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1.
In the recent times, plants are facing certain types of environmental stresses, which give rise to formation of reactive oxygen species (ROS) such as hydroxyl radicals, hydrogen peroxides, superoxide anions and so on. These are required by the plants at low concentrations for signal transduction and at high concentrations, they repress plant root growth. Apart from the ROS activities, hydrogen sulfide (H 2S) and nitric oxide (NO) have major contributions in regulating growth and developmental processes in plants, as they also play key roles as signaling molecules and act as chief plant immune defense mechanisms against various biotic as well as abiotic stresses. H 2S and NO are the two pivotal gaseous messengers involved in growth, germination and improved tolerance in plants under stressed and non-stress conditions. H 2S and NO mediate cell signaling in plants as a response to several abiotic stresses like temperature, heavy metal exposure, water and salinity. They alter gene expression levels to induce the synthesis of antioxidant enzymes, osmolytes and also trigger their interactions with each other. However, research has been limited to only cross adaptations and signal transductions. Understanding the change and mechanism of H 2S and NO mediated cell signaling will broaden our knowledge on the various biochemical changes that occur in plant cells related to different stresses. A clear understanding of these molecules in various environmental stresses would help to confer biotechnological applications to protect plants against abiotic stresses and to improve crop productivity. 相似文献
2.
Plants are exposed to a plethora of abiotic stresses such as drought, salinity, heavy metal and temperature stresses at different stages of their life cycle, from germination to seedling till the reproductive phase. As protective mechanisms, plants release signaling molecules that initiate a cascade of stress-signaling events, leading either to programmed cell death or plant acclimation. Hydrogen sulfide (H 2S) and nitric oxide (NO) are considered as new ‘gasotransmitter’ molecules that play key roles in regulating gene expression, posttranslational modification (PTM), as well as cross-talk with other hormones. Although the exact role of NO in plants remains unclear and is species dependent, various studies have suggested a positive correlation between NO accumulation and environmental stress in plants. These molecules are also involved in a large array of stress responses and act synergistically or antagonistically as signaling components, depending on their respective concentration. This study provides a comprehensive update on the signaling interplay between H 2S and NO in the regulation of various physiological processes under multiple abiotic stresses, modes of action and effects of exogenous application of these two molecules under drought, salt, heat and heavy metal stresses. However, the complete picture of the signaling cascades mediated by H 2S and NO is still elusive. Recent researches indicate that during certain plant processes, such as stomatal closure, H 2S could act upstream of NO signaling or downstream of NO in response to abiotic stresses by improving antioxidant activity in most plant species. In addition, PTMs of antioxidative pathways by these two molecules are also discussed. 相似文献
3.
Adverse environmental conditions greatly influence crop production every year and threaten food security. Plants have a range of signaling networks to combat these stresses, in which several stress-responsive genes and regulatory proteins function together. One such important family of proteins, the Stress Associated Protein (SAP) family, has been identified as a novel regulator of multiple stresses. The SAPs possess a characteristic N-terminal A20 zinc-finger domain combined with either AN1 or C2H2 at the C-terminus. SAPs provide tolerance against various abiotic stresses, including cold, salt, drought, heavy metal, and wounding. The majority of SAPs are stress-inducible and have a function in conferring stress tolerance in transgenics. The role of SAPs in regulating biotic stress responses is a newly emerging field among researchers. SAPs interact with many other proteins to execute their functions; however, the detailed mechanism of these interactions needs to be elucidated. In this context, the present review provides a detailed view of the evolution and functions of SAPs in plants. The involvement in crosstalk between abiotic and biotic stress signaling pathways makes SAPs ideal targets to develop crops with tolerance against multiple stresses without any yield penalty. Altogether, we provide current knowledge on SAPs for investigating their role in stress response, which can further be exploited to develop climate-resilient crops through transgene-based, breeding-mediated, or genome-editing approaches. 相似文献
4.
