Hydrogen sulfide in horticulture: Emerging roles in the era of climate change

Future climate change will present many plants with environmental challenges, including extreme temperatures and drought. Hydrogen sulfide (H₂S) has emerged as an important signal transmitting molecule in plants, especially important in many stress responses and it is known to regulate numerous physiological and developmental processes. Being recently suggested as a signaling molecule, research exploring the regulatory functions is continuously progressing regarding the role of H₂S in plant science, agriculture and horticulture. Biosynthesis of H₂S occurs in different cellular compartments from where it can freely translocate via membranes to where needed or be excluded where not required. H₂S interacts with related signaling molecules which together mediate stress tolerance against a plethora of harsh conditions. The H₂S induced tolerance against stresses occurs via regulation of antioxidants activities, endogenous levels of GSH, osmoregulator accumulation, cell signaling proteins, and stress-related gene expression. Overall this efficiently eliminates excessive reactive oxygen species (ROS) and maintains the intracellular redox balance. The current review summarizes the recent progress on H₂S or H₂S donor-mediated abiotic stress tolerance with special reference to climate change and horticulture crops, pre- and post-harvest. Elucidating the role of H₂S in cell signaling pathways may open new horizons towards understanding how exogenous treatments with H₂S in horticulture plants may aid in the tolerance to stress, especially as environmental conditions change, and can secure better crop yields and avoid post-harvest losses.