Browsing by Author "Arvind Kumar Dubey"

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GABA accretion reduces Lsi-1 and Lsi-2 gene expressions and modulates physiological responses in Oryza sativa to provide tolerance towards arsenic
(Nature Publishing Group, 2017) Navin Kumar; Arvind Kumar Dubey; Atul Kumar Upadhyay; Ambedkar Gautam; Ruma Ranjan; Saripella Srikishna; Nayan Sahu; Soumit Kumar Behera; Shekhar Mallick
GABA counteracts wide range of stresses through regulation of GABA shunt pathway in plants. Although, GABA assisted tolerance against As toxicity in plants is still unexplored. We have examined GABA induced tolerance in rice seedlings with two exposure periods of GABA i.e., short term and long term. Results showed that accumulation of GABA reduced the expressions of Lsi-1 and Lsi-2 transporter genes, which ultimately decreased the accumulation of As in rice seedlings. The accumulation of GABA also modulated the gene expression of GABA shunt pathway and activity of antioxidant enzymes, which strongly induced the tolerance in plants. Antioxidant enzymes such as CAT, POD, GPX and SOD showed maximum alteration in activity with GABA accretion. In both exposure periods, long term accumulation of GABA was highly efficient to provide tolerance to plants against As(III), while higher level of GABA at short term was toxic. Tolerance responses of GABA towards As(III) was reflected by minimal changes in various physiological (WUE, A, gs, PhiPS2, qp, NPQ, ETR and Trmmol) and growth parameters with concomitant accumulation. Oxidative stress marker such as TBARS and H2O2 contents were reduced with GABA accumulation. These results suggested that GABA sturdily inhibits As accumulation and provides tolerance towards As(III). © 2017 The Author(s).
GABA mediated reduction of arsenite toxicity in rice seedling through modulation of fatty acids, stress responsive amino acids and polyamines biosynthesis
(Academic Press, 2019) Navin Kumar; Ambedkar Gautam; Arvind Kumar Dubey; Ruma Ranjan; Ashutosh Pandey; Babita Kumari; Gayatri Singh; Sachin Mandotra; Puneet Singh Chauhan; Saripella Srikrishna; Venkatesh Dutta; Shekhar Mallick
γ-aminobutyric acid (GABA) is a free amino acid, which helps to counteract biotic and abiotic stresses in plants. In the present study, two concentrations of GABA, i.e., 0.5 mM and 1 mM were applied to examine the tolerance of rice seedlings against As(III) (25 µM) toxicity, through the modulations of fatty acids (FAs), stress responsive amino acids (AAs) and polyamines (PAs) biosynthesis. Exogenous GABA (0.5 mM) application significantly reduced the H 2 O 2 and TBARS levels and recovered the growth parameters against As(III) stressed rice seedlings. Simultaneously, co-application of GABA (0.5 and 1 mM) and As(III), consistently enhanced the level of unsaturated fatty acids (USFA) (cis-10-pentadecanoic acid, oleic acid, α-linolenic acid and γ-linolenic acid), which was higher than saturated fatty acid (SFA). Among the USFAs, level of linolenic acid was found to be always higher with GABA application. Similarly, elevated level of AAs (proline, methionine, glutamic acid and cysteine) was also observed with the application of GABA (0.5 and 1 mM) in As(III) stressed seedlings. GABA also enhanced the expression of genes involved in the polyamine synthesis pathway namely arginine decarboxylase (AD), spermine (SPM) and spermidine (SPD) synthase against As(III) treatments, which was higher in roots than in shoots, resulting in enhanced root PAs level. Contrarily, the expression of S-adenosylmethionine decarboxylase (S-AMD) was significantly higher in shoots. Among all the PAs, level of putrescine (PUT) was found to be highest with GABA application. Overall, the study demonstrates that GABA (0.5 mM) at lower concentration plays a vital role in As(III) tolerance by enhancing the biosynthesis of USFA, AA and PA, reducing the level of TBARS and H 2 O 2 in rice seedlings. © 2019 Elsevier Inc.
