Publications of NIPGR Scientists
Permanent URI for this communityhttps://ndkr-library.nipgr.ac.in/handle/123456789/1
Browse
10 results
Search Results
Item Nitric oxide-mediated modulation of photorespiratory enzymes and photochemical components in leaves of pea plants (Pisum sativum)(John Wiley & Sons, 2026) Saini, Deepak; Bharath, Pulimamidi; Gahir, Shashibhushan; Pandey, Jayendra; Vemula, Chandra Kaladhar; Gupta, Kapuganti Jagadis; Subramanyam, Rajagopal; Raghavendra, Agepati SThe photorespiratory metabolism safeguards photosynthesis against abiotic and biotic stress. Nitric oxide (NO) and reactive oxygen species (ROS) levels rise in plants during abiotic stress. Low concentrations of NO or ROS are beneficial as signalling molecules, but they can be toxic to plant cells at high concentrations. ROS are known to modulate photorespiration; however, it is unclear whether NO affects photorespiratory enzymes and photochemical components simultaneously. We therefore used sodium nitroprusside (SNP) under dark, moderate light (ML), or high light (HL) conditions to simultaneously investigate its impact on photorespiratory enzymes and photochemical components. The NO levels were increased upon SNP exposure in Pisum sativum leaves, particularly under HL conditions. The NO release in leaves was confirmed when the NO scavenger cPTIO (2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt) was present, since it decreased the majority of elevated NO. The nitrosative/oxidative stress in Pisum sativum leaves was confirmed by the increase in nitrosothiols and tyrosine-nitrated proteins, as well as reduced aconitase activity after SNP exposure at HL. The protein levels, mRNA levels, and the enzyme activities of the following four photorespiratory enzymes: glycolate oxidase (GO), hydroxypyruvate reductase (HPR), glycerate kinase (GK), and phosphoglycolate phosphatase (PGLP) were markedly increased under elevated NO conditions. Catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) also showed increased activity, elevated protein and transcript levels upon exposure to SNP. Parallel studies on chlorophyll a fluorescence confirmed that NO restricted electron transport at both PSII and PSI, inhibited photosynthesis and respiration, and damaged photosynthetic pigments. We concluded from this study that NO at high concentrations upregulated photorespiratory enzymes while inhibiting photochemical components such as photosystem II and I (PSII/PSI) simultaneously.Item The interactions of nitric oxide with intracellular redox status and the influence of molecular hydrogen(Elsevier B.V., 2026) Hancock, J T; Corpas, F J; Kolbert, Zs; Silveira, N M; Gupta, Kapuganti JagadisNitric oxide (NO) has a wide range of effects in both animals and plants. It accumulates in cells, especially during stress responses, leading to signalling events. Many of these downstream signals rely on S-nitrosation of proteins, or nitration of proteins, but NO also interacts with a range of other cellular components, including lipids, but also other small reactive compounds. A well-known example of such a NO reaction is with the reactive oxygen species (ROS) superoxide, producing peroxynitrite. One characteristic of cells which is crucial to the control of cellular activity is the intracellular redox state, and this is maintained by compounds such as glutathione (GSH), but also impinged upon by ROS, reactive sulphur compounds such as hydrogen sulfide (H2S), and potentially by hydrogen gas (H2). Into this mix is NO, and here the potential influence of NO on cellular redox is discussed.Item Modulation of nitric oxide mediated by Phytoglobin1 plays a role in salinity tolerance via reduced nitro-oxidative stress in Arabidopsis(Elsevier B.V., 2026) Swain, Jagannath; Babuta, Priyanka; Pandey, Sonika; Samant, Sanjib Bal; Yadav, Reena; Manbir; Hebelstrup, Kim H.; Igamberdiev, Abir U.; Singla-Pareek, Sneh Lata; Pareek, Ashwani; Gupta, Kapuganti JagadisSalinity is one of the major abiotic stresses that induces nitro-oxidative stress, which severely diminishes plant growth, development, and survival by altering various metabolic pathways. Phytoglobin (Pgb) is a nitric oxide (NO) scavenger that plays an important role in various stresses. However, the role of differential levels of phytoglobin1 in regulation of salinity stress