Scholarly Publications
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This community showcases the academic contributions of faculty and researchers at Banaras Hindu University (BHU) and provides a year-wise compilation of publications across disciplines. Institutional Repository BHU
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PublicationArticle Manganese-induced oxidative stress, ultrastructural changes, and proteomics studies in rice plants(Springer, 2021) Ritika Rajpoot; Rajneesh Kumar Srivastava; Anjana Rani; Poonam Pandey; R.S. DubeyManganese (Mn) is an essential element for plant growth but it becomes phytotoxic at higher concentrations. The effect of Mn-excess in hydroponics medium was examined on growth, oxidative stress, and ultrastructural changes in chloroplasts and mitochondria as well proteomic alterations in rice (Oryza sativa L.) seedlings. Seedlings grown with 1 mM and 2 mM Mn in nutrient medium for 8 days showed decline in length and fresh biomass, and decline in net photosynthetic rate, transpiration rate, and stomatal conductance. Shoots of the seedlings had higher Mn content than roots. Mn-treated seedlings showed increased production of O2·−, H2O2, and .OH, increased lipid peroxidation, increased carbonylation of proteins, and increased proteolytic activity compared to untreated seedlings. Mn-treated seedlings showed disorganization and swelling of chloroplasts with appearance of plastoglobuli in TEM images and deformity in shape of mitochondria. Using confocal microscopy depolarization of mitochondrial membrane was observed marked by green fluorescence of JC-1 dye monomers in Mn-treated roots. Proteomics studies from leaves of Mn-treated seedlings involving 2DE and PDQuest analysis showed differential expression of 23 proteins, among which MALDI-TOF/TOF mass spectrometry analysis revealed Mn-led downregulation of photosynthesis-related proteins, namely oxygen-evolving complex protein associated with PSII, PAP-3, enzyme involved in protein folding peptidyl-prolyl cis-trans isomerase (PPIase) and carbohydrate metabolizing enzymes hydrolase, fructose-bisphosphate aldolase, transketolase, and isocitrate dehydrogenase, whereas ATP-dependent Clp protease, peroxidase, and nucleic acid–binding proteins were downregulated due to Mn treatment. Results indicate that Mn-excess inhibits growth of rice plants with induction of oxidative stress, causing structural alterations in chloroplasts, mitochondria, inhibiting photosynthesis, and downregulating many photosynthesis and carbohydrate metabolism–related proteins. © 2020, Springer-Verlag GmbH Austria, part of Springer Nature.PublicationArticle Alleviation of chromium toxicity in rice seedling using Phyllanthus emblica aqueous extract in relation to metal uptake and modulation of antioxidative defense(Elsevier B.V., 2019) A.K. Pandey; A. Gautam; P. Pandey; R.S. DubeyChromium is a key metal pollutant of the environment. When present in high concentrations in soil it adversely affects plant growth and productivity. Phyllanthus emblica (P. emblica) aqueous extract contains many natural antioxidants, and it has been widely used in traditional medicine for the treatment of severe oxidative stress-related diseases and disorders. The present study was aimed to investigate the possible role of P. emblica aqueous extract in alleviating Cr toxicity effects in rice (Oryza sativa) seedlings in relation to growth attributes, Cr uptake, production of reactive oxygen species (ROS), lipid peroxidation, and activities of antioxidative enzymes. Rice seedlings were raised for 4–8 days in Yoshida nutrient medium in hydroponics containing either 100 μM Cr (K2Cr2O7) or Cr + P. emblica aqueous extract. Cr treatment to the seedlings caused decrease in root and shoots length and fresh biomass, decline in relative water content (RWC) and photosynthetic pigments and increase in root membrane permeability. Uptake of Cr was more in roots than in shoots. Increased production of ROS, increase in lipid peroxidation and increased activities of antioxidative enzymes superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) were observed in Cr-treated seedlings as compared to controls. With the addition of aqueous extract of P. emblica (5 mg ml− 1) in the Cr treatment medium, significant