Genome-wide profiling of drought-tolerant Arabidopsis plants over-expressing chickpea MT1 gene reveals transcription factors implicated in stress modulation
(Springer Science and Business Media Deutschland GmbH, 2022) Sanoj Kumar; Ankita Yadav; Nasreen Bano; Arvind Kumar Dubey; Rita Verma; Ankesh Pandey; Anil Kumar; Sumit Bag; Sudhakar Srivastava; Indraneel Sanyal
Drought, a major abiotic limiting factor, could be modulated with in-built reprogramming of plants at molecular level by regulating the activity of plant developmental processes, stress endurance and adaptation. The transgenic Arabidopsis thaliana over-expressing metallothionein 1 (MT1) gene of desi chickpea (Cicer arietinum L.) was subjected to transcriptome analysis. We evaluated drought tolerance of 7 days old plants of Arabidopsis thaliana in both wild-type (WT) as well as transgenic plants and performed transcriptome analysis. Our analysis revealed 24,737 transcripts representing 24,594 genes out of which 5,816 were differentially expressed genes (DEGs) under drought conditions and 841 genes were common in both genotypes. A total of 1251 DEGs in WT and 2099 in MT1 were identified in comparison with control. Out of the significant DEGs, 432 and 944 were upregulated, whereas 819 and 1155 were downregulated in WT and MT1 plants, respectively. The physiological and molecular parameters involving germination assay, root length measurements under different stress treatments and quantitative expression analysis of transgenic plants in comparison to wild-type were found to be enhanced. CarMT1 plants also demonstrated modulation of various other stress-responsive genes that reprogrammed themselves for stress adaptation. Amongst various drought-responsive genes, 24 DEGs showed similar quantitative expression as obtained through RNA sequencing data. Hence, these modulatory genes could be used as a genetic tool for understanding and delineating the mechanisms for fine-tuning of stress responses in crop plants. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Metallothionein (MT1): A molecular stress marker in chickpea enhances drought and heavy metal stress adaptive efficacy in transgenic plants
(Elsevier B.V., 2022) Sanoj Kumar; Ankita Yadav; Rita Verma; Arvind Kumar Dubey; Shiv Narayan; Ankesh Pandey; Anshu Sahu; Sudhakar Srivastava; Indraneel Sanyal
Metallothioneins (MTs) are diverse class of cysteine-rich proteins having metal-chelation properties. The role of MTs has been demonstrated in different abiotic stresses and MTs have been designated as biomolecular stress markers. Chickpea is an important legume crop supplying proteins to humans, as well as acting as great soil-binders along with nitrogen-fixation capability. The present research deals with the development of transgenic chickpea overexpressing metallothionein type-1 (CarMT1) gene for analyzing its role in stress tolerance against drought and heavy metals. The overexpression construct was designed using binary expression vector, pBI121 and transformed in chickpea desi cultivar, Pusa-362 for functional validation by using sonication-assisted Agrobacterium-mediated transformation. The results indicated high transcript levels under the drought (22-folds) and changes in physiological (photosynthesis rate, transpiration rate, stomatal conductance, water-use efficiency) and biochemical (antioxidant enzymes and compatible solutes) parameters suggesting stress-mitigating roles of CarMT1. The transgenic seeds were evaluated for heavy metal stress adaptation that resulted in better seed survival efficiency under different heavy metal stresses. The results indicated beneficial roles of MT gene in transgenic lines of chickpea in presence of different abiotic stresses, which could pave the way for multi-stress tolerant crop development. © 2022 Elsevier B.V.
Polyamines metabolism and NO signaling in plants
(Elsevier, 2021) Navin Kumar; Ambedkar Gautam; Arvind Kumar Dubey
Nitrogenous compounds such as amino acids (AAs), polyamines (PAs), and nitric oxide (NO) plays a crucial role in the plant development, growth, and signaling. Among these compounds, PAs are ubiquitous polycationic compounds, which are usually found in all living organisms, including bacteria to plants. Multifunctional PAs mainly interact with the biomolecules such as DNA or protein to strengthen the structure. However, NO is a gaseous signaling molecule, regulates several physiological functions in the plants. In recent studies, PAs found to be induce the biosynthesis of NO, but the exact mechanism remains to be deciphered. In plants, PAs and NO crosstalk regulates the different biological functions such as stress responses and hormone regulations. In light of recent findings, PAs and NO crosstalk have been an emerging topic for researchers. Overall, the nitrogen metabolism and its related compounds are a remarkable research topic, which may be biotechnologically important to develop a high-yielding and stress-resistant crops. © 2022 Elsevier Inc.
