Updated project metadata. Hydrogen sulfide is an important signaling molecule in plants that regulates essential biological processes through protein persulfidation. Although numerous persulfidated proteins were found to be involved in photorespiration, little was known about sulfide-mediated regulation of photorespiration. Label-free quantitative proteomic analysis has revealed a high impact on the protein persulfidation level when plants grown under non-photorespiratory conditions are transferred to air, with the 97 % of total identified proteins more persulfidated under suppressed photorespiration. A detailed study of the effect of sulfide on important aspects associated with photorespiratory growth conditions has provided insight into the role of sulfide in protecting plants grown under suppressed photorespiration. In these conditions, sulfide amends the metabolic imbalance of carbon/nitrogen and restores ATP levels to concentrations similar to those in air grown conditions. Sulfide also plays an essential role in balancing the significant high level of ROS measured in plants under non-photorespiratory conditions to reach a similar cellular redox state in air-grown plants, through the regulation of antioxidative defenses. Furthermore, sulfide regulates another important characteristic resulting from suppression of photorespiration, such as the stomata closure, to decrease the high guard cell ROS levels and inducing the stomata aperture. In this way, sulfide signals the movement of the CO2-dependent stomata to achieve a scenario similar to that of plants growing under normal air conditions, in the opposite direction of the already established ABA-dependent movement of the stomata. Therefore, our findings suggest that the high persulfidation level under suppressed photorespiration reveals an essential role of sulfide signaling under these conditions, and with respect to stomatal movement, the outcome of this signaling is dependent on the growth/stress condition under study.