Melatonin-Induced Water Stress Tolerance in Plants: Recent Advances

Abstract

Water stress (drought and waterlogging) is severe abiotic stress to plant growth and development. Melatonin, a bioactive plant hormone, has been widely tested in drought situations in diverse plant species, while few studies on the role of melatonin in waterlogging stress conditions have been published. In the current review, we analyze the biostimulatory functions of melatonin on plants under both drought and waterlogging stresses. Melatonin controls the levels of reactive oxygen and nitrogen species and positively changes the molecular defense to improve plant tolerance against water stress. Moreover, the crosstalk of melatonin and other phytohormones is a key element of plant survival under drought stress, while this relationship needs further investigation under waterlogging stress. In this review, we draw the complete story of water stress on both sides—drought and waterlogging—through discussing the previous critical studies under both conditions. Moreover, we suggest several research directions, especially for waterlogging, which remains a big and vague piece of the melatonin and water stress puzzle.

Mechanisms of Waterlogging Tolerance in Plants: Research Progress and Prospects

“…The MT has been previously reported for its mitigatory role of numerous abiotic stresses ( Sharif et al, 2018 ). Owing to that, research related to MT and its involvement in improving waterlogging stress tolerance is relatively less, and only few research articles are available ( Moustafa-Farag et al, 2020 ).…”

Mechanistic insights on melatonin‐mediated drought stress mitigation in plants

“…Drought stress in plants can lead to the disruption of the membrane system, which ultimately imbalances the redox homeostasis and thus alters physiological and biochemical processes (Sattar et al, 2020). Melatonin was reported to alter physiological, biochemical, and molecular processes to withstand and tolerate stress conditions (Moustafa‐Farag et al, 2020). Various physiological processes such as photosynthesis, stomatal conductance, root dynamics, water relation, and carbohydrate assimilation may be modulated to overcome stress conditions (Sharma & Zheng, 2019).…”

Melatonin as a regulatory hub of plant hormone levels and action in stress situations

“…One of the most studied actions of melatonin is its role as a biostimulant in both biotic and abiotic stress situations (Banerjee & Roychoudhury 2017; Moustafa‐Farag et al 2020a,b). Melatonin acts chemically by scavenging several reactive oxygen species (ROS) and reactive nitrogen species (RNS) such as O 2 · , ·OH ‐ , NO.…”