BTH Treatment Delays the Senescence of Postharvest Pitaya Fruit in Relation to Enhancing Antioxidant System and Phenylpropanoid Pathway

• Main Authors: Xiaochun Ding, Xiaoyang Zhu, Wang Zheng, Fengjun Li, Shuangling Xiao, Xuewu Duan
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Foods
• Subjects: pitaya; BTH; ROS metabolism; phenylpropanoid pathway
• Online Access: https://www.mdpi.com/2304-8158/10/4/846

The plant resistance elicitor Benzo (1, 2, 3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) can enhance disease resistance of harvested fruit. Nonetheless, it is still unknown whether BTH plays a role in regulating fruit senescence. In this study, exogenous BTH treatment efficiently delayed the senescence of postharvest pitaya fruit with lower lipid peroxidation level. Furthermore, BTH-treated fruit exhibited lower hydrogen peroxide (H₂O₂) content, higher contents of reduced ascorbic acid (AsA) and reduced glutathione (GSH) levels and higher ratios of reduced to oxidized glutathione (GSH/GSSG) and ascorbic acid (AsA/DHA), as well as higher activities of ROS scavenging enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and glutathione reductase (GR) in comparison with control fruit. Moreover, BTH treatment enhanced the activities of phenylpropanoid pathway-related enzymes, including cinnamate-4-hydroxylase (C4H), phenylalanine ammonia-lyase (PAL) and 4-coumarate/coenzyme A ligase (4CL) and the levels of phenolics, flavonoids and lignin. In addition, BTH treatment upregulated the expression of <i>HuSOD1/3/4</i>, <i>HuCAT2</i>, <i>HuAPX1/2</i> and <i>HuPOD1/2/4</i> genes. These results suggested that application of BTH delayed the senescence of harvested pitaya fruit in relation to enhanced antioxidant system and phenylpropanoid pathway.