseus Y16 cultured without cAMP. cAMP could enhance the colonization ability of S. pararoseus Y16. More importantly, cAMP-induced yeast further boosted the activities of antioxidant enzymes and the expression level of the corresponding genes, thus improving the ability of scavenging reactive oxygen species of grapes. Moreover, S. pararoseus Y16 induced by cAMP further mounted the activities of defensive enzymes in grapes, as well as the expression level of the corresponding genes, thereby strengthening the disease resistance of grapes. Additionally, the accumulation of resistant secondary metabolites was further augmented, which also contributed to improving the disease resistance of grapes. This research revealed that cAMP-induced culture is helpful to improve the effectiveness of S. pararoseus Y16 in controlling postharvest sour rot of grapes. This research provides a novel and effective biocontrol strategy for the grape industry to mitigate postharvest sour rot. By using cAMP-induced antagonistic microorganisms, the reliance on chemical fungicides could be potentially reduced, thereby promoting sustainable agricultural practices and enhancing the overall quality and safety of grape products.