Antofine Triggers the Resistance Against Penicillium italicum in Ponkan Fruit by Driving AsA-GSH Cycle and ROS-Scavenging System

Abstract

Postharvest fungal infection can accelerate the quality deterioration of Ponkan fruit and reduce its commodity value. Penicillium italicum is the causal pathogen of blue mold in harvested citrus fruits, not only causing huge fungal decay but also leading to quality deterioration. In our preliminary study, antofine (ATF) was found to have a great potential for significant in vitro suppression of P. italicum growth. However, the regulatory mechanism underpinning ATF-triggered resistance against P. italicum in citrus fruit remains unclear. Here, the protective effects of ATF treatment on blue mold development in harvested Ponkan fruit involving the enhancement of ROS-scavenging system were investigated. Results showed that ATF treatment delayed blue mold development and peel firmness loss. Moreover, the increase of electrolyte leakage, O2•– production, and malonyldialdehyde accumulation was significantly inhibited by ATF treatment. The ATF-treated Ponkan fruit maintained an elevated antioxidant capacity, as evidenced by inducted the increase in glutathione (GSH) content, delayed the declines of ascorbic acid (AsA) content and GSH/oxidized GSH ratio, and enhanced the activities of superoxide dismutase, catalase, peroxidase, and six key AsA-GSH cycle-related enzymes, along with their encoding gene expressions, thereby maintaining ROS homeostasis and reducing postharvest blue mold in harvested Ponkan fruit. Collectively, the current study revealed a control mechanism based on ATF-triggered resistance and maintenance of a higher redox state by driving AsA-GSH cycle and ROS-scavenging system in P. italicum-infected Ponkan fruit.

Maintenance of postharvest storability and overall quality of ‘Jinshayou’ pummelo fruit by salicylic acid treatment

“…In addition to AsA, GSH is another representative substrate in AsA-GSH system (Halliwell-Asada cycle), both of them perform a pivotal role in the AsA-GSH system together with other enzymatic antioxidant systems to maintain redox homeostasis in postharvest fruits, and their amount can directly indicate the fruits’ ability to scavenge ROS ( Hanaei et al., 2022 ; Peng et al., 2022 ). Figure 4B showed that GSH content in the control and 0.3% SA-treated fruit revealed the similar trend — i.e., a slight increase over the first 30 d of postharvest storage, followed by a gradual decrease.…”

“…SOD, CAT, APX, GR, and POD are pivotal antioxidant enzymes that share their responsibility for scavenging excess ROS, thus protecting plant cells against oxidative stress ( Marschall and Tudzynski, 2016 ; Nie et al., 2020 ; Chen et al., 2022 ). Specially, SOD plays its pioneer role in the ROS-scavenging enzymatic antioxidant system, which can dismutate superoxide anion into O 2 and H 2 O 2 ; subsequently, the disproportionated H 2 O 2 is directly or indirectly decomposed into O 2 and H 2 O 2 with the concerted effort from CAT, APX, GR, and POD ( Siboza et al., 2017 ; Martínez-Camacho et al., 2022 ; Peng et al., 2022 ). Numerous studies have proved that pre-storage SA treatment helps in maintaining or enhancing the antioxidant capacity in harvested fruits through the activation of antioxidant enzymatic system ( Dokhanieh et al., 2013 ; Serna-Escolano et al., 2021 ; Zhang et al., 2021a ).…”

“…In addition to enzymatic antioxidant system, the non-enzymatic antioxidant system also has its irreplaceable role in reducing the oxidative senescence in harvested fruits ( Supapvanich et al., 2017 ; Hanif et al., 2020 ; Nie et al., 2020 ). In higher plants, AsA and GSH are both representative substrates in AsA-GSH system (Halliwell-Asada cycle) for scavenging over-accumulated ROS in fruit, which maintains ROS homeostasis and delays cell senescence caused by oxidative stress ( Serna-Escolano et al., 2021 ; Hanaei et al., 2022 ; Peng et al., 2022 ). Additionally, phenolics compounds are a class of plant secondary metabolites that perform a pivotal role in the color conversion, flavor formation, and stress resistance of harvested fruits, in conjunction with flavonoids, which protect them from the oxidative damage caused by the over-production of ROS ( Ackah et al., 2022 ; Jiang et al., 2022 ).…”

“…The activities of CAT (EC 1.11.1.6), APX (EC 1.11.1.11), and GR (EC 1.8.1.7) were measured as the description of Ackah et al. (2022) and Peng et al. (2022) , and the results were reported as U g -1 FW, where one unit (U) of CAT, APX, and GR activities was defined as an increase in the absorbance by 0.01 per minute at 240 nm, 290 nm, and 340 nm, respectively.…”

Apple polyphenols delay postharvest senescence and quality deterioration of ‘Jinshayou’ pummelo fruit during storage

“…GR (EC 1.8.1.7) activity was determined following the method of Peng et al (2022). 30 mL of nicotinamide adenine dinucleotide phosphate was added to 3.0 mL of 100 mM phosphate buffer (pH 7.5), 0.2 mL of enzyme crude extract, and 0.1 mL of 10 mM oxidized GSH to initiate the reaction mixture (3.3 mL) for GR activity.…”