Physiological and transcriptomic insights deciphering cAMP-induced oxidative stress tolerance of antagonistic yeast Sporidiobolus pararoseus Y16

Aspergillus carbonarius- induced sour rot is an important postharvest disease affecting grapes. Previous study demonstrated that cAMP induction boosts the biocontrol efficiency of Sporidiobolus pararoseus Y16 in combating postharvest sour rot of grapes. Oxidative stress experienced by the antagonistic yeast at fruit wound sites is a key factor limiting its biocontrol efficacy. This research investigated how inducing yeast cells with cAMP effects on tolerance to oxidative stress and explored underlying mechanisms. Results showed that cAMP treatment significantly increased yeast survival rate under exogenous oxidative stress. Physiological analysis revealed a synergistic enhancement on enzyme activities, such as SOD, POD, and CAT in cAMP-induced yeast, accompanied by reduced levels of reactive oxygen species (ROS) under H 2 O 2 stress in vitro and at grape wound sites. Furthermore, levels of protein carbonylation, malondialdehyde (MDA) and trehalose were decreased. Transcriptomic analysis identified upregulation of key genes involved in one-carbon metabolism, thiamine biosynthesis, and amino acid metabolism, such as MTHFR , THI5 , ALDH7A1 , CTH , and proB, which collectively promoted NADPH regeneration, glutathione (GSH) synthesis, aldehyde detoxification, and direct ROS scavenging. In conclusion, cAMP induction activates a multilayered antioxidant defense system in S. pararoseus Y16 through metabolic reprogramming, significantly enhancing its adaptability to the oxidative stress microenvironment of grapes. These findings provide a theoretical basis for optimizing the performance of biocontrol yeasts, demonstrating their significant application prospects.