Reducing Arsenic Uptake in Cereal Crop Plants with Sugarcane Waste Application: A Comparative Study on the Effects on Physiology, Biochemistry, and Grain Nutrient Status
(Springer, 2023) Ambedkar Gautam; Nikita Basant; Navin Kumar; Kriti; Shiv Naresh Singh; Arvind Kumar Dubey; Gayatri Singh; Babita Kumari; Kavita Shah; Shekhar Mallick
C3 (Oryza sativa L.) and C4 (Zea mays L.) plants differ both in their carbon fixing mechanism, and thus, their responses toward stresses also differ. Owing to the mutually competitive nature of uptake between phosphate (iP) and arsenate (AsV) in plants, and given that the level of sucrose is also influenced by iP, interplay of their uptake mechanisms eventually results in reducing the AsV uptakes. The present study intends to comparatively assess the reduction in AsIII and AsV uptake and its toxicity between Oryza sativa L. and Zea mays L. when cultivated with sucrose-containing sugarcane wastes (SWs; bagasse, molasses, and pressmud) conducted under a simulated outdoor pot experiment. Overall improvement in growth, physiological performance, stress, and antioxidant response was exhibited in both the plants with SWs application. The SWs application also improved soil physiochemical parameters viz, pH, EC, OC, OM, and micronutrients. Application of SW also reduced the iAs accumulation in grains of both rice (50–87%) and maize (70–96%), along with enhancement in Fe (142%, and 122%, respectively), and Zn (132% and 131%, respectively). Most of the 17 grain’s amino acids (AAs) increased in maize against iAs stress, whereas Ser decreased in both, and Ile and Gly additionally in rice. Essential AAs viz. Phe, Thr, and Met are influenced negatively by iAs, whereas nonessential AAs viz. Cys, Ser, Pro, Gly in both the plant grains are positively influenced by iP and negatively by OC. Thus, the application of SWs containing residual sucrose > 9.5 µM g−1, through a fertilizer formulation or by direct soil amendments in iAs-contaminated soil can be an agronomic practice to reduce the iP fertilization and limit the iAs contamination in the food-chain. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Sucrose plays key role in amelioration of arsenic induced phytotoxicity through modulating phosphate and silicon transporters, physiological and biochemical responses in C3 (Oryza sativa L.) and C4 (Zea mays L.)
(Elsevier B.V., 2020) Ambedkar Gautam; Navin Kumar; Arvind Kumar Dubey; Ruma Ranjan; Nayan Sahu; Soumit Kumar Behera; Kavita Shah; Rudra Deo Tripathi; Shekhar Mallick
Sucrose is a precursor for several vital biomolecules and essential for growth of the plant. The present study investigated the interrelationship between sucrose (25 μM) and PO4 (iP) in amelioration of arsenic (iAs) [60 μM of AsIII and AsV] toxicity in C3 (Oryza sativa) and C4 (Zea mays) plants. Application of sucrose recovered the iAs induced phytotoxicity, morphological and physiological parameters in both C3 and C4 plant seedlings. Alternatively, iAs accumulation enhanced the endogenous level of sucrose in the seedlings. Also, sucrose suppressed the gene expression of low silicon transporters in both C3 and C4 plants, resulting in lower iAs uptake. Presence of iP, suppressed expression of root iP transporters which coincided with reduced iAs accumulation in maize root (23 %) over its AsIII, and that in shoots of both of C3 (12 %) and C4 (35 %) seedlings over AsV. However, the iP transporters in rice [OsPT-1, 6 & 9] and in maize (ZmPHT1;6, ZmPHT2;1, ZmPHT1;1), shoot and root, respectively, were upregulated with sucrose application, enhancing the iP accumulation. Sucrose application reduced the level of H2O2 and TBARS in both plants, while enhanced the thiolic compounds (GSH, cysteine and NPSH) and activities of antioxidant enzymes (APX, GPX and SOD) against iAs toxicity under both available and iP deprived conditions. The physiological parameters such as A, PhiPS2, gs and qP recovered whereas, NPQ was reduced with sucrose application, towards iAs treatments in both the seedlings. Overall, the results indicate that sucrose plays a vital role in the amelioration of iAs induced toxicity through modulation of iP and low silicon transporters, resulting in reducing the iAs accumulation, physiological parameters and antioxidants. © 2019 Elsevier B.V.