Anthocyanins contribute to fruit defense against postharvest green mold

• Published in: Postharvest biology and technology 2021-11, Vol.181, p.111661, Article 111661
• Main Authors: Lin, Yunlong, Fan, Liqin, He, Jiaxin, Wang, Zhongkang, Yin, Youping, Cheng, Yulin, Li, Zhengguo
• Format: Article
• Language: English
• Subjects: Accumulation; Anthocyanins; Biosynthesis; Blood orange; Citrus fruits; Disease resistance; Fruit resistance; Fruits; Fungi; Gene expression; Green mold; Health promotion; Infections; Metabolites; Mold; Oranges; Pathogens; Penicillium digitatum; Plant resistance; Post-harvest decay; Reactive oxygen species; ROS; Secondary metabolites; Stresses; Transcriptomes
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2021.111661

•Compared with other oranges, Tarocco showed increased resistance to green mold.•Penicillium digitatum (Pd) infection induced anthocyanin accumulation in Tarocco.•Anthocyanin treatment reduced the susceptibility of citrus fruit to Pd.•Reactive oxygen species was affected in anthocyanin-treated fruit.•Differentially expressed genes were identified in Tarocco upon Pd infection. Anthocyanins, an important class of pigmented and health-promoting plant secondary metabolites, are involved in protecting plants from stresses. However, the contribution of anthocyanins in plant resistance to biotic stresses is poorly understood compared with that in plant resistance to abiotic stresses. Here, we characterized the function of anthocyanins in protecting fruit from green mold, the major postharvest disease of citrus fruit. Compared with other oranges, ‘Tarocco’ orange, one of the most important blood oranges enriched in anthocyanins, showed reduced susceptibility to the necrotrophic fungus Penicillium digitatum (Pd) which causes citrus postharvest green mold. Pd infection induced the accumulation of anthocyanins in ‘Tarocco’ orange and exogenous treatment of anthocyanins significantly reduced the susceptibility of citrus fruit to Pd. The accumulation of reactive oxygen species (ROS), which was shown to contribute to plant infection of necrotrophic fungal pathogens, in ‘Tarocco’ orange was less than that in other oranges upon Pd infection. ROS content and associated gene expression in citrus fruit upon Pd infection were reduced after exogenous treatment of anthocyanins. Moreover, transcriptome analysis showed that a lot of genes probably participated in plant–pathogen interaction and anthocyanin biosynthesis were noticeably up-regulated in ‘Tarocco’ orange upon Pd infection. These findings highlight the contribution of anthocyanins to fruit disease resistance and provide significant insights into the control of citrus postharvest green mold.