Hydrogen sulfide alleviates chilling injury by modulating respiration and energy metabolisms in cold-stored peach fruit

Abstract

The respiration and energy metabolisms of refrigerated peach fruit and their relationship to chilling injury (CI) treated with hydrogen sulfide (H2S) were investigated. Results showed that H2S treatment reduced the activities of hexokinase (HK), phosphor-glucose isomerase (PGI), phosphofructokinase (PFK) and pyruvate kinase (PK), and the contents of glucose, pyruvate and nicotinamide adenine dinucleotide (hydrogen) (NAD(H)) in the Embden-Meyerhof-Parnas (EMP) and tricarboxylic acid (TCA)-cycle compared to control and hypotaurine (HT, H2S scavenger) treatment, resulting in a lower respiration rate. Meanwhile, H2S treatment increased the activities of NADK, glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) and NADP(H) contents in the pentose phosphate pathway (PPP), while HT showed the opposite results. Moreover, H2S treatment induced the higher activities of adenosine triphosphatases (ATPases), succinic dehydrogenase (SDH) and cytochrome C oxidase (CCO) along with enhanced levels of ATP and energy charge, whereas HT suppressed energy generation, which increased cell membrane permeability and malondialdehyde content. Therefore, results suggested that H2S could maintain the integrity of the membrane structure by inhibiting the respiration and substance consumption in EMP pathway, increasing the proportion of PPP and energy supply to alleviate CI in peaches.