Regulation of protein function by reversible S-nitrosation, a post-translational modification based on the attachment of nitroso group to cysteine thiols, has emerged among key mechanisms of NO signalling in plant development and stress responses. S-nitrosoglutathione is regarded as the most abundant low-molecular-weight S-nitrosothiol in plants, where its intracellular concentrations are modulated by S-nitrosoglutathione reductase. We analysed modulations of S-nitrosothiols and protein S-nitrosation mediated by S-nitrosoglutathione reductase in cultivated Solanum lycopersicum (susceptible) and wild Solanum habrochaites (resistant genotype) up to 96 h post inoculation (hpi) by two hemibiotrophic oomycetes, Phytophthora infestans and Phytophthora parasitica. S-nitrosoglutathione reductase activity and protein level were decreased by P. infestans and P. parasitica infection in both genotypes, whereas protein S-nitrosothiols were increased by P. infestans infection, particularly at 72 hpi related to pathogen biotrophy-necrotrophy transition. Increased levels of S-nitrosothiols localised in both proximal and distal parts to the infection site, which suggests together with their localisation to vascular bundles a signalling role in systemic responses. S-nitrosation targets in plants infected with P. infestans identified by a proteomic analysis include namely antioxidant and defence proteins, together with important proteins of metabolic, regulatory and structural functions. Ascorbate peroxidase S-nitrosation was observed in both genotypes in parallel to increased enzyme activity and protein level during P. infestans pathogenesis, namely in the susceptible genotype. These results show important regulatory functions of protein S-nitrosation in concerting molecular mechanisms of plant resistance to hemibiotrophic pathogens.

• Publikační typ
• časopisecké články MeSH

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.

• Klíčová slova
• S-nitrosation, S-nitrosoglutathione reductase, Solanum habrochaites, Solanum lycopersicum, abiotic stress, cadmium, nitric oxide, reactive oxygen species, root growth, salinity,
• MeSH
• aldehydoxidoreduktasy metabolismus   MeSH
• askorbátperoxidasa metabolismus   MeSH
• benzamidy chemie   metabolismus   farmakologie   MeSH
• chlorid sodný farmakologie   MeSH
• fyziologický stres MeSH
• kadmium toxicita   MeSH
• kořeny rostlin účinky léků   růst a vývoj   metabolismus   MeSH
• NADPH-oxidasy metabolismus   MeSH
• nitrosace MeSH
• oxid dusnatý metabolismus   MeSH
• oxidační stres účinky léků   MeSH
• peroxid vodíku metabolismus   MeSH
• pyrroly chemie   metabolismus   farmakologie   MeSH
• reaktivní formy dusíku chemie   metabolismus   MeSH
• reaktivní formy kyslíku chemie   metabolismus   MeSH
• regulace genové exprese u rostlin účinky léků   MeSH
• rostlinné proteiny metabolismus   MeSH
• S-nitrosoglutathion farmakologie   MeSH
• S-nitrosothioly metabolismus   MeSH
• Solanum lycopersicum účinky léků   růst a vývoj   metabolismus   MeSH
• Solanum růst a vývoj   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aldehydoxidoreduktasy MeSH
• askorbátperoxidasa MeSH
• benzamidy MeSH
• chlorid sodný MeSH
• formaldehyde dehydrogenase, glutathione-independent MeSH Prohlížeč
• kadmium MeSH
• N6022 MeSH Prohlížeč
• NADPH-oxidasy MeSH
• oxid dusnatý MeSH
• peroxid vodíku MeSH
• pyrroly MeSH
• reaktivní formy dusíku MeSH
• reaktivní formy kyslíku MeSH
• rostlinné proteiny MeSH
• S-nitrosoglutathion MeSH
• S-nitrosothioly 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
• aldehydoxidoreduktasy metabolismus   MeSH
• Ascomycota patogenita   MeSH
• Cucumis melo enzymologie   genetika   mikrobiologie   MeSH
• Cucumis sativus enzymologie   genetika   mikrobiologie   MeSH
• fyziologický stres * MeSH
• hrách setý enzymologie   mikrobiologie   MeSH
• hypokotyl enzymologie   MeSH
• mechanický stres MeSH
• nízká teplota MeSH
• reakce na tepelný šok MeSH
• světlo MeSH
• vývoj rostlin MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aldehydoxidoreduktasy MeSH
• formaldehyde dehydrogenase, glutathione-independent MeSH Prohlížeč

