S-nitrosoglutathione reductase (GSNOR) exerts crucial roles in the homeostasis of nitric oxide (NO) and reactive nitrogen species (RNS) in plant cells through indirect control of S-nitrosation, an important protein post-translational modification in signaling pathways of NO. Using cultivated and wild tomato species, we studied GSNOR function in interactions of key enzymes of reactive oxygen species (ROS) metabolism with RNS mediated by protein S-nitrosation during tomato root growth and responses to salinity and cadmium. Application of a GSNOR inhibitor N6022 increased both NO and S-nitrosothiol levels and stimulated root growth in both genotypes. Moreover, N6022 treatment, as well as S-nitrosoglutathione (GSNO) application, caused intensive S-nitrosation of important enzymes of ROS metabolism, NADPH oxidase (NADPHox) and ascorbate peroxidase (APX). Under abiotic stress, activities of APX and NADPHox were modulated by S-nitrosation. Increased production of H2O2 and subsequent oxidative stress were observed in wild Solanumhabrochaites, together with increased GSNOR activity and reduced S-nitrosothiols. An opposite effect occurred in cultivated S. lycopersicum, where reduced GSNOR activity and intensive S-nitrosation resulted in reduced ROS levels by abiotic stress. These data suggest stress-triggered disruption of ROS homeostasis, mediated by modulation of RNS and S-nitrosation of NADPHox and APX, underlies tomato root growth inhibition by salinity and cadmium stress.

• Keywords
• S-nitrosation, S-nitrosoglutathione reductase, Solanum habrochaites, Solanum lycopersicum, abiotic stress, cadmium, nitric oxide, reactive oxygen species, root growth, salinity,
• MeSH
• Aldehyde Oxidoreductases metabolism   MeSH
• Ascorbate Peroxidases metabolism   MeSH
• Benzamides chemistry   metabolism   pharmacology   MeSH
• Sodium Chloride pharmacology   MeSH
• Stress, Physiological MeSH
• Cadmium toxicity   MeSH
• Plant Roots drug effects   growth & development   metabolism   MeSH
• NADPH Oxidases metabolism   MeSH
• Nitrosation MeSH
• Nitric Oxide metabolism   MeSH
• Oxidative Stress drug effects   MeSH
• Hydrogen Peroxide metabolism   MeSH
• Pyrroles chemistry   metabolism   pharmacology   MeSH
• Reactive Nitrogen Species chemistry   metabolism   MeSH
• Reactive Oxygen Species chemistry   metabolism   MeSH
• Gene Expression Regulation, Plant drug effects   MeSH
• Plant Proteins metabolism   MeSH
• S-Nitrosoglutathione pharmacology   MeSH
• S-Nitrosothiols metabolism   MeSH
• Solanum lycopersicum drug effects   growth & development   metabolism   MeSH
• Solanum growth & development   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Aldehyde Oxidoreductases MeSH
• Ascorbate Peroxidases MeSH
• Benzamides MeSH
• Sodium Chloride MeSH
• formaldehyde dehydrogenase, glutathione-independent MeSH Browser
• Cadmium MeSH
• N6022 MeSH Browser
• NADPH Oxidases MeSH
• Nitric Oxide MeSH
• Hydrogen Peroxide MeSH
• Pyrroles MeSH
• Reactive Nitrogen Species MeSH
• Reactive Oxygen Species MeSH
• Plant Proteins MeSH
• S-Nitrosoglutathione MeSH
• S-Nitrosothiols MeSH

S-nitrosylation of protein cysteine thiol groups has recently emerged as a widespread and important reversible post-translational protein modification, involved in redox signalling pathways of nitric oxide and reactive nitrogen species. S-nitrosoglutathione reductase (GSNOR), member of class III alcohol dehydrogenase family (EC 1.1.1.1), is considered the key enzyme in the catabolism of major low molecular S-nitrosothiol, S-nitrosoglutathione, and hence to control the level of protein S-nitrosylation. Changes of GSNOR activity after exposure to different abiotic stress conditions, including low and high temperature, continuous dark and de-etiolation, and mechanical injury, were investigated in important agricultural plants. Significantly higher GSNOR activity was found under normal conditions in leaves of Cucumis spp. genotype sensitive to biotrophic pathogen Golovinomyces cichoracearum. GSNOR activity was generally increased in all studied plants by all types of stress conditions. Strong down-regulation of GSNOR was observed in hypocotyls of etiolated pea plants, which did not recover to values of green plants even 168 h after the transfer of etiolated plants to normal light regime. These results point to important role of GSNOR during normal plant development and in plant responses to several types of abiotic stress conditions.

• MeSH
• Aldehyde Oxidoreductases metabolism   MeSH
• Ascomycota pathogenicity   MeSH
• Cucumis melo enzymology   genetics   microbiology   MeSH
• Cucumis sativus enzymology   genetics   microbiology   MeSH
• Stress, Physiological * MeSH
• Pisum sativum enzymology   microbiology   MeSH
• Hypocotyl enzymology   MeSH
• Stress, Mechanical MeSH
• Cold Temperature MeSH
• Heat-Shock Response MeSH
• Light MeSH
• Plant Development MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Aldehyde Oxidoreductases MeSH
• formaldehyde dehydrogenase, glutathione-independent MeSH Browser

Various genetic and physiological aspects of resistance of Lycopersicon spp. to Oidium neolycopersici have been reported, but limited information is available on the molecular background of the plant-pathogen interaction. This article reports the changes in nitric oxide (NO) production in three Lycopersicon spp. genotypes which show different levels of resistance to tomato powdery mildew. NO production was determined in plant leaf extracts of L. esculentum cv. Amateur (susceptible), L. chmielewskii (moderately resistant) and L. hirsutum f. glabratum (highly resistant) by the oxyhaemoglobin method during 216 h post-inoculation. A specific, two-phase increase in NO production was observed in the extracts of infected leaves of moderately and highly resistant genotypes. Moreover, transmission of a systemic response throughout the plant was observed as an increase in NO production within tissues of uninoculated leaves. The results suggest that arginine-dependent enzyme activity was probably the main source of NO in tomato tissues, which was inhibited by competitive reversible and irreversible inhibitors of animal NO synthase, but not by a plant nitrate reductase inhibitor. In resistant tomato genotypes, increased NO production was localized in infected tissues by confocal laser scanning microscopy using the fluorescent probe 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate. NO production observed in the extracts from pathogen conidia, together with elevated NO production localized in developing pathogen hyphae, demonstrates a complex role of NO in plant-pathogen interactions. Our results are discussed with regard to a possible role of increased NO production in pathogens during pathogenesis, as well as local and systemic plant defence mechanisms.

• MeSH
• Ascomycota cytology   physiology   MeSH
• Time Factors MeSH
• Plant Leaves cytology   metabolism   microbiology   MeSH
• Plant Diseases microbiology   MeSH
• Nitric Oxide biosynthesis   MeSH
• Plant Extracts metabolism   MeSH
• Solanum lycopersicum cytology   metabolism   microbiology   MeSH
• Spores, Fungal physiology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Nitric Oxide MeSH
• Plant Extracts MeSH