Plants often face a variety of abiotic stresses, which affects them negatively and lead to yield loss. The antioxidant system efficiently removes excessive reactive oxygen species and maintains redox homeostasis in plants. With better understanding of these protective mechanisms, recently the concept of hydrogen sulfide (H 2S) and its role in cell signaling has become the center of attention. H 2S has been recognized as a third gasotransmitter and a potent regulator of growth and development processes such as germination, maturation, senescence and defense mechanism in plants. Because of its gaseous nature, H 2S can diffuse to different part of the cells and balance the antioxidant pools by supplying sulfur to cells. H 2S showed tolerance against a plethora of adverse environmental conditions like drought, salt, high temperature, cold, heavy metals and flood via changing in level of osmolytes, malonaldialdehyde, Na +/K + uptake, activities of H 2S biosynthesis and antioxidative enzymes. It also promotes cross adaptation through persulfidation. H 2S along with calcium, methylglyoxal and nitric oxide, and their cross talk induces the expression of mitogen activated protein kinases as well as other genes in response to stress. Therefore, it is sensible to evaluate and explore the stress responsive genes involved in H 2S regulated homeostasis and stress tolerance. The current article is aimed to summarize the recent updates on H 2S-mediated gene regulation in special reference to abiotic stress tolerance mechanism, and cross adaptation in plants. Moreover, new insights into the H 2S-associated signal transduction pathway have also been explored. 相似文献
5.
Salinity stress is one of the most significant global issues that negatively affect plant growth and development. Modern agricultural practices have expanded the destructive effects of salinity stress, affecting plants through immediate osmotic stress, followed by a slow onset of ionic or hyper-osmotic stress. Plants alteration and resistance to salinity stress involve complex physiological, biochemical, and molecular systems to maintain homeostasis. As of late, the investigation of gaseous molecules in plants has attained much consideration, particularly for abiotic stress. Abiotic stresses generally initiate gasotransmitter (GT) generation in plants. In the interim, these GTs enhance the accumulation and activities of few antioxidant molecules, check the destructiveness of reactive oxygen species (ROS), and improve plant resilience under different stress conditions. The current review presented the role of gaseous molecules in plants under salinity stress, which include nitric oxide (·NO), hydrogen sulfide (H2S), hydrogen gas (H2), carbon monoxide (CO), methane (CH4), and the only gaseous phytohormone ethylene. Further, we highlighted the underlying molecular mechanisms of the gasotransmitter signaling and cross-talks in salinity stress. Also, we presented a general update on the inclusion of GT in salt stress response, including the research gaps and its applications in the advancement of salinity-resistant plants. 相似文献
6.
Nitric oxide (NO) is a bioactive gaseous, multifunctional molecule playing a central role and mediating a variety of physiological processes and responses to biotic and abiotic stresses including heavy metals. The present study investigated whether NO applied exogenously as sodium nitroprusside (SNP) has a protective role against arsenic (As) toxicity (applied as sodium arsenate) in Vigna radiata (mung bean) germinating seeds. Treatment with 75???M SNP significantly improved mung bean seed germination, growth, and decreased the As-accumulation. Furthermore, As-induced oxidative stress measured in terms of malondialdehyde and H 2O 2 contents was lesser upon supplementation of SNP indicating a reactive oxygen species scavenging activity of NO. In addition, supplementation of SNP markedly decreased the activity of superoxide dismutase and stimulated catalase, ??-amylase, protease and slightly changed the H +-ATPase activity. 相似文献
7.
Nitric oxide (NO) has been shown to play an important role in the plant response to biotic and abiotic stresses in Arabidopsis mutants with lower or higher levels of endogenous NO. The exogenous application of NO donors or scavengers has also suggested an important role for NO in plant defense against environmental stress. In this study, rice plants under drought and high salinity conditions showed increased nitric oxide synthase (NOS) activity and NO levels. Overexpression of rat neuronal NO synthase ( nNOS) in rice increased both NOS activity and NO accumulation, resulting in improved tolerance of the transgenic plants to both drought and salt stresses. nNOS-overexpressing plants exhibited stronger water-holding capability, higher proline accumulation, less lipid peroxidation and reduced electrolyte leakage under drought and salt conditions than wild rice. Moreover, nNOS-overexpressing plants accumulated less H 2O 2, due to the observed up-regulation of OsCATA, OsCATB and OsPOX1. In agreement, the activities of CAT and POX were higher in transgenic rice than wild type. Additionally, the expression of six tested stress-responsive genes including OsDREB2A, OsDREB2B, OsSNAC1, OsSNAC2, OsLEA3 and OsRD29A, in nNOS-overexpressing plants was higher than that in the wild type under drought and high salinity conditions. Taken together, our results suggest that nNOS overexpression suppresses the stress-enhanced electrolyte leakage, lipid peroxidation and H 2O 2 accumulation, and promotes proline accumulation and the expression of stress-responsive genes under stress conditions, thereby promoting increased tolerance to drought and salt stresses. 相似文献
8.
