Plant hormone ethylene regulates a wide range of physiological processes during plant development and coordinates plant responses to stresses. Ethylene controls important characteristics of agricultural crops such as the fruit ripening rate and plant resistance to adverse conditions. Understanding the molecular mechanisms of ethylene’s action is one of the actual questions in both the fundamental and applied contexts. Ethylene biosynthesis from methionine and the main steps of the transduction of the ethylene signal from membrane receptors to effector genes have been studied in detail and widely discussed in many reviews. At the same time, the genetic regulation of these two processes has been poorly studied, although it is responsible for the rapid and accurate reaction of plants to various endogenous and external stimuli and for the diversity of the physiological responses of plants to ethylene. This review summarizes the information about the regulatory mechanisms of ethylene biosynthesis and signal transduction. The key factors of transcriptional and post-translational regulation, which control the expression and stability of the main components of the biosynthesis and signaling pathways of ethylene, and the multiple feedbacks supplementing the linear model of ethylene’s signaling pathway are described. Special attention is paid to the role of the ethylene crosstalk with other plant hormones. Different mechanisms of hormonal interaction are illustrated by examples of the synergy or antagonism between ethylene and auxin, jasmonates, cytokinins, and brassinosteroids. The possible molecular bases of the diversity of the physiological responses to ethylene are also discussed.
- plant hormones
- post-translational regulation
- signal transduction pathway
- transcriptional regulation