The Molecular Regulation of Ethylene in Fruit Ripening

Fleshy fruits are major sources of necessary nutrients in many diets worldwide. Most fruit quality attributes emerge during ripening making the fruit more attractive to consumers. Understanding the molecular regulatory network underpinning fleshy fruit ripening is important not only for fruit quality improvement but also for postharvest shelf life. The phytohormone ethylene plays an essential role in climacteric fruit ripening and a number of studies have demonstrated that ethylene signaling components and related transcription factors are involved in the regulation of fruit ripening. However, the transcriptional network by which ethylene interacts with other signaling pathways to regulate the ripening process is not fully understood. In this review, focusing on the tomato as a reference species, the key points regarding the role of ethylene in coordinating the ripening process at the molecular and physiological levels are described. The interplay between ethylene and ripening-related regulators and its crosstalk with other phytohormones and present recent data on ripening-related epigenetic modifications are also discussed. Overall, the paper summarizes the most advanced research progress in this area to help facilitate its future development.