induced nitro-oxidative stress in plants is not known. Here we characterized the role of Pgb-mediated NO in salinity tolerance by regulation of nitro-oxidative stress using Pgb1 overexpressing (Pgb1-OE) and silencing lines (pgb1-AS) of Arabidopsis. We found that imposing salinity leads to enhanced expression of Pgb1. NO measurement by both chemiluminescence and DAF-FM-DA suggested that salinity stress induces NO production. Pgb1-OE lines showed reduced levels of NO which is accompanied by reduced ROS, superoxide and H2O2 levels. On the contrary, pgb1-AS lines showed increased NO and ROS under salt stress. Further, gene expression analysis revealed an elevated expression of antioxidant genes in Pgb1-OE line in comparison to WT and pgb1-AS lines under salinity stress. Pgb1-OE lines showed enhanced survival which is correlated with reduced peroxynitrite and tyrosine nitration and opposing effect was observed in pgb1-AS lines along with increased cell death. Taken together, our study revealed that modulation of Pgb1 enhances tolerance to salinity-induced nitro-oxidative stress.Item Nitric oxide-mediated modulation of reproductive resilience under cold stress in chickpea(Frontiers Media S.A., 2025) Kaur, Sarbjeet; Padhiar, Deeksha; Jha, Uday Chand; Kumar, Sanjeev; Sharma, Kamal Dev; Parida, Swarup Kumar; Siddique, Kadambot H. M.; Prasad, P. V. Vara; Nayyar, HarshChickpeas are particularly sensitive to cold stress during the reproductive phase, which can significantly impair pod set and yield. This study examined the role of sodium nitroprusside (SNP), a nitric oxide (NO) donor, in mitigating cold-induced reproductive damage in cold-tolerant (CT) and cold-sensitive (CS) chickpea genotypes. After 100 days of outdoor growth, plants were subjected to cold stress (15/8°C day/night; 12 h photoperiod) for 21 days in walk-in growth chambers during the reproductive stage of development. Control plants were maintained at 25/15°C day/night temperature. SNP treatment (1 mM) was applied exogenously each time, first two days prior to stress onset and then at seven-day intervals (three applications total). Cold stress significantly lowered endogenous NO levels in leaves, anthers, and ovules, particularly in CS genotypes, thereby leading to reduced pollen viability and germination. SNP treatment restored NO and improved reproductive performance, with stronger responses in the CS than the CT genotype. For instance, pollen germination increased by 57.9% in CS versus 17.6% in CT, and pollen viability increased by 28.0% and 13.1%, respectively. Enhanced anther function resulted in a 157.2% increase in pod set and 62.0% higher seed yield in CS. SNP also improved physiological traits, including a 43.9% increase in cellular viability, 18.6% in stomatal conductance, and 41.9% in chlorophyll content in CS genotypes. Cryoprotectants (proline, trehalose, and sucrose) accumulated in anthers, reinforcing cold resilience, while oxidative stress was simultaneously alleviated through reduced malondialdehyde, hydrogen peroxide, and electrolyte leakage, together with the upregulation of both enzymatic (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APx), and glutathione reductase (GR)) and non-enzymatic (ascorbic acid (ASC) and reduced glutathione (GSH)) components. Notably, CS genotypes showed more pronounced improvements from SNP application than CT genotypes, particularly in terms of reproductive success and yield-related traits. These findings highlight the potential of NO donors, such as SNP, to enhance cold tolerance in chickpeas, with promising implications for safeguarding productivity under low-temperature stress, especially in sensitive cultivars.Item Nitric oxide-mediated thermomemory: a new perspective on plant heat stress resilience(Frontiers Media S.A., 2025) Naaz, Sheeba; Pande, Anjali; Laxmi, AshveryaIn the intricate world of plant responses to environmental stress, the concept of thermomemory has emerged as a fascinating and complex phenomenon. Plants, as sessile organisms, continually face the challenge of adapting to fluctuating climates, and the ability to "remember" prior heat stress encounters, a phenomenon known as thermomemory is a testament to their remarkable adaptability. Nitric oxide (NO), a versatile signaling molecule in plant physiology, has been implicated