Melatonin enhances salt tolerance by promoting MYB108A-mediated ethylene biosynthesis in grapevines

Abstract

The signal molecules melatonin and ethylene play key roles in abiotic stress tolerance. The interplay between melatonin and ethylene in regulating salt tolerance and the underlying molecular mechanism of this interplay remain unclear. Here, we found that both melatonin and 1-aminocyclopropane-1-carboxylic acid (ACC, a precursor of ethylene) enhanced the tolerance of grapevine to NaCl; additionally, ethylene participated in melatonin-induced salt tolerance. Further experiments indicated that exogenous treatment and endogenous induction of melatonin increased the ACC content and ethylene production in grapevine and tobacco plants, respectively. The expression of MYB108A and ACS1, which function as a transcription factor and a key gene involved in ethylene production, respectively, was strongly induced by melatonin treatment. Additionally, MYB108A directly bound to the promoter of ACS1 and activated its transcription. MYB108A expression promoted ACC synthesis and ethylene production by activating ACS1 expression in response to melatonin treatment. The suppression of MYB108A expression partially limited the effect of melatonin on the induction of ethylene production and reduced melatonin-induced salt tolerance. Collectively, melatonin promotes ethylene biosynthesis and salt tolerance through the regulation of ACS1 by MYB108A.

Ethylene: A Master Regulator of Salinity Stress Tolerance in Plants

“…Moreover, ethylene has also been found as an essential positive mediator of salinity stress tolerance in grapevine [13], maize [12], and tomato [48]. Promising evidence of the involvement of melatonin in enhancing salinity stress tolerance by promoting MYB108A-mediated ethylene biosynthesis was also reported in grapevines [13]. It has been reported that inhibition of ethylene biosynthesis and/or signaling leads to increased sensitivity of plants to salinity stress.…”

“…Overproduction of endogenous ethylene or exogenous treatment of ethylene-releasing compounds such as ethephon or ethylene precursors such as 1-aminocyclopropane-1-carboxylic acid (ACC) increase salinity stress tolerance in various plants including Arabidopsis [47] and maize [12]. Moreover, ethylene has also been found as an essential positive mediator of salinity stress tolerance in grapevine [13], maize [12], and tomato [48]. Promising evidence of the involvement of melatonin in enhancing salinity stress tolerance by promoting MYB108A-mediated ethylene biosynthesis was also reported in grapevines [13].…”

“…In addition to regulating plant growth and development, research in the past two decades has also highlighted the involvement of ethylene in regulating plant responses to various biotic and abiotic stresses [6][7][8][9]. Among different abiotic stresses, ethylene has emerged as one of the important positive mediators for salinity stress tolerance in the model plant A. thaliana as well as in many crop plants including grapevines, maize, and tomato [10][11][12][13]. Salinity stress is one of the major abiotic stresses, posing a major threat to agricultural productivity [14,15].…”

Melatonin Application Improves Salt Tolerance of Alfalfa (Medicago sativa L.) by Enhancing Antioxidant Capacity

“…The crosstalk of melatonin with other phytohormones occurs through regulating the expression of its upstream and downstream genes. Melatonin modulates the salt tolerance of grapevines by enhancing ethylene biosynthesis via regulating the transcripts of ACS1 [44]. Melatonin regulates the salt tolerance of sunflower by accompanying with NO to modulate the expression of Cu/Zn-SOD and Mn-SOD genes [45].…”

Resveratrol Alleviates the KCl Salinity Stress of Malus hupenensis Rhed. Seedlings by Regulating K+/Na+ Homeostasis, Osmotic Adjustment, and Reactive Oxygen Species Scavenging

“…The third category contains substances that increase the antioxidant capacity of plants, such as NO, silicon, and melatonin [37,38,39]. Exogenous melatonin can eliminate ROS and enhance the NaCl stress resistance in horticultural crops such as grapes, apple, and cucumber [40,41]. However, most studies focused on NaCl stress; reports on substances that are effective against KCl stress are rare.…”