Strigolactones Stimulate High Light Stress Adaptation by Modulating Photosynthesis Rate in Arabidopsis

Strigolactones (SLs), a class of carotenoid-derived phytohormones, were originally discovered as rhizosphere signaling molecules. They stimulate parasitic plant seed germination and can establish a symbiotic relationship between plants and beneficial microbes. In addition to their plant developmental role, evidence for their role in various stress responses such as salt and drought stresses was reported recently. In the present study, we tried to understand the unique metabolic pathways that were regulated by SLs in comparison with other plant hormones. We identified that SLs were predominantly modulating photosynthetic pathways in comparison with other plant hormones. Further, we observed that SLs positively influence high light tolerance, and this process is dependent on SL-mediated photosynthesis rate regulation. In addition, the dynamic changes of the metabolites involved in glycolysis and tricarboxylic acid (TCA) cycle upon external application of SL analogue suggest the stress adaptation landscape of plants. Our study presents the dynamic and specific effect of SLs in high light-driven stress adaptation through photosynthesis in plants.