Seed germination or dormancy status is strictly controlled by endogenous phytohormone and exogenous environment signals.Abscisic acid(ABA)is the important phytohormone to suppress seed germination.Ambient high tempera...Seed germination or dormancy status is strictly controlled by endogenous phytohormone and exogenous environment signals.Abscisic acid(ABA)is the important phytohormone to suppress seed germination.Ambient high temperature(HT)also suppressed seed germination,or called as secondary seed dormancy,through upregulating ABI5,the essential component of ABA signal pathway.Previous result shows that appropriate nitric oxide(NO)breaks seed dormancy through triggering S-nitrosoglutathion reductase(GSNOR1)-dependent S-nitrosylation modification of ABI5 protein,subsequently inducing the degradation of ABI5.Here we found that HT induced the degradation of GSNOR1 protein and reduced its activity,thus accumulated more reactive nitrogen species(RNS)to damage seeds viability.Furthermore,HT increased the S-nitrosylation modification of GSNOR1 protein,and triggered the degradation of GSNOR1,therefore stabilizing ABI5 to suppress seed germination.Consistently,the ABI5 protein abundance was lower in the transgenic line overexpressing GSNOR1,but higher in the gsnor mutant after HT stress.Genetic analysis showed that GSNOR1 affected seeds germination through ABI5 under HT.Taken together,our data reveals a new mechanism by which HT triggers the degradation of GSNOR1,and thus stabilizing ABI5 to suppress seed germination,such mechanism provides the possibility to enhance seed germination tolerance to HT through genetic modification of GNSOR1.展开更多
Flowering is one of the most important phenological periods,as it determines the timing of fruit maturation and seed dispersal.To date,both nitric oxide(NO)and DNA demethylation have been reported to regulate flowerin...Flowering is one of the most important phenological periods,as it determines the timing of fruit maturation and seed dispersal.To date,both nitric oxide(NO)and DNA demethylation have been reported to regulate flowering in plants.However,there is no compelling experimental evidence for a relationship between NO and DNA demethylation during plant flowering.In this study,an NO donor and a DNA methylation inhibitor were used to investigate the involvement of DNA demethylation in NO-mediated tomato(Solanum lycopersicum cv.Micro-Tom)flowering.The results showed that the promoting effect of NO on tomato flowering was dose-dependent,with the greatest positive effect observed at 10μmol L^(-1) of the NO donor S-nitrosoglutathione(GSNO).Treatment with 50μmol L^(-1) of the DNA methylation inhibitor 5-azacitidine(5-AzaC)also significantly promoted tomato flowering.Moreover,GSNO and 5-AzaC increased the peroxidase(POD)and catalase(CAT)activities and cytokinin(CTK)and proline contents,while they reduced the gibberellic acid(GA3)and indole-3-acetic acid(IAA)contents.Co-treatment with GSNO and 5-AzaC accelerated the positive effects of GSNO and 5-AzaC in promoting tomato flowering.Meanwhile,compared with a GSNO or 5-AzaC treatment alone,co-treatment with GSNO+5-AzaC significantly increased the global DNA demethylation levels in different tissues of tomato.The results also indicate that DNA demethylation may be involved in NO-induced flowering.The expression of flowering genes was significantly altered by the GSNO+5-AzaC treatment.Five of these flowering induction genes,ARGONAUTE 4(AGO4A),SlSP3D/SINGLE FLOWER TRUSS(SFT),MutS HOMOLOG 1(MSH1),ZINC FINGER PROTEIN 2(ZFP2),and FLOWERING LOCUS D(FLD),were selected as candidate genes for further study.An McrBC-PCR analysis showed that DNA demethylation of the SFT gene in the apex and the FLD gene in the stem might be involved in NO-induced flowering.Therefore,this study shows that NO might promote tomato flowering by mediating the DNA demethylation of flowering induction genes,and it provides direct evidence for a synergistic effect of NO and DNA demethylation in promoting tomato flowering.展开更多
Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research...Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research on the regulation of high salt stress in this species.In this study,we observed that high salt stress suppressed the growth of U.prolifera and leading to the nitric oxide(NO)accumulation,along with increased gene expression levels and enzyme activity of S-nitrosoglutathione reductase(GSNOR).Treatment with GSNOR inhibitor resulted in elevated NO levels under high salt stress,accompanied by reduced activity of antioxidant enzymes and decreased glutathione(GSH)accumulation,making U.prolifera more sensitive to high salt stress.Conversely,NO scavenger treatment not only reduced NO levels,but also weakened the high salt stress tolerance of U.prolifera.Furthermore,using tandem mass tags(TMT)switch analysis and mass spectrometry,we observed a significant increase in S nitrosylated protein levels in U.prolifera under high salt stress,with further augmentation upon GSNOR inhibitor treatment.We also found high salt stress induced S-nitrosylation(SNO)of glutathione reductase(GR),which is negatively regulated by GSNOR,resulting in increased GR activity.Our results show that under short-term high salt stress,the elevated expression level of GSNOR avoided excessive accumulation of NO,and a certain amount of NO enhanced the activity of antioxidant enzymes through SNO modification,which improve the high salt stress tolerance of U.prolifera,whereas under long-term high salt stress,excessive NO was toxic to U.prolifera.展开更多