in a myriad of cellular processes crucial for stress adaptation. From its involvement in stomatal regulation to its influence on gene expression and antioxidant defense mechanisms, NO emerges as a central orchestrator in the plant's response to elevated temperatures. Exploration of NO-mediated pathways provides insights into how plants not only cope with immediate heat stress but also retain a memory of these encounters. Unraveling the molecular intricacies of NO's involvement in thermomemory enhances our understanding of the sophisticated strategies employed by plants to navigate a changing climate, offering potential avenues for innovative approaches to enhancing crop resilience and sustainable agriculture.Item Overexpression of phytoglobin1 in rice leads to enhanced nitrogen use efficiency via modulation of nitric oxide(John Wiley & Sons, 2025) Samant, Sanjib Bal; Swain, Jagannath; Yadav, Nidhi; Yadav, Reena; Singh, Pooja; Rai, Preeti; Sheri, Vijay; Sreeman, Sheshshayee; Subramanyam, Rajagopal; Pareek, Ashwani; Gupta, Kapuganti JagadisNitric oxide (NO) is one of the byproducts of nitrogen metabolism. Excess amount of NO is scavenged by phytoglobins. The role of phytoglobin mediated NO homoeostasis in modulation of nitrate transporters was investigated using NO scavenger cPTIO, phytoglobin overexpressing rice and Arabidopsis. Growing plants under low nitrate leads to generation of reduced levels of NO accompanied by elevated expression of high affinity transporters (HATs) such as NRT2.1, NRT2.3 and NRT2.4. Scavenging of NO by cPTIO under optimal nitrate caused enhanced HATs expression. Phytoglobin overexpressing Arabidopsis showed improved growth and enhanced expression of HATs under low nitrogen in comparison to WT. Pretreatment of optimal nitrate grown plants with NO scavenger cPTIO enhanced HATs expression and shifting of these primed plants from optimal to low nitrate leads to further elevation of HATs expression accompanied by enhanced nitrogen uptake and its accumulation with positive effect on growth. Phytoglobin overexpression in rice leads to enhanced HATs expression, improved growth, nitrogen accumulation under low nitrate. Pgb OE lines showed enhanced accumulation of amino acids. Taken together our results suggest an important role of phytoglobins in nitrogen uptake and assimilation.Item Interorgan, intraorgan and interplant communication mediated by nitric oxide and related species(John Wiley & Sons, 2024) Kolbert, Zsuzsanna; Barroso, Juan B; Boscari, Alexandre; Corpas, Francisco J; Gupta, Kapuganti Jagadis; Hancock, John T; Lindermayr, Christian; Palma, José Manuel; Petřivalský, Marek; Wendehenne, David; Loake, Gary JPlant survival to a potential plethora of diverse environmental insults is underpinned by coordinated communication amongst organs to help shape effective responses to these environmental challenges at the whole plant level. This interorgan communication is supported by a complex signal network that regulates growth, development and environmental responses. Nitric oxide (NO) has emerged as a key signalling molecule in plants. However, its potential role in interorgan communication has only recently started to come into view. Direct and indirect evidence has emerged supporting that NO and related species (S-nitrosoglutathione, nitro-linolenic acid) are mobile interorgan signals transmitting responses to stresses such as hypoxia and heat. Beyond their role as mobile signals, NO and related species are involved in mediating xylem development, thus contributing to efficient root-shoot communication. Moreover, NO and related species are regulators in intraorgan systemic defence responses aiming an effective, coordinated defence against pathogens. Beyond its in planta signalling role, NO and related species may act as ex planta signals coordinating external leaf-to-leaf, root-to-leaf but also plant-to-plant communication. Here, we discuss these exciting developments and emphasise how their manipulation may provide novel strategies for crop improvement.Item New insights into nitric oxide biosynthesis underpin lateral root development(Elsevier B.V., 2024) Gupta, Kapuganti Jagadis; Yadav, Nidhi; Kumari, Aprajita; Loake, Gary J.In recent years, nitric oxide (NO) has emerged as a key redox signaling molecule in plants functioning in the