Short-term anaerobic, pure oxygen and refrigerated storage conditions affect the energy status and selective gene expression in litchi fruit

Harvested litchi fruit were stored under cold temperature, short-term anaerobic and pure oxygen conditions to explore the energy characteristics and the genes that are related to pericarp browning. Fruits in short-term anaerobic and pure oxygen environments were stored at 25°C. Additionally, fruits were stored at 1°C for 1, 2 or 3 weeks and were then subjected to a post cold storage at 25°C for up to 48h. Short-term anaerobic and pure oxygen storage decreased the browning index and relative abundance of the ATP synthase β subunit (LcAtpB) and increased respiration intensity, ATP content, the contribution of an alternate oxidation pathway to the total respiration (ρVAP/Vt) and the transcription of plant uncoupling mitochondria protein 1 (LcUCP1), with short-term anaerobic treatment being more significant than pure oxygen. Cold storage decreased the ATP levels but increased the browning index, respiration intensity, ρVAP/Vt and the transcription of alternative oxidase 1 (LcAOX1), LcUCP1, ADP/ATP carrier 1 (LcAAC1) and sucrose non-fermenting-1-related kinase 2 (LcSnRK2) during the post storage shelf-life at 25°C. The data suggest that the energy level is closely related to the respiratory activity and is involved in the browning control of harvested litchi fruit. Transcripts of the 5 genes were found to be involved in the energy regulation and quality control of postharvest litchi fruit.