BACKGROUND AND AIMS: Nitric oxide (NO) is involved in the signalling and regulation of plant growth and development and responses to biotic and abiotic stresses. The photoperiod-sensitive mutant 7B-1 in tomato (Solanum lycopersicum) showing abscisic acid (ABA) overproduction and blue light (BL)-specific tolerance to osmotic stress represents a valuable model to study the interaction between light, hormones and stress signalling. The role of NO as a regulator of seed germination and ABA-dependent responses to osmotic stress was explored in wild-type and 7B-1 tomato under white light (WL) and BL. METHODS: Germination data were obtained from the incubation of seeds on germinating media of different composition. Histochemical analysis of NO production in germinating seeds was performed by fluorescence microscopy using a cell-permeable NO probe, and endogenous ABA was analysed by mass spectrometry. KEY RESULTS: The NO donor S-nitrosoglutathione stimulated seed germination, whereas the NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) had an inhibitory effect. Under WL in both genotypes, PTIO strongly suppressed germination stimulated by fluridone, an ABA inhibitor. The stimulatory effect of the NO donor was also observed under osmotic stress for 7B-1 seeds under WL and BL. Seed germination inhibited by osmotic stress was restored by fluridone under WL, but less so under BL, in both genotypes. This effect of fluridone was further modulated by the NO donor and NO scavenger, but only to a minor extent. Fluorescence microscopy using the cell-permeable NO probe DAF-FM DA (4-amino-5-methylamino-2',7'-difluorofluorescein diacetate) revealed a higher level of NO in stressed 7B-1 compared with wild-type seeds. CONCLUSIONS: As well as defective BL signalling, the differential NO-dependent responses of the 7B-1 mutant are probably associated with its high endogenous ABA concentration and related impact on hormonal cross-talk in germinating seeds. These data confirm that light-controlled seed germination and stress responses include NO-dependent signalling.

• MeSH
• biologické modely MeSH
• cyklické N-oxidy farmakologie   MeSH
• donory oxidu dusnatého farmakologie   MeSH
• fluoresceiny analýza   MeSH
• fyziologický stres * účinky léků   účinky záření   MeSH
• imidazoly farmakologie   MeSH
• kinetika MeSH
• klíčení * účinky léků   účinky záření   MeSH
• kyselina abscisová metabolismus   MeSH
• mutace MeSH
• osmóza účinky léků   účinky záření   MeSH
• oxid dusnatý farmakologie   MeSH
• pyridony farmakologie   MeSH
• regulace genové exprese u rostlin účinky léků   účinky záření   MeSH
• regulátory růstu rostlin metabolismus   MeSH
• S-nitrosoglutathion farmakologie   MeSH
• scavengery volných radikálů farmakologie   MeSH
• semena rostlinná účinky léků   genetika   fyziologie   účinky záření   MeSH
• signální transdukce účinky léků   účinky záření   MeSH
• Solanum lycopersicum účinky léků   genetika   fyziologie   účinky záření   MeSH
• světlo * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide MeSH Prohlížeč
• 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate MeSH Prohlížeč
• cyklické N-oxidy MeSH
• donory oxidu dusnatého MeSH
• fluoresceiny MeSH
• fluridone MeSH Prohlížeč
• imidazoly MeSH
• kyselina abscisová MeSH
• oxid dusnatý MeSH
• pyridony MeSH
• regulátory růstu rostlin MeSH
• S-nitrosoglutathion MeSH
• scavengery volných radikálů MeSH