Cinnamaldehyde promotes the defense response in postharvest citrus fruit inoculated with Penicillium digitatum and Geotrichum citri-aurantii

• Published in: Pesticide biochemistry and physiology 2021-11, Vol.179, p.104976-104976, Article 104976
• Main Authors: Duan, Bin, Gao, Zhouju, Reymick, Okwong Oketch, Ouyang, Qiuli, Chen, Yue, Long, Chunyan, Yang, Bao, Tao, Nengguo
• Format: Article
• Language: English
• Subjects: Cinnamaldehyde; Citrus fruit; Geotrichum citri-aurantii; Induced resistance; Penicillium digitatum
• ISSN: 0048-3575; 1095-9939
• DOI: 10.1016/j.pestbp.2021.104976

Induced resistance in harvested fruit and vegetables is a superior strategy to reduce postharvest decay. In the present study, Cinnamaldehyde (CA) was applied to investigate for its induced resistance against Penicillium digitatum and Geotrichum citri-aurantii. The results showed that 5250 mg CA/L wax was effective concentration in inducing the resistance of citrus fruit to green mold and sour rot. Wax+ CA (WCA) reduced significantly green mold and sour rot incidences at different exposure times, with 24 h being the optimal exposure time. The host reactions under infection with different pathogens were similar. During initial exposure, treatment with 5250 mg CA/L wax enhanced significantly the activities of phenylalanine ammonia-lyase (PAL), peroxidase (POD), polyphenol oxidase (PPO), β-1, 3-glucanase (GLU) and chitinase (CHT) in the presence of direct contact with the pathogen. Simultaneously, WCA induced an increase in total phenolic, flavanone and dihydroflavonol, flavone and flavonol, and lignin contents. Thus, our results suggest that treatment using 5250 mg CA/L wax can be applied early to control diseases by provoking response reactions in citrus fruit. [Display omitted] •Wax+ cinnamaldehyde (WCA) alleviated green mold and sour rot in citrus fruit.•The effect of induced resistance is dependent on the exposure time.•The induced response of citrus fruit against different pathogens is similar.•WCA increased the defense-related enzyme activities and secondary metabolites.•WCA has the potential to control diseases in citrus fruit earlier.