Hydrogen sulfide inhibits the browning of fresh-cut apple by regulating the antioxidant, energy and lipid metabolism

Surface browning is the primary limiting factor for the shelf-life of fresh-cut apple. Hydrogen sulfide (H2S) treatment is known to effectively inhibit the browning, however, little is known about the underlying molecular mechanism. In the present paper RNA-Seq technology was used to analyse the transcript expression profiles of control and H2S treated fresh-cut apple immediately after treatment (C0 and S0) and 6 d of storage (C6 and S6) at 4 °C. The results identified 3782 and 1164 differentially expressed unigenes (DEGs) in S0 vs. C0 and S6 vs. C6, respectively. Expression of most DEGs related to antioxidant systems and energy metabolism was up-regulated after H2S treatment, whilst expression of genes encoding polyphenol oxidase, peroxidase, lipid-degrading enzymes, such as lipoxygenase and phospholipase D, was repressed. Further quantitative real-time PCR testing validated the reliability of our RNA-Seq results. We therefore propose that H2S treatment inhibited the surface browning of fresh-cut apple by regulating antioxidant, energy and lipid metabolism to maintain the membrane integrity of the plant tissue.