Melatonin in plant morphogenesis

Abstract

Melatonin is a ubiquitously present indoleamine with a vast capacity for modulating the growth and behavior of plants, animals, and microbes. Though melatonin was discovered in plants decades after its discovery in mammals, its presence has now been confirmed in almost all plant families. Despite this, the in vitro and in vivo mechanisms of action of melatonin are still poorly defined. Although there are an increasingly large number of investigations into the roles of melatonin in plants, few take advantage of in vitro culture systems. Melatonin has been found to possess several important roles in plant growth and development, including functions in rhythmic and cyclic processes, such as chronoregulation, seasonal and senescence processes, as well as modulation of reproductive development, control of root and shoot organogenesis, maintenance of plant tissues, and responses to biotic and abiotic stresses. This review highlights the potential for use of melatonin in several in vitro systems, the roles it plays in plant morphogenesis, and the importance of melatonin in communication within and between plants, and how in vitro systems can be exploited to better understand these understudied functions of melatonin.