Melatonin enhances cold tolerance in drought‐primed wild‐type and abscisic acid‐deficient mutant barley

Abstract

Melatonin is involved in multiple plant developmental processes and various stress responses. To explore the roles of melatonin played as well as its association with abscisic acid (ABA) in a process of drought priming-induced cold tolerance (DPICT), a wild-type barley and its ABA-deficient mutant Az34 counterpart were selected for comparison, in which the effects of melatonin application (either foliarly or rhizospherically) and/or drought priming on the cold tolerance of both types of barleys were systematically investigated. It was demonstrated that the early drought priming induced an increase of endogenous melatonin production, which is not ABA dependent. In addition, exogenously applied melatonin resulted in higher ABA concentration in the drought-primed plants than in the nonprimed plants when exposed to cold stress, indicating that ABA responded in a drought-dependent manner. The interplay of melatonin and ABA leads to plants maintaining better water status. Drought priming-induced melatonin accumulation enhanced the antioxidant capacity in both chloroplasts and mitochondria, which sustained the photosynthetic electron transport in photosynthetic apparatus of the plants under cold stress. These results suggest that the exogenous melatonin application enhances the DPICT by modulating subcellular antioxidant systems and ABA levels in barley.

Physiological response of plants to polyethylene glycol (PEG-6000) by exogenous melatonin application in wheat

“…Exogenous melatonin application resulted in higher ABA concentration in drought-primed plants, suggesting that the interplay between melatonin and ABA improves water status under drought (Li et al, 2016). In this study, leaf ABA content in JM22 under P increased significantly, and decreased under P condition supplemented with 1 μM melatonin and 10 μM melatonin; root ABA content in JM22 under P + 10 μM melatonin was significantly decreased.…”

Melatonin Improves Waterlogging Tolerance of Malus baccata (Linn.) Borkh. Seedlings by Maintaining Aerobic Respiration, Photosynthesis and ROS Migration

“…Melatonin was reported to enhance plant tolerance against various abiotic stressors including cold, hot, drought, salinity, and chemical pollutants (Bajwa et al, 2014; Wei et al, 2014; Liang et al, 2015; Liu et al, 2015; Shi et al, 2015b; Li X. et al, 2016; Xu et al, 2016). But the effect of melatonin on waterlogging resistance is still to be investigated.…”

Exogenous Melatonin Improves Plant Iron Deficiency Tolerance via Increased Accumulation of Polyamine-Mediated Nitric Oxide

“…Although several physiological roles of melatonin in plants have been characterized [5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22], regulation of plant Fe deficiency responses and Fe homeostasis by melatonin have not been reported. The present study provided evidence that exogenous melatonin conferred improved plant adaptation to Fe deficiency by promoting Fe remobilization in Arabidopsis plants.…”

“…It has recently been reported that melatonin can increase the resistance of plants to biotic stress via the salicylic acid (SA)- and nitric oxide (NO)-mediated signaling pathways [14,15]. Furthermore, a large number of publications has documented that melatonin positively participates in the alleviation of plant injury by activating endogenous defense systems against various abiotic stresses, such as UV light, cold, heat, drought, and oxidative stress [16,17,18,19,20,21,22], suggesting that melatonin functions as a novel regulator of abiotic stress responses in plants. However, whether melatonin is involved in the regulation of plant iron (Fe) deficiency responses and the underlying mechanisms are poorly known to date.…”