Mild traumatic brain injury（TBI）, also called concussion, initiates sequelae leading to motor deficits, cognitive impairments and subtly compromised neurobehaviors. While the acute phase of TBI is associated with ne...Mild traumatic brain injury（TBI）, also called concussion, initiates sequelae leading to motor deficits, cognitive impairments and subtly compromised neurobehaviors. While the acute phase of TBI is associated with neuroinflammation and nitroxidative burst, the chronic phase shows a lack of stimulation of the neurorepair process and regeneration. The deficiency of nitric oxide（NO）, the consequent disturbed NO metabolome, and imbalanced mechanisms of S-nitrosylation are implicated in blocking the mechanisms of neurorepair processes and functional recovery in the both phases. Hypoxia inducible factor-1 alpha（HIF-1α）, a master regulator of hypoxia/ischemia, stimulates the process of neurorepair and thus aids in functional recovery after brain trauma. The activity of HIF-1α is regulated by NO via the mechanism of S-nitrosylation of HIF-1α. S-nitrosylation is dynamically regulated by NO metabolites such as S-nitrosoglutathione（GSNO） and peroxynitrite. GSNO stabilizes, and peroxynitrite destabilizes HIF-1α. Exogenously administered GSNO was found not only to stabilize HIF-1α and to induce HIF-1α-dependent genes but also to stimulate the regeneration process and to aid in functional recovery in TBI animals.展开更多
Complex Ⅲ plays a central role in the mitochondrial respiratory chain transferring electrons from ubiquinol to cytochrome c and pumping protons to the intermembrane space,contributing to the protonmotive force.Furthe...Complex Ⅲ plays a central role in the mitochondrial respiratory chain transferring electrons from ubiquinol to cytochrome c and pumping protons to the intermembrane space,contributing to the protonmotive force.Furthermore,complex Ⅲ can act as a source of O_(2^(·-))in the presence of ubiquinol and antimycin,an expermiental condition in which the oxidation of the cytochrome b hemes is blocked.The O_(2^(·-))dismutation catalyzed by superoxide dismutase produces H2O2,a known second messenger in redox signalling.Results from our laboratory have shown that NO,released from GSNO or from SPER-NO or generated by mtNOS,inhibits electron transfer at ubiquinone-cytochrome b area producing antimycin-like effects.Thus,both antimycin-and NO-inhibited complex Ⅲ showed a high content of cytochromes b in the reduced state(79 and 71%,respectively)and an enhancement in the ubisemiquinone EPR signal at g=1.99(42 and 35%,respectively).As consequence,O_(2^(·-))and H2O2 productions were increased,being the O_(2^(·-))/H_(2)O_(2) ratio equal to 1.98 in accordance with the stoichiometry of the O_(2^(·-))disproportionation.The interruption of the oxidation of cytochromes b by NO leads to an enhancement of the steady-state concentration of UQH·,allowing cytochrome bc1 complex to act as a source of reactive oxygen species in physiological conditions.展开更多
Cross talk between phytohormones, nitric oxide （NO）, and auxin has been implicated in the control of plant growth and development. Two recent reports indicate that NO promoted auxin signaling but inhibited auxin tra...Cross talk between phytohormones, nitric oxide （NO）, and auxin has been implicated in the control of plant growth and development. Two recent reports indicate that NO promoted auxin signaling but inhibited auxin transport probably through S-nitrosylation. However, genetic evidence for the effect of S-nitrosylation on auxin physiology has been lacking. In this study, we used a genetic approach to understand the broader role of S-nitrosylation in auxin physiology in Arabidopsis. We compared auxin signaling and transport in Col-0 and gsnorl-3, a loss-of-function GSNOR1 mutant defective in protein de-nitrosylation. Our results showed that auxin signaling was impaired in the gsnorl-3 mutant as revealed by significantly reduced DR5-GUS/ DR5-GFP accumulation and compromised degradation of AXR3NT-GUS, a useful reporter in interrogating auxin-mediated degradation of Aux/IAA by auxin receptors. In addition, polar auxin transport was compro- mised in gsnorl-3, which was correlated with universally reduced levels of PIN or GFP-PIN proteins in the roots of the mutant in a manner independent of transcription and 26S proteasome degradation. Our results suggest that S-nitrosylation and GSNORl-mediated de-nitrosylation contribute to auxin physiology, and impaired auxin signaling and compromised auxin transport are responsible for the auxin-related morpho- logical phenotypes displayed by the gsnorl-3 mutant.展开更多
基金funded by the National Natural Science Foundation of China(Grants No.31970289).
