Melatonin: A Multifunctional Factor in Plants

Abstract

Melatonin (N-acetyl-5-methoxy-tryptamine) is a universal molecule that is present in animals and plants. It has been detected in different kinds of plants and organs in different levels. Melatonin in plants shares the same initial biosynthesis compound with auxin, and therefore functions as indole-3-acetic acid like hormones. Moreover, melatonin is involved in regulating plant growth and development, protecting plants against biotic and abiotic stresses, such as salt, drought, cold, heat and heavy metal stresses. Melatonin improves the stress tolerance of plants via a direct pathway, which scavenges reactive oxygen species directly, and indirect pathways, such as increasing antioxidate enzymes activity, photosynthetic efficiency and metabolites content. In addition, melatonin plays a role in regulating gene expression, and hence affects performance of plants. In this review, the biosynthesis pathway, growth and development regulation, and the environment stress response of melatonin in plants are summarized and future research directions and priorities of melatonin in plants are speculated.

Melatonin delays leaf senescence of Chinese flowering cabbage by suppressing ABFs‐mediated abscisic acid biosynthesis and chlorophyll degradation

“…Increasing evidence demonstrates that melatonin acts synergistically or antagonistically with other plant hormones including auxin, CTK, GA, ABA, ethylene, and JA during biological processes, mainly in stress responses . Under high salinity stress, melatonin promoted cucumber seed germination by reducing ABA accumulation achieved by downregulating ABA biosynthetic genes and upregulating ABA catabolic genes .…”

“…Increasing evidence demonstrates that melatonin acts synergistically or antagonistically with other plant hormones including auxin, CTK, GA, ABA, ethylene, and JA during biological processes, mainly in stress responses. [4][5][6][44][45][46][47] Under high salinity stress, melatonin promoted cucumber seed germination by reducing ABA accumulation achieved by downregulating ABA biosynthetic genes and upregulating ABA catabolic genes. 48 In drought-stressed apple plants, melatonin treatment selectively downregulated ABA biosynthetic gene MdNCED3 and upregulated ABA catabolic genes such as MdCYP707A1 and MdCYP707A2, thus reducing ABA accumulation.…”

Advances in Characterizing Recently-Identified Molecular Actions of Melatonin: Clinical Implications

“…In this animal model, melatonin reduced CAC-induced autophagy as revealed by the expression pattern of various autophagy markers such as beclin1, LC3B-II/ LC3B-I ratio and p62 [252]. Melatonin also induces the autophagic pathway in tongue squamous cell carcinoma cell line, Cal 27, as evidenced by the upregulation of LC3-II and downregulation of SQSTM1/P62 [61]. Valproic acid (VA) inhibits invasiveness of bladder cancer.…”

“…These functions are not discussed in detail in the current review, but they may be mentioned when they are germane to the discussion. Also, the functions of melatonin in plants [18,61,62,194] are not considered even though…”

Melatonin inhibits peroxide production in plant mitochondria

“…В многочисленных исследованиях было продемонстрировано, что обработка мелатонином растений также способствовала повышению стресстолерантности благодаря, как полагают, его антиоксидантным свойствам [9]. Тем не менее в литературе отсутствуют экспериментальные данные о влиянии данного гормона на метаболическую активность митохондрий растений, включая продукцию АФК.…”