regulation of key developmental programs and the orchestration of responses to a plethora of environmental cues (Kolbert et al., 2019). The predominant route for the transfer of NO bioactivity is through S-nitrosylation, the addition of an NO moiety to a protein cysteine thiol to form an S-nitrosothiol (Yun et al., 2011). Specificity for this process is established by the structural constraints imposed by tertiary protein structure in gating access to given cysteine redox switches and associated proteins that can either facilitate the addition or removal of the NO moiety at these residues (Umbreen et al., 2018).Item Nitric oxide, energy and redox-dependent responses to hypoxia(Oxford University Press, 2024) Samant, Sanjib Bal; Yadav, Nidhi; Swain, Jagannath; Joseph, Josepheena; Kumari, Aprajita; Praveen, Afsana; Sahoo, Ranjan Kumar; Manjunatha, Girigowda; Seth, Chandra Shekar; Singla-Pareek, Sneh Lata; Foyer, Christine H; Pareek, Ashwani; Gupta, Kapuganti JagadisHypoxia occurs when the oxygen levels fall below the levels required for mitochondria to support respiration. Regulated hypoxia is associated with quiescence, particularly in storage organs (seeds) and stem cell niches. In contrast, environmentally-induced hypoxia poses significant challenges for metabolically-active cells that are adapted to aerobic respiration. The perception of oxygen availability through cysteine oxidases, which function as oxygen-sensing enzymes in plants that control the N-degron pathway, and the regulation of hypoxia-responsive genes and processes is essential to survival. Functioning together with reactive oxygen species (ROS), particularly hydrogen peroxide and reactive nitrogen species (RNS), such as nitric oxide (•NO), nitrogen dioxide (•NO2), S‐nitrosothiols (SNOs), and peroxynitrite (ONOO−), hypoxia signaling pathways trigger anatomical adaptations such as formation of aerenchyma, mobilization of sugar reserves for anaerobic germination, formation of aerial adventitious roots and hyponastic response. NO and hydrogen peroxide (H2O2) participate in local and systemic signaling pathways that facilitate acclimation to changing energetic requirements, controlling glycolytic fermentation, the GABA shunt and amino acid synthesis. NO enhances antioxidant capacity and contributes to the recycling of redox equivalents energy metabolism through the phytoglobin (Pgb)-NO cycle. Here, we summarize current knowledge, highlighting the central role of NO and redox regulation in adaptive responses that prevent hypoxia-induced death in challenging conditions such as flooding.Item The emerging roles of nitric oxide and its associated scavengers-phytoglobins-in plant symbiotic interactions(Oxford University Press, 2024) Pathak, Pradeep Kumar; Yadav, Nidhi; Kaladhar, Vemula Chandra; Jaiswal, Rekha; Kumari, Aprajita; Igamberdiev, Abir U.; Loake, Gary J.; Gupta, Kapuganti JagadisA key feature in the establishment of symbiosis between plants and microbes is the maintenance of the balance between the production of the small redox-related molecule, nitric oxide (NO), and its cognate scavenging pathways. During the establishment of symbiosis, a transition from a normoxic to a microoxic environment often takes place, triggering the production of NO from nitrite via a reductive production pathway. Plant hemoglobins [phytoglobins (Phytogbs)] are a central tenant of NO scavenging, with NO homeostasis maintained via the Phytogb–NO cycle. While the first plant hemoglobin (leghemoglobin), associated with the symbiotic relationship between leguminous plants and bacterial Rhizobium species, was discovered in 1939, most other plant hemoglobins, identified only in the 1990s, were considered as non-symbiotic. From recent studies, it is becoming evident that the role of Phytogbs1 in the establishment and maintenance of plant–bacterial and plant–fungal symbiosis is also essential in roots. Consequently, the division of plant hemoglobins into symbiotic and non-symbiotic groups becomes less justified. While the main function of Phytogbs1 is related to the regulation of NO levels, participation of these proteins in the establishment of symbiotic relationships between plants and microorganisms represents another important dimension among the other processes in which these key redox-regulatory proteins play a central role.