My research activity started in 1987, I have been able to do both national (the University of Granada and CSIC) and international (Arizona State University in the USA and Kindai University, Japan) centers. My scientific aims have focused on two main biochemical areas: the metabolism of reactive oxygen and nitrogen species (ROS and RNS). Both are interrelated and involved in all the processes of the physiology of plants from germination, development, senescence, fruit ripening, or responses to environmental stresses. These aims have been carried out mainly by studying the function of enzymatic antioxidant systems (catalase, superoxide dismutase, ascorbate glutathione cycle, etc.) as well as enzymes involved in the regulation of cellular redox state (NADPH-generating enzymes) or subcellular compartmental analysis of these systems as a mechanism of regulation, with special attention to an oxidative organelle such as the peroxisome. In this sense, I would like to emphasize that in the field of plant peroxisomes, several works with an eminent biochemical base have been pioneers in the identification and characterization of proteases, NADP dehydrogenases, superoxide dismutases, enzymes of the ascorbate-glutathione cycle (ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase) and especially the identification of the free radical nitric oxide (NO) and more recently hydrogen sulfide (H2S). During the last 25 years, my work has contributed to demonstrating that the endogenous NO is involved in the development, senescence, and response to diverse environmental stresses both abiotic (salinity, heavy metals, extreme temperature, etc.) and biotic. More recently, my work has deepened the post-translational modifications mediated by NO such as tyrosine nitration and S-nitrosation that specifically regulate the function of target proteins identified by proteomics approaches and using mass spectrometry techniques to identify the target residues. On the other hand, through the use of next-generation sequencing (NGS) technologies such as RNAseq or iTraq, I have shown that the S-nitrosoglutathione (GSNO) and NO gas differentially regulate the expression of genes and proteins between different plant organs, particularly fruits, indicating that it is a signaling molecule. These general objectives have been developed in various plant species that include both plants of agronomic interest as model plants such as pepper, pea, olive, rice, sunflower, cucumber, cotton, tomato, wheat, and Arabidopsis thaliana among others, and based on projects of research funded by Spanish and foreign institutions.