文摘Seed germination or dormancy status is strictly controlled by endogenous phytohormone and exogenous environment signals.Abscisic acid(ABA)is the important phytohormone to suppress seed germination.Ambient high temperature(HT)also suppressed seed germination,or called as secondary seed dormancy,through upregulating ABI5,the essential component of ABA signal pathway.Previous result shows that appropriate nitric oxide(NO)breaks seed dormancy through triggering S-nitrosoglutathion reductase(GSNOR1)-dependent S-nitrosylation modification of ABI5 protein,subsequently inducing the degradation of ABI5.Here we found that HT induced the degradation of GSNOR1 protein and reduced its activity,thus accumulated more reactive nitrogen species(RNS)to damage seeds viability.Furthermore,HT increased the S-nitrosylation modification of GSNOR1 protein,and triggered the degradation of GSNOR1,therefore stabilizing ABI5 to suppress seed germination.Consistently,the ABI5 protein abundance was lower in the transgenic line overexpressing GSNOR1,but higher in the gsnor mutant after HT stress.Genetic analysis showed that GSNOR1 affected seeds germination through ABI5 under HT.Taken together,our data reveals a new mechanism by which HT triggers the degradation of GSNOR1,and thus stabilizing ABI5 to suppress seed germination,such mechanism provides the possibility to enhance seed germination tolerance to HT through genetic modification of GNSOR1.
基金supported by the National Natural Science Foundation of China(32360743,32072559,and31860568)the National Key Research and Development Program,China(2018YFD1000800)the Fostering Foundation for the Excellent Ph D Dissertation of Gansu Agricultural University,China(YB2022004)。
文摘Flowering is one of the most important phenological periods,as it determines the timing of fruit maturation and seed dispersal.To date,both nitric oxide(NO)and DNA demethylation have been reported to regulate flowering in plants.However,there is no compelling experimental evidence for a relationship between NO and DNA demethylation during plant flowering.In this study,an NO donor and a DNA methylation inhibitor were used to investigate the involvement of DNA demethylation in NO-mediated tomato(Solanum lycopersicum cv.Micro-Tom)flowering.The results showed that the promoting effect of NO on tomato flowering was dose-dependent,with the greatest positive effect observed at 10μmol L^(-1) of the NO donor S-nitrosoglutathione(GSNO).Treatment with 50μmol L^(-1) of the DNA methylation inhibitor 5-azacitidine(5-AzaC)also significantly promoted tomato flowering.Moreover,GSNO and 5-AzaC increased the peroxidase(POD)and catalase(CAT)activities and cytokinin(CTK)and proline contents,while they reduced the gibberellic acid(GA3)and indole-3-acetic acid(IAA)contents.Co-treatment with GSNO and 5-AzaC accelerated the positive effects of GSNO and 5-AzaC in promoting tomato flowering.Meanwhile,compared with a GSNO or 5-AzaC treatment alone,co-treatment with GSNO+5-AzaC significantly increased the global DNA demethylation levels in different tissues of tomato.The results also indicate that DNA demethylation may be involved in NO-induced flowering.The expression of flowering genes was significantly altered by the GSNO+5-AzaC treatment.Five of these flowering induction genes,ARGONAUTE 4(AGO4A),SlSP3D/SINGLE FLOWER TRUSS(SFT),MutS HOMOLOG 1(MSH1),ZINC FINGER PROTEIN 2(ZFP2),and FLOWERING LOCUS D(FLD),were selected as candidate genes for further study.An McrBC-PCR analysis showed that DNA demethylation of the SFT gene in the apex and the FLD gene in the stem might be involved in NO-induced flowering.Therefore,this study shows that NO might promote tomato flowering by mediating the DNA demethylation of flowering induction genes,and it provides direct evidence for a synergistic effect of NO and DNA demethylation in promoting tomato flowering.
基金Supported by the National Natural Science Foundation of China(No.42276100)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research on the regulation of high salt stress in this species.In this study,we observed that high salt stress suppressed the growth of U.prolifera and leading to the nitric oxide(NO)accumulation,along with increased gene expression levels and enzyme activity of S-nitrosoglutathione reductase(GSNOR).Treatment with GSNOR inhibitor resulted in elevated NO levels under high salt stress,accompanied by reduced activity of antioxidant enzymes and decreased glutathione(GSH)accumulation,making U.prolifera more sensitive to high salt stress.Conversely,NO scavenger treatment not only reduced NO levels,but also weakened the high salt stress tolerance of U.prolifera.Furthermore,using tandem mass tags(TMT)switch analysis and mass spectrometry,we observed a significant increase in S nitrosylated protein levels in U.prolifera under high salt stress,with further augmentation upon GSNOR inhibitor treatment.We also found high salt stress induced S-nitrosylation(SNO)of glutathione reductase(GR),which is negatively regulated by GSNOR,resulting in increased GR activity.Our results show that under short-term high salt stress,the elevated expression level of GSNOR avoided excessive accumulation of NO,and a certain amount of NO enhanced the activity of antioxidant enzymes through SNO modification,which improve the high salt stress tolerance of U.prolifera,whereas under long-term high salt stress,excessive NO was toxic to U.prolifera.