Redox signalling in mitochondria plays an important role in myocardial ischaemia/reperfusion (I/R) injury and in cardioprotection. Reactive oxygen and nitrogen species (ROS/RNS) modify cellular structures and functions by means of covalent changes in proteins including among others S‐nitros(yl)ation by nitric oxide (NO) and its derivatives, and S‐sulphydration by hydrogen sulphide (H 2S). Many enzymes are involved in the mitochondrial formation and handling of ROS, NO and H 2S under physiological and pathological conditions. In particular, the balance between formation and removal of reactive species is impaired during I/R favouring their accumulation. Therefore, various interventions aimed at decreasing mitochondrial ROS accumulation have been developed and have shown cardioprotective effects in experimental settings. However, ROS, NO and H 2S play also a role in endogenous cardioprotection, as in the case of ischaemic pre‐conditioning, so that preventing their increase might hamper self‐defence mechanisms. The aim of the present review was to provide a critical analysis of formation and role of reactive species, NO and H 2S in mitochondria, with a special emphasis on mechanisms of injury and protection that determine the fate of hearts subjected to I/R. The elucidation of the signalling pathways of ROS, NO and H 2S is likely to reveal novel molecular targets for cardioprotection that could be modulated by pharmacological agents to prevent I/R injury. 相似文献
9.
Osmotin or osmotin-like proteins have been shown to be induced in several plant species in response to various types of biotic
and abiotic challenges. The protein is generally believed to be involved in protecting the plant against these stresses. Although
some understanding of the possible mechanism underlying the defense function of osmotin against biotic stresses is beginning
to emerge, its role in abiotic stress response is far from clear. We have transformed cotton plants with a tobacco-osmotin
gene, lacking the sequence encoding its 20 amino acid-long, C-terminal vacuolar-sorting motif, under the control of CaMV 35S
promoter. Apoplastic secretion of the recombinant protein was confirmed and the plants were evaluated for their ability to
tolerate drought conditions. Under polyethylene glycol-mediated water stress, the osmotin-expressing seedlings showed better
growth performance. The transformants showed a slower rate of wilting during drought and faster recovery following the termination
of dry conditions in a greenhouse setting. During drought, the leaves from transgenic plants had higher relative water content
and proline levels, while showing reduced H 2O 2 levels, lipid peroxidation and electrolyte leakage. Importantly, following a series of dry periods, the osmotin transformants
performed better in terms of most growth and developmental parameters tested. Most relevant, the fiber yield of transgenic
plants did not suffer as much as that of their non-transgenic counterparts under drought conditions. The results provide direct
support for a protective role of osmotin in cotton plants experiencing water stress and suggest a possible way to achieve
tolerance to drought conditions by means of genetic engineering.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
A study was carried out to assess the protective effects of exogenously applied nitric oxide (NO) in the form of its donor sodium nitroprusside (SNP) to strawberry seedlings ( Fragaria × ananassa cv. Camarosa) grown under iron deficiency (ID), salinity stress or combination of both. The experimental design contained control, 0.1 mM FeSO 4 (ID, Fe deficiency); 50 mM NaCl (S, Salinity) and ID + S. Plants were sprayed with 0.1 mM SNP or 0.1 mM sodium ferrocyanide, an analogue of SNP containing no NO. The deleterious effects of ID + S treatments on plant fresh and dry matters, total chlorophyll and chlorophyll fluorescence were more striking than those caused by the ID or S treatment alone. Furthermore, combination of salinity and iron stress exacerbated electrolyte leakage (EL) and the levels of malondialdehyde (MDA) and hydrogen peroxide (H 2O 2) in plant leaves compared to those in plants grown with either of the single stresses. NO treatment effectively reduced EL, MDA and H 2O 2 in plants grown under stress conditions applied singly or in combination. Salt stress alone and with ID reduced the superoxide dismutase (EC1.15.1.1) and catalase (EC 1.11.1.6) activities but increased that of POD (EC 1.17.1.7). Exogenously applied NO led to significant changes in antioxidant enzyme activities in either ID or S than those by ID+S. Overall, exogenously applied NO was more effective in mitigating the stress‐induced adverse effects on the strawberry plants exposed to a single stress than those due to the combination of both stresses. 相似文献
13.
