Ethylene Signaling during Leaf Senescence

Abstract

Leaf senescence is a degradation phenomenon which is genetically controlled and regulated by different plant hormones, signaling molecules, and transcription factors. Ethylene, a gaseous hormone, not only affects many processes important for plant growth and development, but also helps plants to mitigate various biotic and abiotic stresses. Senescence is a quite discernable part in the life cycle of plants. Its onset commences with the chlorophyll loss in the cells and finally to the degradation of macromolecules paving the way to the survival of plants by preserving the nutrients. Ethylene together with other phytohormones plays a vital role in integrating different signals and allowing the onset of favorable conditions for plant development, reproduction, and senescence. The ethylene-regulated processes in plants including senescence are commenced by ethylene biosynthesis controlled by a complex signaling network. Ethylene is then perceived by specific ethylene receptors present in neighboring cells. These signals are thereafter transduced and expressed in the form of various cellular responses. This chapter summarizes the detailed overview of the ethylene biosynthesis, signal perception, signal transduction, and role of ethylene in the onset of leaf senescence, a network of ethylene cross-talks with other plant hormones, and its role in abiotic stress management.