Regulation of water, salinity, and cold stress responses by salicylic acid

Abstract

Salicylic acid (SA) is a naturally occurring phenolic compound. SA plays an important role in the regulation of plant growth, development, ripening, and defense responses. The role of SA in the plant–pathogen relationship has been extensively investigated. In addition to defense responses, SA plays an important role in the response to abiotic stresses, including drought, low temperature, and salinity stresses. It has been suggested that SA has great agronomic potential to improve the stress tolerance of agriculturally important crops. However, the utility of SA is dependent on the concentration of the applied SA, the mode of application, and the state of the plants (e.g., developmental stage and acclimation). Generally, low concentrations of applied SA alleviate the sensitivity to abiotic stresses, and high concentrations of applied induce high levels of oxidative stress, leading to a decreased tolerance to abiotic stresses. In this article, the effects of SA on the water stress responses and regulation of stomatal closure are reviewed.

Exogenous salicylic acid improves photosynthesis and growth through increase in ascorbate-glutathione metabolism and S assimilation in mustard under salt stress

“…Application of SA has been shown to influence plant growth by promoting protective reactions involving photosynthetic pigments and membrane integrity. 26,27 Of the strategies capable of counteracting salt stress and its detoxification, the pivotal role of AsA-GSH pools and the coordination between AsA-GSH regenerating enzymes with other enzymatic antioxidants should be studied. Activities of enzymes in the ascorbate glutathione cycle are increased under salt stress suggesting a requirement for increased activity of the cycle under these conditions.…”

Cold hardening protects cereals from oxidative stress and necrotrophic fungal pathogenesis

“…Notably, cold acclimation in plants is a potent inducer of salicylic acid and ethylene accumulation [47][48][49][50], transcription factors [40], calcium signaling [51,52], pathogenesis-related and antifungal proteins [5] along with anatomical changes, and cell membrane or cytoskeleton restructuring [53]. Consequently, besides plant antioxidative systems several other host factors should be considered as potential mechanisms behind the observed resistance response in cold hardened barley challenged by infection with P. teres f. teres.…”

Plant strategies to deal with a combination of drought and high temperatures

“…However, recent studies have suggested that SA also plays an important Chapter 1 36 role in abiotic stress-induced signaling and tolerance [11,18]. Particularly, it has been proposed that SA may induce thermotolerance in several plant species [19][20][21][22] …”

“…Plant responses to external stimuli are mainly mediated by phytohormones, whose involvement in abiotic stress responses has been deeply studied [9][10][11][12]. Under drought or high salinity, abscisic acid (ABA) seems to be an important stress-signaling hormone [13,14], involved in the regulation of stomatal closure, synthesis of compatible osmolytes and up-regulation of genes leading to adaptive responses.…”

“…In addition to defense responses, SA plays an important role in the response to abiotic stresses [11] and especially in the tolerance to high temperatures [19][20][21][22]52]. Moreover, previous studies indicate that SA-signaling pathways involved in SAR overlap with those promoting basal thermotolerance since mutations known to affect SA-signaling in pathogen defenses also affect heat tolerance [21].…”