Induction of defense response against Alternaria rot in Zaosu pear fruit by exogenous L-lysine through regulating ROS metabolism and activating defense-related proteins

• Published in: Postharvest biology and technology 2021-09, Vol.179, p.111567, Article 111567
• Main Authors: Liu, Yongxiang, Li, Yongcai, Bi, Yang, Jiang, Qianqian, Mao, Renyan, Liu, Zhitian, Huang, Yi, Zhang, Miao, Prusky, Dov B.
• Format: Article
• Language: English
• Subjects: Alternaria; Alternaria alternata; Amino acids; Catalase; Chitinase; Disease resistance; Fruit rot; Fruits; Gene expression; Hydrogen peroxide; Induce disease resistance; L-lysine; Lysine; Malondialdehyde; Metabolism; Microorganisms; Pear fruit; Peroxidase; Plant immunity; Proteins; Reactive oxygen species; Reactive oxygen species (ROS); Superoxide dismutase
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2021.111567

•Postharvest L-lysine treatment can induce resistance against Alternaria rot in pear fruit.•Postharvest L-lysine treatment can reduce the accumulation of reactive oxygen species.•Postharvest L-lysine treatment increases the accumulation of host pathogenesis-related proteins. L-lysine, an important basic amino acid, its catabolic pathway is activated upon microbial pathogen attack in plants and has a central role in plant immunity. The control effects of exogenous L-lysine treatment on Alternaria rot in postharvest ‘Zaosu’ pear fruit and possible mechanisms involved were studied. The results showed that L-lysine treatment inhibited Alternaria rot development and the effect was negatively correlated with the treatment concentration, lesion diameter of 0.1 mM L-lysine treated fruit was 43.7 % lower than that of the control 15 d after treatment. Further studies showed that L-lysine treatment significantly suppressed O2−, H2O2, Malondialdehyde (MDA) content, and enhanced catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities and gene expression in pear fruit. β-1,3-glucanase (GLU), and chitinase (CHI) activities and PbrGLU, PbrCHI, and PbrPR-1 gene expression were also induced by exogenous L-lysine. The findings suggest that postharvest L-lysine treatment effectively enhanced disease resistance through inhibiting reactive oxygen species (ROS) production and activating defense-related protein in pear fruit.