基金supported by grants from VA merit awards(BX3401 and RX2090)
文摘Mild traumatic brain injury（TBI）, also called concussion, initiates sequelae leading to motor deficits, cognitive impairments and subtly compromised neurobehaviors. While the acute phase of TBI is associated with neuroinflammation and nitroxidative burst, the chronic phase shows a lack of stimulation of the neurorepair process and regeneration. The deficiency of nitric oxide（NO）, the consequent disturbed NO metabolome, and imbalanced mechanisms of S-nitrosylation are implicated in blocking the mechanisms of neurorepair processes and functional recovery in the both phases. Hypoxia inducible factor-1 alpha（HIF-1α）, a master regulator of hypoxia/ischemia, stimulates the process of neurorepair and thus aids in functional recovery after brain trauma. The activity of HIF-1α is regulated by NO via the mechanism of S-nitrosylation of HIF-1α. S-nitrosylation is dynamically regulated by NO metabolites such as S-nitrosoglutathione（GSNO） and peroxynitrite. GSNO stabilizes, and peroxynitrite destabilizes HIF-1α. Exogenously administered GSNO was found not only to stabilize HIF-1α and to induce HIF-1α-dependent genes but also to stimulate the regeneration process and to aid in functional recovery in TBI animals.
基金supported by research grants from the University of Buenos Aires(UBACYT 200-201-101-00140 and 200-201-301-00731)Agencia Nacional de Promoción Científica y Tecnológica(PICT 2012-0964)Consejo Nacional de Investigaciones Científicas y Técnicas(PIP 112-201-101-00444).
文摘Complex Ⅲ plays a central role in the mitochondrial respiratory chain transferring electrons from ubiquinol to cytochrome c and pumping protons to the intermembrane space,contributing to the protonmotive force.Furthermore,complex Ⅲ can act as a source of O_(2^(·-))in the presence of ubiquinol and antimycin,an expermiental condition in which the oxidation of the cytochrome b hemes is blocked.The O_(2^(·-))dismutation catalyzed by superoxide dismutase produces H2O2,a known second messenger in redox signalling.Results from our laboratory have shown that NO,released from GSNO or from SPER-NO or generated by mtNOS,inhibits electron transfer at ubiquinone-cytochrome b area producing antimycin-like effects.Thus,both antimycin-and NO-inhibited complex Ⅲ showed a high content of cytochromes b in the reduced state(79 and 71%,respectively)and an enhancement in the ubisemiquinone EPR signal at g=1.99(42 and 35%,respectively).As consequence,O_(2^(·-))and H2O2 productions were increased,being the O_(2^(·-))/H_(2)O_(2) ratio equal to 1.98 in accordance with the stoichiometry of the O_(2^(·-))disproportionation.The interruption of the oxidation of cytochromes b by NO leads to an enhancement of the steady-state concentration of UQH·,allowing cytochrome bc1 complex to act as a source of reactive oxygen species in physiological conditions.
文摘Cross talk between phytohormones, nitric oxide （NO）, and auxin has been implicated in the control of plant growth and development. Two recent reports indicate that NO promoted auxin signaling but inhibited auxin transport probably through S-nitrosylation. However, genetic evidence for the effect of S-nitrosylation on auxin physiology has been lacking. In this study, we used a genetic approach to understand the broader role of S-nitrosylation in auxin physiology in Arabidopsis. We compared auxin signaling and transport in Col-0 and gsnorl-3, a loss-of-function GSNOR1 mutant defective in protein de-nitrosylation. Our results showed that auxin signaling was impaired in the gsnorl-3 mutant as revealed by significantly reduced DR5-GUS/ DR5-GFP accumulation and compromised degradation of AXR3NT-GUS, a useful reporter in interrogating auxin-mediated degradation of Aux/IAA by auxin receptors. In addition, polar auxin transport was compro- mised in gsnorl-3, which was correlated with universally reduced levels of PIN or GFP-PIN proteins in the roots of the mutant in a manner independent of transcription and 26S proteasome degradation. Our results suggest that S-nitrosylation and GSNORl-mediated de-nitrosylation contribute to auxin physiology, and impaired auxin signaling and compromised auxin transport are responsible for the auxin-related morpho- logical phenotypes displayed by the gsnorl-3 mutant.