alleviation of Cr-induced decline in growth, biomass, photosynthetic pigments, and reduction in Cr-induced elevated activities of antioxidative enzymes in the seedlings was observed. Our results suggest that P. emblica aqueous extract considerably alleviates the effects of Cr in rice seedlings by suppressing Cr uptake, reducing oxidative stress and modulating activities of antioxidative enzymes. © 2018PublicationArticle Water deficit and aluminum interactive effects on generation of reactive oxygen species and responses of antioxidative enzymes in the seedlings of two rice cultivars differing in stress tolerance(Springer Verlag, 2016) Poonam Pandey; Rajneesh Kumar Srivastava; Ritika Rajpoot; Anjana Rani; Akhilesh Kumar Pandey; R.S. DubeyAluminum (Al) is a major constraint to crop productivity in acid soils, whereas water deficit severely limits crop production in arid and semi-arid regions of the world. The objective of the present study was to examine the effects of both stresses, Al excess and water deficit, individually and in combination on the production of the reactive oxygen species (ROS) superoxide anion (O2˙−), hydrogen peroxide (H2O2), hydroxyl radical, and lipid peroxidation and the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (GPX) in the seedlings of two rice (Oryza sativa L.) cvs. Malviya-36 (sensitive to water deficit and Al) and Vandana (tolerant to water deficit and Al). When 15-day grown seedlings were exposed to water deficit (created with 15 % polyethylene glycol, PEG-6000) or Al (1 mM AlCl3) treatment or both treatments together for 24–72 h, the lengths and fresh weights of root/shoot declined in the seedlings of the sensitive cultivar, whereas in the tolerant seedlings, either little or insignificant decline in these parameters was observed due to the treatments. Biochemical determinations and histochemical studies revealed that under a similar level of water deficit, Al, or combined treatment, seedlings of sensitive cultivar showed a higher level of production of O2˙−, H2O2, hydroxyl radical, and lipid peroxides compared to the tolerant seedlings. Seedlings of tolerant cultivars, both in roots and shoots, had constitutively higher activity levels of antioxidative enzymes SOD, CAT, and GPX and showed a greater increase in activity under water deficit or Al treatment alone or in combination compared to the similarly treated seedlings of sensitive cultivar. Our results suggest that a lower constitutive level of ROS and a high antioxidative enzyme capacity are associated with tolerance to both water deficit and Al excess in rice seedlings. © 2015, Springer-Verlag Berlin Heidelberg.PublicationArticle Exogenous application of calcium and silica alleviates cadmium toxicity by suppressing oxidative damage in rice seedlings(Springer-Verlag Wien, 2015) Rajneesh Kumar Srivastava; Poonam Pandey; Ritika Rajpoot; Anjana Rani; Arti Gautam; R.S. DubeyThe present study was undertaken to examine the possible roles of calcium (Ca2+) and silica (Si) in protection against oxidative damage due to Cd2+ toxicity in rice (Oryza sativa L.) seedlings grown in hydroponics. Rice seedlings raised for 12 days in hydroponics containing Cd(NO3)2 (75 μM) showed reduced growth; increase in the level of reactive oxygen species (ROS) (O2 •− and H2O2), thiobarbituric acid reactive substances (TBARSs) and protein carbonylation; and increase in the activity of antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPX) compared to untreated controls. Exogenously added Ca2+ (2 mM) and Si (200 μM) significantly alleviated negative effect of Cd2+ by restoration of growth of the seedlings, suppression of Cd2+ uptake and restoration of root plasma membrane integrity. The levels of O2 •−, H2O2, lipid peroxidation and protein carbonyls were much lower when Ca2+ and Si were added in the growth medium along with Cd2+ as compared to Cd-alone-treated seedlings. Ca2+ and Si lowered Cd-induced increase in SOD, GPX and APX activities while they elevated Cd-induced decline in CAT activity. Using histochemical staining of O2 •− and H2O2 in leaf tissues, it was further confirmed that added Ca2+ and Si suppressed Cd-induced accumulation of O2 •− and H2O2 in the leaves. The results suggest that exogenous application of Ca2+ and Si appears to be