Controlled levels of salicylic acid are required for optimal photosynthesis and redox homeostasis

• Published in: Journal of experimental botany Vol. 57; no. 8; pp. 1795 - 1807
• Main Authors: Mateo, Alfonso, Funck, Dietmar, Mühlenbock, Per, Kular, Baldeep, Mullineaux, Philip M, Karpinski, Stanislaw
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.01.2006; Oxford Publishing Limited (England)
• Subjects: acclimation; Acclimatization; Acclimatization - physiology; antioxidants; Antioxidants - metabolism; Arabidopsis; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis cross tolerance defence reactions glutathione hydrogen peroxide light acclimation photo-oxidative stress photosynthesis redox signalling salicylic acid; Arabidopsis thaliana; Biologi; Biology; Biomass; Carbon Dioxide - metabolism; Catalase - metabolism; cross tolerance; defence reactions; gene expression; Gene expression regulation; glutathione; Glutathione - metabolism; Glutathione Reductase - metabolism; homeostasis; Homeostasis - physiology; hydrogen peroxide; Leaves; Light; light acclimation; light intensity; light stress; NATURAL SCIENCES; NATURVETENSKAP; Organism biology; Organismbiologi; Oxidation-Reduction; Oxidative stress; Pathogens; photo-oxidative stress; Photosynthesis; Photosynthesis - physiology; Plant cells; Plant Leaves - metabolism; Plant physiology; Plants; Reactive oxygen species; Reactive Oxygen Species - metabolism; redox potential; redox signalling; salicylic acid; Salicylic Acid - metabolism; Starch - metabolism; Superoxide Dismutase - metabolism; Växtfysiologi
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/erj196

Sudden exposure of plants to high light (HL) leads to metabolic and physiological disruption of the photosynthetic cells. Changes in ROS content, adjustment of photosynthetic processes and the antioxidant pools and, ultimately, gene induction are essential components for a successful acclimation to the new light conditions. The influence of salicylic acid (SA) on plant growth, short-term acclimation to HL, and on the redox homeostasis of Arabidopsis thaliana leaves was assessed here. The dwarf phenotype displayed by mutants with high SA content (cpr1-1, cpr5-1, cpr6-1, and dnd1-1) was less pronounced when these plants were grown in HL, suggesting that the inhibitory effect of SA on growth was partly overcome at higher light intensities. Moreover, higher SA content affected energy conversion processes in low light, but did not impair short-term acclimation to HL. On the other hand, mutants with low foliar SA content (NahG and sid2-2) were impaired in acclimation to transient exposure to HL and thus predisposed to oxidative stress. Low and high SA levels were strictly correlated to a lower and higher foliar H2O2 content, respectively. Furthermore high SA was also associated with higher GSH contents, suggesting a tight correlation between SA, H2O2 and GSH contents in plants. These observations implied an essential role of SA in the acclimation processes and in regulating the redox homeostasis of the cell. Implications for the role of SA in pathogen defence signalling are also discussed.