Crosstalk between Hydrogen Sulfide and Other Signal Molecules Regulates Plant Growth and Development

Hydrogen sulfide (H₂S), once recognized only as a poisonous gas, is now considered the third endogenous gaseous transmitter, along with nitric oxide (NO) and carbon monoxide (CO). Multiple lines of emerging evidence suggest that H₂S plays positive roles in plant growth and development when at appropriate concentrations, including seed germination, root development, photosynthesis, stomatal movement, and organ abscission under both normal and stress conditions. H₂S influences these processes by altering gene expression and enzyme activities, as well as regulating the contents of some secondary metabolites. In its regulatory roles, H₂S always interacts with either plant hormones, other gasotransmitters, or ionic signals, such as abscisic acid (ABA), ethylene, auxin, CO, NO, and Ca²⁺. Remarkably, H₂S also contributes to the post-translational modification of proteins to affect protein activities, structures, and sub-cellular localization. Here, we review the functions of H₂S at different stages of plant development, focusing on the S-sulfhydration of proteins mediated by H₂S and the crosstalk between H₂S and other signaling molecules.