advantageous for rice plants in alleviating Cd2+ toxicity effects by reducing Cd2+ uptake, decreasing ROS production and suppressing oxidative damage. The observations indicate that Ca2+ and Si treatments can help in reducing Cd2+ toxicity in rice plants. © Springer-Verlag Wien 2014.PublicationArticle Cadmium and lead interactive effects on oxidative stress and antioxidative responses in rice seedlings(Springer-Verlag Wien, 2014) Rajneesh Kumar Srivastava; Poonam Pandey; Ritika Rajpoot; Anjana Rani; R.S. DubeyInteractive effects of two heavy metal pollutants Cd and Pb in the growth medium were examined on their uptake, production of reactive oxygen species (ROS), induction of oxidative stress and antioxidative defence responses in Indica rice (Oryza sativa L.) seedlings. When rice seedlings in sand culture were exposed to 150 μM Cd (NO3)2 or 600 μM Pb (CH3COO)2 individually or in combination for 8-16 days, a significant reduction in root/shoot length, fresh weight, relative water content, photosynthetic pigments and increased production of ROS (O2̇- and H2O2) was observed. Both Cd and Pb were readily taken up by rice roots and localisation of absorbed metals was greater in roots than in shoots. When present together in the growth medium, uptake of both the metals Cd and Pb declined by 25-40 %. Scanning electron microscope (SEM) imaging of leaf stomata revealed that Pb caused more distortion in the shape of guard cells than Cd. Dithizone staining of roots showed localisation of absorbed Cd on root hairs and epidermal cells. Both Cd and Pb caused increased lipid peroxidation, protein carbonylation, decline in protein thiol and increase in non-protein thiol. The level of reduced forms of non-enzymic antioxidants glutathione (GSH) and ascorbate (AsA) and their redox ratios (GSH/AsA) declined, whereas the activities of antioxidative enzymes superoxide dismutase (SOD) and guaiacol peroxidase (GPX) increased in metal treated seedlings compared to controls. In-gel activity staining also revealed increased intensities of SOD and GPX isoforms with metal treatments. Catalase (CAT) activity increased during early days (8 days) of metal exposure and declined by 16 days. Results suggest that oxidative stress is an important component in expression of Cd and Pb toxicities in rice, though uptake of both metals gets reduced considerably when present together in the medium. © 2014 Springer-Verlag Wien.PublicationArticle Differential responses of antioxidative defense system to prolonged salinity stress in salt-tolerant and salt-sensitive Indica rice (Oryza sativa L.) seedlings(Springer-Verlag Wien, 2013) Pallavi Mishra; Kumari Bhoomika; R.S. DubeyThe present investigation evaluated the ability of an antioxidative defense system in terms of the tolerance against salinity-induced oxidative stress and also explored a possible relationship between the status of the components of an antioxidative defense system and the salt tolerance in Indica rice (Oryza sativa L.) genotypes. When the seedlings of a salt-sensitive cultivar was grown in sand cultures containing different NaCl concentrations (7 and 14 dS m-1) for 5-20 days, a substantial increase was observed in the rate of superoxide anion (O2·-) production, elevated levels of H2O2 and thiobarbituric acid reactive substances (TBARS) which indicated an enhancement in lipid peroxidation. A declination in the level of thiol clearly indicated an increase in the protein oxidation as well as a decline in the reduced forms of ascorbate (AsA) and glutathione (GSH) and the ratios of their reduced to oxidized forms occurred in the salt-sensitive seedlings. Similar treatment caused a very little alteration or no change in the levels of these components in the seedlings of salt-tolerant cultivar. The activity of antioxidative enzymes superoxide dismutase (SOD), its isoform Cu/Zn-SOD and ascorbate peroxidase (APX) increased in both the cultivars against salinity. In salt-sensitive seedlings, the activity of the various enzymes, guaiacol peroxidase (GPX), catalase (CAT), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) increased at moderate salinity treatment of 7 dS m-1 NaCl while the activities of these enzymes declined with higher salinity level of 14 dS m-1 NaCl. However, a consistent increase was