Nitric oxide and hydrogen sulfide in higher plants under physiological and stress conditions

Nitric oxide (NO) and hydrogen sulfide (H2S) are two gasotransmitters endogenously generated in plant cells. Each belongs to a family of related molecules called reactive nitrogen and sulfur species (RNS and RSS), respectively, which perform multiple functions in the physiology of plants. NO and H2S appear to share various plant tasks and are involved in a wide range of physiological processes, including seed germination, root architecture, plant growth and development, stomatal movement, senescence and fruit ripening, as well as in the mechanism of response to environmental stresses [1,2,3,4]. Their mechanism of action is mainly through protein posttranslational modifications, such as S-nitrosation, nitration and persulfidation, which affect the redox status and function of target proteins [5,6,7]. NO and H2S, which mediate several signaling networks, are key elements in the biochemistry and physiology of plants. Furthermore, increasing experimental data demonstrate crosstalk between these molecules and reactive oxygen species (ROS) metabolism. However, information on the plant cell metabolism of NO and H2S is still limited compared to that on ROS metabolism. A simple search in the PubMed database using the terms plant and the corresponding reactive species enables one to access all of the relevant information published in this field, wherein RNS and RSS account for only 23% and 1% of the total, as compared to 76% for ROS (Figure 1).F.J.C. research work is supported by the ERDF-cofinanced grant from the Ministry of Economy and Competitiveness (AGL2015-65104-P) and Junta de Andalucía (group BIO192), Spain.Peer reviewe