Influence of hydrogen peroxide on the ROS metabolism and its relationship to pulp breakdown of fresh longan during storage

Graphical abstract
Highlights • H2O2 down-regulated expression of ROS scavenging-related genes in longan pulp. • H2O2 reduced activities of ROS scavenging enzymes (SOD, CAT, APX) in longan pulp. • H2O2 reduced ROS scavenging capacity and raised O2–. generation rate in longan pulp. • H2O2 promoted lipid peroxidation of cell membrane in pulp of harvested longan fruit. • H2O2-reduced ROS scavenging capacity led to H2O2-stimulated pulp breakdown of longans.
The influence of hydrogen peroxide (H2O2) on the ROS metabolism and its relationship to pulp breakdown of fresh longan cv. Fuyan during storage was evaluated. Contrasted to control fruit, H2O2-treated samples manifested a higher index of pulp breakdown, an enhanced rate of O2–. generation, and an increased amount of MDA, but lower APX, CAT and SOD activities, reduced expressions of DlAPX, DlCAT and DlSOD, and lower concentrations of total phenolics, flavonoid, AsA, and GSH as well as lower levels of free radicals scavenging capacity. These data revealed that H2O2-induced pulp breakdown of longan was because H2O2 reduced ability of removing ROS but increased ROS generation and accumulation, which promoted peroxidation of cell membrane lipid, and subsequently led to damaging cell membrane structure and breakdown occurrence in pulp of postharvest fresh longan.