Ethylene promotes carotenoid accumulation in peach pulp after harvest

•Ethylene treatment promoted carotenoid accumulation in postharvest peaches.•Ethylene treatment induced the expression of PpPSY, PpZDS and PpCHYB.•Ethylene promoted PpERF2 and PpNAC17 expression, but inhibited PpMADS1 expression. The effects of exogenous ethylene and ethylene antagonist (1-methylcyclopropene, 1-MCP) on carotenoid metabolism in the flesh of peach fruit after harvest were investigated. The results revealed that ethylene treatment increased the content of total carotenoids together with the major carotenoid compositions including lutein, β-carotene, β-cryptoxanthin and zeaxanthin and thus promoted fruit coloration during storage of peach fruit, whereas 1-MCP treatment had an opposite effect. Moreover, ethylene also accelerated endogenous ethylene production rate and fruit softening in peaches during storage, which was inhibited by 1-MCP treatment. Gene expression analysis showed that the transcript levels of three carotenoid synthetic genes (PpPSY, PpZDS and PpCHYB) and two transcription factors (PpERF2 and PpNAC71) in peach pulp were increased by ethylene treatment and decreased by 1-MCP treatment as compared with the controls, while the expression of PpMADS1 transcription factor exhibited opposite responses to these two treatments. These results suggest ethylene is involved in the regulation of carotenoid accumulation and fruit coloration in postharvest peaches.