Melatonin, an animal hormone acting as endogenous synchronizer for physiological rhythms, was discovered in plants in 1995. This review presents some aspects of the relationship between melatonin and the plant hormones auxin, cytokinin, gibberellins, abscisic acid, ethylene, jasmonic acid and salicylic.
Arnao and Hernández-Ruiz discuss the effects some melatonin treatments have on endogenous plant hormone levels, their related genes (biosynthesis, catabolism, receptors and transcription factors), and the physiological actions induced by melatonin, mainly in stress conditions. The data present melatonin as a relevant modulator of gene expression related to plant hormones. The identification of a possible melatonin receptor in plants is a priority task to elucidate the action mechanism that activates the responses of melatonin in plants.