observed in the activities of these enzymes of salt-tolerant seedlings with an increase in the duration and the level of the salinity treatment. The results suggest that a higher status of antioxidants (AsA and GSH) and a coordinated higher activity of the enzymes (SOD, CAT, GPX, APX, and GR) can serve as the major determinants in the model for depicting salt tolerance in Indica rice seedlings. © 2011 Springer-Verlag.PublicationArticle Oxidative stress, protein carbonylation, proteolysis and antioxidative defense system as a model for depicting water deficit tolerance in Indica rice seedlings(Kluwer Academic Publishers, 2013) Samantha Pyngrope; Kumari Bhoomika; R.S. DubeyWater deficit is an important constraint to rice (Oryza sativa L.) productivity. The present study was undertaken to investigate whether the level of oxidative stress, carbonylation of proteins, proteolysis and status of antioxidative defense could serve as a model to distinguish water deficit tolerant and sensitive rice cultivars. When 10-day-grown seedlings of two rice cultivars, Malviya-36 (drought-sensitive) and Brown Gora (drought-tolerant) were subjected to -1. 0 and -2. 1 MPa water deficit treatments for 24-72 h with polyethylene glycol 6000 in the medium, a greater decline in the growth of the seedlings and levels of leaf water potential, relative water content, Chl a, Chl b, carotenoids and greater increase in leaf water loss were observed in the sensitive cultivar than the tolerant. Under similar level of water deficit seedlings of sensitive cultivar showed higher level of superoxide anion generation, H2O2, lipid peroxidation and proteolysis in roots as well as shoots compared to the tolerant. Drought-tolerant cultivar had higher constitutive level of antioxidative enzymes superoxide dismutase and catalase and the activities of these two enzymes alongwith of guaiacol peroxidase showed greater increase in this cultivar under water deficit compared to the sensitive. A significant decline in the level of protein thiol and a higher increase in protein carbonyls content, also confirmed by protein gel blot analysis with an antibody against 2,4-dinitrophenylhydrazine was observed in the seedlings of drought sensitive cv. Malviya-36 compared to the tolerant cv. Brown Gora when subjected to similar level of water deficit. Seedlings of drought sensitive cultivar, under water deficit, showed higher proteolytic activity, higher number of in-gel activity stained proteolytic bands and higher expression of oxidized proteins in roots compared to the tolerant cultivar. Results suggest that poor capacity of antioxidative enzymes could be, at least partly, correlated with water deficit sensitivity of sensitive cultivar and that higher activity of antioxidative enzymes superoxide dismutase, catalase, guaiacol peroxidase, low proteolytic activity, lower level of protein carbonyls and protein thiolation could serve as a model to depict water deficit tolerance in Indica rice seedlings. © 2012 Springer Science+Business Media Dordrecht.PublicationArticle Salicylic acid alleviates aluminum toxicity in rice seedlings better than magnesium and calcium by reducing aluminum uptake, suppressing oxidative damage and increasing antioxidative defense(2013) Poonam Pandey; Rajneesh Kumar Srivastava; R.S. DubeyAluminum toxicity is a major constraint to crop production in acid soils. The present study was undertaken to examine the comparative ameliorating effects of salicylic acid, Ca and Mg on Al toxicity in rice (Oryza sativa L.) seedlings grown in hydroponics. Al treatment (0.5 mM AlCl3) caused decrease in plant vigour, loss of root plasma membrane integrity, increased contents of O2•-, H2O2, lipid peroxidation, protein carbonyls and decline in the level of protein thiol. Al treatment caused significant changes in activity of antioxidative enzymes in rice seedlings. Exogenously added salicylic acid (60 μM), Ca (1 mM) and Mg (0.25 mM) significantly alleviated Al toxicity effects in the seedlings marked by restoration of growth, suppression ofAl uptake, restoration of root plasma membrane integrity and decline in O2•-, H 2O2, lipid peroxidation and protein carbonyl contents. Salicylic acid, Ca and Mg suppressed Al-induced increase in SOD, GPX and APX activities while it elevated Al-induced