Nitric oxide and hydrogen sulfide share regulatory functions in higher plant events

Nitric oxide (NO) and hydrogen sulfide (HS) are two molecules that share signaling properties in plant and animal cells. NO and HS originate two families of derived molecules designated reactive nitrogen and sulfur species (RNS and RSS, respectively). These molecules are responsible for certain protein regulatory processes through posttranslational modifications (PTMs), being the most remarkable S-nitrosation and persulfidation, which affect the thiol group of cysteine residues. NO and HS can also exert regulatory functions due to their interaction through the iron present in proteins that contain heme groups or iron-sulfur clusters, as reported mainly in animal cells. However, the available information in plant cells is still very limited thus far. In higher plants, NO and HS are involved in a myriad of physiological events from seed germination to fruit ripening, but also the mechanism of response to biotic and abiotic stress conditions. This viewpoint manuscript highlights the functional regulatory parallelism of these two molecules which also interact with the metabolism of reactive oxygen species (ROS) in plant cells.FJC and JMP research is supported by a European Regional Development Fund cofinanced grant from the Spanish Ministry of Science and Innovation (PID2019-103924GB-I00), the Plan Andaluz de Investigación, Desarrollo e Innovación (PAIDI 2020) (P18-FR-1359) and Junta de Andalucía (Group BIO192), Spain