Gaseous molecules, such as hydrogen sulfide(H_2S)and nitric oxide(NO), are crucial players in cellular and(patho)physiological processes in biological systems. The biological functions of these gaseous molecules, which were first discovered and identified as gasotransmitters in animals, have received unprecedented attention from plant scientists in recent decades. Researchers have arrived at the consensus that H_2S is synthesized endogenously and serves as a signaling molecule throughout the plant life cycle.However, the mechanisms of H_2S action in redox biology is still largely unexplored. This review highlights what we currently know about the characteristics and biosynthesis of H_2S in plants. Additionally,we summarize the role of H_2S in plant resistance to abiotic stress. Moreover, we propose and discuss possible redox-dependent mechanisms by which H_2S regulates plant physiology. 相似文献
14.
The oscillation of intracellular calcium (Ca 2+) concentration is a primary event in numerous biological processes in plants, including stress response. Hydrogen sulfide (H 2S), an emerging gasotransmitter, was found to have positive effects in plants responding to chromium (Cr 6+) stress through interacting with Ca 2+ signaling. While Ca 2+ resemblances H 2S in mediating biotic and abiotic stresses, crosstalk between the two pathways remains unclear. In this study, Ca 2+ signaling interacted with H 2S to produce a complex physiological response, which enhanced the Cr 6+ tolerance in foxtail millet ( Setaria italica). Results indicate that Cr 6+ stress activated endogenous H 2S synthesis as well as Ca 2+ signaling. Moreover, toxic symptoms caused by Cr 6+ stress were strongly moderated by 50 μM H 2S and 20 mM Ca 2+. Conversely, treatments with H 2S synthesis inhibitor and Ca 2+ chelators prior to Cr 6+-exposure aggravated these toxic symptoms. Interestingly, Ca 2+ upregulated expression of two important factors in metal metabolism, MT3A and PCS, which participated in the biosynthesis of heavy metal chelators, in a H 2S-dependent manner to cope with Cr 6+ stress. These findings also suggest that the H 2S dependent pathway is a component of the Ca 2+ activating antioxidant system and H 2S partially contributes Ca 2+-activating antioxidant system. 相似文献
15.
Germins and germin-like proteins ( GLPs) were reported to participate in plant response to biotic and abiotic stresses involving hydrogen peroxide (H 2O 2) production, but their role in mitigating heat stress is poorly understood. Here, we investigated the ability of a Solanum tuberosum L. GLP ( StGLP) gene isolated from the yeast cDNA library generated from heat-stressed potato plants and characterized its role in generating innate and/or acquired thermo-tolerance to potato via genetic transformation. The transgenic plants exhibited enhanced tolerance to gradual heat stress (GHS) compared with sudden heat shock (SHS) in terms of maximal cell viability, minimal ion leakage and reduced chlorophyll breakdown. Further, three StGLP transgenic lines (G9, G12 and G15) exhibited enhanced production of H 2O 2, which was either reduced or blocked by inhibitors of H 2O 2 under normal and heat stress conditions. This tolerance was mediated by up-regulation of antioxidant enzymes (catalase, ascorbate peroxidase and glutathione reductase) and other heat stress-responsive genes ( StHSP70, StHSP20 and StHSP90) in transgenic potato plants. These results demonstrate that H 2O 2 produced by over-expression of StGLP in transgenic potato plants triggered the reactive oxygen species (ROS) scavenging signaling pathways controlling antioxidant and heat stress-responsive genes in these plants imparting tolerance to heat stress. 相似文献
16.
There seems to be no report in the literature on the effect of melatonin (MT) in relieving the detrimental effects of combined application of salt stress (SS) and iron deficiency (ID). Therefore, the effect of MT on the accumulation/synthesis of endogenous nitric oxide (NO) and hydrogen sulphide (H 2S) and how far these molecules are involved in MT-improved tolerance to the combined application of ID and SS in pepper ( Capsicum annuum L) were tested. Hence, two individual trials were set up. The treatments in the first experiment comprised: Control, ID (0.1 mM FeSO 4), SS (100 mM NaCl) and ID + SS. The detrimental effects of combined stresses were more prominent than those by either of the single stress, with respect to growth, oxidative stress and antioxidant defense attributes. Single stress or both in combination improved the endogenous H 2S and NO, and foliar-applied MT (100 µM) led to a further increase in NO and H 2S levels. In the second experiment, 0.1 mM scavenger of NO, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO) and that of H 2S, hypotuarine (HT) were applied along with MT to get further evidence whether NO and H 2S are involved in MT-induced tolerance to ID and SS. MT combined with cPTIO and HT under a single or combined stress showed that NO effect was reversed by the NO scavenger, cPTIO, alone but the H 2S effect was inhibited by both scavengers. These findings suggested that tolerance to ID and SS induced by MT may be involved in downstream signal crosstalk between NO and H 2S. 相似文献
17.
