The biochemistry, genetics and physiology of ripening have been studied extensively in fruits and a considerable amount of information is available which ranges from the physiological and biochemical changes during ripening to ethylene biosynthesis and the mechanisms of perception, signaling and control of gene expression etc. The major components of the pathway for ethylene signal transduction have been identified by genetic approaches in Arabidopsis and have now been shown to function in agronomically important fruit plants as well. Studies on ethylene signaling in tomato has demonstrated conservation of the basic model defined in Arabidopsis, yet with modifications in gene family composition and expression. In recent years progress has been made on several fronts such as localization of ethylene receptor signaling complex at the endoplasmic reticulum, the regulation of constitutive triple response (CTR) activity by these receptors, the identification of mitogen-activated protein kinase (MAPK) cascade, the characterization and cloning of several ethylene insensitive (EIN) transcription factors from many plant species as well as ethylene response factors (ERF) family of transcription factors. The present review focuses on recent advances on ethylene signal transduction in particular of fruit ripening.
Ethylene, fruit, perception, ripening, signal transduction