decline in CAT activity. By histochemical staining of O2•- using NBT and H 2O2 using DAB, it was further confirmed that added salicylic acid, Ca orMg decreasedAl-induced accumulation ofO2 •- and H2O2 in the leaf tissues. Results indicate that exogenously added salicylic acid, Ca or Mg alleviates Al toxicity in rice seedlings by suppressing Al uptake, restoring root membrane integrity, reducing ROS level and ROS induced oxidative damage and regulating the level of antioxidative enzyme activities. Further salicylic appears to be superior toMg and Ca in alleviating Al toxicity effects in rice plants. © Springer Science+Business Media New York 2013.PublicationArticle Differential responses of antioxidant enzymes to aluminum toxicity in two rice (Oryza sativa L.) cultivars with marked presence and elevated activity of Fe SOD and enhanced activities of Mn SOD and catalase in aluminum tolerant cultivar(2013) Kumari Bhoomika; Samantha Pyngrope; R.S. DubeySeedlings of two Indica rice (Oryza sativa L.) cvs. HUR-105 and Vandana, differing in Al-tolerance were used to identify the key mechanisms involved in their differential behaviour towards Al toxicity. Cv. HUR-105 appeared to be Al sensitive by showing significant reduction (p ≤ 0.01) in root/shoot length, fresh weight, dry weight and water content in presence of 421 μM Al3+ in growth medium whereas cv. Vandana appeared to be fairly Al3+ tolerant. A conspicuous and significant reduction in dry weight of root and shoot was observed in Al sensitive cv. HUR-105 with 178 μM Al3+ treatment for 3 days. Al was readily taken up by the roots and transported to shoots in both the rice cultivars. Localization of absorbed Al was always greater in roots than in shoots. Our results of the production of reactive oxygen species (ROS) H2O2 and O2 .- and activities of major antioxidant enzymes such as total superoxide dismutase (SOD), Cu/Zn SOD, Mn SOD, Fe SOD, catalase (CAT) and guaiacol peroxidase revealed Al induced higher oxidative stress, greater production of ROS and lesser capacity to scavenge ROS in cv. HUR-105 than Vandana. With Al treatment, higher oxidative stress was noted in shoots than in roots. Greatly enhanced activities of SOD (especially Fe and Mn SOD) and CAT in Al treated seedlings of cv. Vandana suggest the role of these enzymes in Al tolerance. Furthermore, a marked presence of Fe SOD in roots and shoots of the seedlings of Al tolerant cv. Vandana and its significant (p ≤ 0.01) increase in activity due to Al-treatment, appears to be the unique feature of this cultivar and indicates a vital role of Fe SOD in Al-tolerance in rice. © 2013 Springer Science+Business Media Dordrecht.PublicationArticle Nitric oxide alleviates manganese toxicity by preventing oxidative stress in excised rice leaves(2012) Sarita Srivastava; R.S. DubeyIn the present study, we have investigated the effects of nitric oxide (NO) on alleviating manganese (Mn)-induced oxidative stress in rice leaves. Exogenous MnCl 2 treatment to excised rice leaves for 24 and 48 h resulted in increased production of H 2O 2 and lipid peroxides, decline in the levels of antioxidants, glutathione and ascorbic acid, and increased activities of antioxidative enzymes, superoxide dismutase, guaiacol peroxidase, catalase, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. Treatment of rice leaves with 100 μM sodium nitroprusside (SNP), a NO donor, was effective in reducing Mn-induced increased levels of H 2O 2, lipid peroxides and increased activities of antioxidative enzymes. The levels of reduced ascorbate and glutathione were considerably recovered due to SNP treatment. The effect of SNP was reversed by the addition of NO scavenger, 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (c-PTIO) suggesting that ameliorating effect of SNP is due to release of NO. The results indicate that MnCl 2 induces oxidative stress in excised rice leaves, lowers the levels of reduced ascorbate and glutathione, and elevates activities of the key antioxidative enzymes. NO appears to provide a protection to the rice leaves against Mn-induced oxidative stress and that exogenous NO application could be advantageous in combating the deleterious effects of Mn-toxicity in rice plants. © 2011 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.