Seedlings of cultivated rice variety ADT43 was investigated after challenging with two different abiotic (drought and salinity) and biotic (sheath blight and bacterial leaf blight pathogens) stresses. Salinity and drought stress reduced the growth of seedlings, mainly the higher conditions (100 mM NaCl and 10?days of drought, respectively). Increased level of MDA content was observed in biotic and abiotic-stress treated seedlings. The highest H 2O 2 content was observed under salinity-stressed seedlings and lower level observed under biotic stress. Superoxide dismutase activity showed a gradual decrease in all stress conditions compared to control. Salinity stress resulted in highest activity of catalase compared to biotic stress. The peroxidase activity of the seedlings was found to be increased under salt and drought stress conditions and the activity decreased under biotic stress. Drought stress resulted in induced expression of POC1 gene whereas the biotic stress showed lower expression level. Suppression of the rice peroxidase would have been the mechanism of overcoming the intrinsic defence in rice by these pathogens. 相似文献
18.
Currently, food security depends on the increased production of cereals such as wheat
( Triticum aestivum L.), which is an important source of calories
and protein for humans. However, cells of the crop have suffered from the
accumulation of reactive oxygen species (ROS), which can cause severe oxidative
damage to the plants, due to environmental stresses. ROS are toxic molecules found in
various subcellular compartments. The equilibrium between the production and
detoxification of ROS is sustained by enzymatic and nonenzymatic antioxidants. In the
present review, we offer a brief summary of antioxidant defense and hydrogen peroxide
(H 2O 2) signaling in wheat plants. Wheat plants increase
antioxidant defense mechanisms under abiotic stresses, such as drought, cold, heat,
salinity and UV-B radiation, to alleviate oxidative damage. Moreover,
H 2O 2 signaling is an important factor contributing to stress
tolerance in cereals. 相似文献
19.
Hydrogen sulfide (H 2S), which has been identified as the third gaseous signaling molecule after nitric oxide (NO) and carbon monoxide (CO), plays an important role in maintaining homeostasis in the cardiovascular system. Endogenous H 2S is produced mainly by three endogenous enzymes: cystathionine β-synthase, cystathionine γ-lyase, and 3-mercaptopyruvate sulfur transferase. Numerous studies have shown that H 2S has a significant protective role in myocardial ischemia. The mechanisms by which H 2S affords cardioprotection include the antifibrotic and antiapoptotic effects, regulation of ion channels, protection of mitochondria, reduction of oxidative stress and inflammatory response, regulation of microRNA expression, and promotion of angiogenesis. Amplification of NO- and CO-mediated signaling through crosstalk between H 2S, NO, and CO may also contribute to the cardioprotective effect. Exogenous H 2S donors are expected to become effective drugs for the treatment of cardiovascular diseases. This review article focuses on the protective mechanisms and potential therapeutic applications of H 2S in myocardial ischemia. 相似文献
20.
Aging involves the time-dependent deterioration of physiological functions attributed to various intracellular and extracellular factors. Cellular senescence is akin to aging and involves alteration in redox homeostasis. This is primarily marked by increased reactive oxygen/nitrogen species (ROS/RNS), inflammatory gene expression, and senescence-associated beta-galactosidase activity, all hallmarks of aging. It is proposed that gasotransmitters which include hydrogen sulfide (H 2S), carbon monoxide (CO), and nitric oxide (NO), may affect redox homeostasis during senescence. H 2S has been independently shown to induce DNA damage and suppress oxidative stress. While an increase in NO levels during aging is well established, the role of H 2S has remained controversial. To understand the role of H 2S during aging, we evaluated H 2S homeostasis in non-senescent and senescent cells, using a combination of direct measurements with a fluorescent reporter dye (WSP-5) and protein sulfhydration analysis. The free intracellular H 2S and total protein sulfhydration levels are high during senescence, concomitant to cystathionine gamma-lyase (CSE) expression induction. Using lentiviral shRNA-mediated expression knockdown, we identified that H 2S contributed by CSE alters global gene expression, which regulates key inflammatory processes during cellular senescence. We propose that H 2S decreases inflammation during cellular senescence by reducing phosphorylation of IκBα and the p65 subunit of nuclear factor kappa B (NF-κB). H 2S was also found to reduce NO levels, a significant source of nitrosative stress during cellular senescence. Overall, we establish H 2S as a key gasotransmitter molecule that regulates inflammatory phenotype and nitrosative stress during cellular senescence. 相似文献
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