A ménage à trois: salicylic acid, growth inhibition, and immunity

Salicylic acid (SA) is a hormone that accumulates in plants during immunity towards pathogens. A side effect of SA accumulation is a reduction of plant growth that does not arise from SA toxicity. It is performed in a controlled manner, with SA acting as a signaling molecule. Multiple mechanisms are involved in SA-induced growth suppression and include modifying metabolism, interplay with other hormones, and affecting ROS signaling. This involves SA-binding proteins and the reprograming of the transcriptome and the proteome. In growth suppression, SA can act independently of NPR1, a classical SA-binding protein. A better understanding of SA-induced growth suppression is required in order to delineate its functions in immunity and thus develop resistant crops. Salicylic acid (SA) is a plant hormone almost exclusively associated with the promotion of immunity. It is also known that SA has a negative impact on plant growth, yet only limited efforts have been dedicated to explain this facet of SA action. In this review, we focus on SA-related reduced growth and discuss whether it is a regulated process and if the role of SA in immunity imperatively comes with growth suppression. We highlight molecular targets of SA that interfere with growth and describe scenarios where SA can improve plant immunity without a growth penalty. Salicylic acid (SA) is a plant hormone almost exclusively associated with the promotion of immunity. It is also known that SA has a negative impact on plant growth, yet only limited efforts have been dedicated to explain this facet of SA action. In this review, we focus on SA-related reduced growth and discuss whether it is a regulated process and if the role of SA in immunity imperatively comes with growth suppression. We highlight molecular targets of SA that interfere with growth and describe scenarios where SA can improve plant immunity without a growth penalty. an endocytic trafficking pathway implicating vesicles coated in clathrin proteins. It has a regulatory role in many cellular processes, including hormonal signaling. nuclear proteins that function as negative regulators of gibberellin signaling and contain a conserved amino acid motif (DELLA) in their N terminal domains. Perception of gibberellin leads to proteasome-mediated degradation of DELLA proteins and de-repression of growth. an unsaturated hydrocarbon gas acting as a plant hormone and best known for its role in fruit ripening, flower opening, and leaf abscission. enzymes catalyzing the conjugation of the reduced form of glutathione to proteins, thus modifying their properties. a ratio between reduced and oxidized forms of glutathione, which is an indicator of cell redox status and oxidative stress. In the oxidized form (GSSG), two glutathione molecules are bound by a disulfide bridge. In the reduced glutathione form (GSH), such disulfide bridges are cleaved. an inactive SA isomer. the most common auxin class plant hormone serving as a signaling molecule required for growth coordination and the development of plant organs. a transcriptional regulator acting as a master regulator within the plant defense signaling network. mitotic cell division occurring parallel to the tissue or organ surface. a general term for highly reactive chemical molecules formed due to the electron receptivity of O2; includes peroxides, superoxide, hydroxyl radical, and singlet oxygen. (2-hydroxybenzoic acid); a plant hormone involved in plant growth and development and plant defense against pathogens. a protein that directly binds SA. When SABP is an enzyme, this could alter its activity. a process that triggers the resistance of a whole plant following a local infection. The onset of SAR is controlled by different signaling molecules, including a derivative of SA, methylsalicylate. a class of ubiquitous proteins acting in redox signaling. A common mechanism of TRX action is by the reduction of protein disulfide bonds.