Salicylic Acid: A Phenolic Molecule with Multiple Roles in Salt-Stressed Plants

Salicylic acid (SA) has multiple functions in plants, either under optimal or environmental stress conditions. In salt-stressed plants, SA in coordination with other plant hormones (e.g., auxins, abscisic acid, gibberellins) and other signaling molecules can take part to the finely tuned regulatory network, to promote the stimulation of plant defenses aimed at counteracting the salt-triggered harmful effects. This review summarizes the most updated literature dealing with the roles of SA in salt-stressed plants with the aim to provide a comprehensive picture about physiological, biochemical and molecular mechanisms mediated by SA during salt stress, to highlight the possible beneficial effect of SA supplementation and to orientate the direction of future research on this topic.