Publications of NIPGR Scientists
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Item Unraveling the molecular aspects of iron-mediated OsWRKY76 signaling under arsenic stress in rice(Elsevier B.V., 2023) Mirza, Zainab; Jonwal, Sarvesh; Saini, Himanshu; Sinha, Alok Krishna; Gupta, MeetuArsenic (As) is a significant environmental element that restricts the growth and production of rice plants. Although the role of iron (Fe) to sequester As in rice is widely known, the molecular mechanism regarding As–Fe interaction remains opaque. Here, we show the differential response of two rice varieties (Ratna and Lalat) in terms of their morphological and biochemical changes in the presence of As and Fe. These results together with in-silico screening, gene expression analysis, and protein-protein interaction studies suggest the role of OsWRKY76 in Fe-mediated As stress alleviation. When OsWRKY76 is activated by MAPK signaling, it inhibits the gene expression of Fe transporters OsIRT1 and OsYSL2, which reduces the amount of Fe accumulated. However, MAPK signaling and OsWRKY76 remain down-regulated during Fe supplementation with As, which subsequently encourages the up-regulation of OsIRT1 and OsYSL2. This results in greater Fe content and decreased As accumulation and toxicity. The lower H2O2 and SOD, CAT, and APX activities were likewise seen under the As + Fe condition. Overall, results revealed the molecular aspects of Fe-mediated control of OsWRKY76 signaling and showed that Ratna is a more As tolerant variety than Lalat. Lalat, however, performs better in As stress due to the presence of Fe.Item Protective role of nitric oxide on nitrogen-thiol metabolism and amino acids profiling during arsenic exposure in Oryza sativa L.(Springer Nature Publishing AG, 2020) Praveen, Afsana; Pandey, Ashutosh; Gupta, MeetuNitric oxide (NO) being a signaling molecule inside the plant cells, play significant role in signaling cascades and protection against environmental stresses. However, the protective role of NO in alleviating As toxicity in rice plants is currently not available. In the present study, the level of NO, nitrogen (N), inorganic N (nitrate, ammonium), thiols {TT (Total thiols), NPT (Nonprotein thiol)} and AAs contents along with N assimilating enzymes (NR, GDH, GOGAT) were analyzed after exposure of AsIII/NO treatment alone, and in combination. NO supplementation enhanced the content of N, inorganic N & thiol contents, NR, GOGAT activities, when compared with AsIII exposure alone. In AsIII exposed rice seedlings, content of AAs (except His, Arg, Met) reduced over the control, while supplementation of SNP improved AAs contents, compared to AsIII treatment alone. In conclusion, rice seedlings supplemented with NO tolerate the AsIII toxicity by reducing the N related parameters, thiol contents, altering the AA profile and enhanced the nutritional quality by increasing EAAs (essential amino acids) and NEAAs (non-essential amino acids).Item Transcript profiling reveals potential regulators for oxidative stress response of a necrotrophic chickpea pathogen Ascochyta rabiei(Springer Nature Publishing AG, 2020) Maurya, Ranjeet; Singh, Yeshveer; Sinha, Manisha; Singh, Kunal; Mishra, Pallavi; Singh, Shreenivas Kumar; Verma, Sandhya; Prabha, Kanchan; Kumar, Kamal; Verma, Praveen K.Necrotrophic pathogens experience host-generated oxidative stress during pathogenesis. They overcome such hostile environment by intricate mechanisms which are largely understudied. In this article, reference-based transcriptome analysis of a devastating Ascochyta Blight (AB) disease causing chickpea pathogen Ascochyta rabiei was explored to get insights into survival mechanisms under oxidative stress. Here, expression profling of mock-treated and menadione-treated fungus was carried out by RNA-Seq approach. A signifcant number of genes in response to oxidative stress were overrepresented, suggestive of a robust and coordinated defense system of A. rabiei. A total 73 diferentially expressed genes were fltered out from both the transcriptomes, among them 64 were up-regulated and 9 were found down-regulated. The gene ontology and KEGG mapping were conducted to comprehend the possible regulatory roles of diferentially expressed genes in metabolic networks and biosynthetic pathways. Transcript profling, KEGG pathway and gene ontology-based enrichment analysis revealed 12 (16.43%) stress responsive factors, 25 (34.24%) virulence associated genes, 10 (13.69%) putative efectors and 28 (38.35%) important interacting proteins associated with various metabolic pathways. In addition, genes with diferential expression were further explored for underlying putative pathogenicity factors. We identifed fve genes ST47_g10291, ST47_g9396, ST47_g10294, ST47_g4395, and ST47_g7191 that were common to stress and fungal pathogenicity. The factors recognized in this work can be used to establish molecular tools to explain the regulatory gene networks engaged in stress response of fungal pathogens and disease management.Item Nitric oxide alters nitrogen metabolism and PIN gene expressions by playing protective role in arsenic challenged Brassica juncea L.(Elsevier B.V., 2019) Praveen, Afsana; Pandey, Ashutosh; Gupta, MeetuPlants have ability to adapt themselves through altering their growth process. In the present study, we examined exogenous application of nitric oxide (NO) on nitrogen metabolism and auxin (PIN) gene expression, and its possible role in alleviation of arsenic (As) toxicity in Brassica juncea seedlings. Seven days old hydroponically grown B. juncea seedlings were exposed to AsIII (150 μM), Sodium nitroprusside (NO donor, 100 μM), AsIII + SNP and control (without metal)for 48 h. Experimental results revealed that AsIII stress: enhanced the level of nitrite, NiR activity, NO3− and NH4+content as well as NADH-GOGAT activity; but GDH level decreased; enhanced content of amino acids; upregulated gene expression level of N metabolism and downregulated polar auxin transporter genes (PIN); inhibited plant growth and morphological parameters; increased MDA, H2O2, cysteine, proline content, enzymatic antioxidants (SOD, CAT, APX; GSH, TT, NPT); and decreased nutrient content. AsIII + SNP combination reduced the accumulation of As; improved growth; chlorophyll, protein and mineral nutrient content by scavenging ROS generation; maintained amino acids content; downregulated expression of N metabolism genes and upregulated expression of auxin transporter (PIN) genes . Additional biochemical data depicts reduction in the level of nitrogen related enzymatic activities, and other stress related parameters. Overall, this study provides an integrated view that exogenous SNP (NO donor) supplementation alleviated the inhibitory role of AsIII in B. juncea seedlings by altering nutrients, amino acids and auxin redistribution via expression of nitrogen and PIN gene profiling.Item Senescent hepatocytes in decompensated liver show reduced UPRMT and its key player, CLPP, attenuates senescence in vitro(Elsevier B.V., 2019) Sen, Bijoya; Rastogi, Archana; Nath, Rhisita; Shasthry, Saggere M.; Pamecha, Viniyendra; Pandey, Sonika; Gupta, Kapuganti Jagadis; Sarin, Shiv K.; Trehanpati, Nirupma; Ramakrishna, GayatriBackground and Aims Non-dividing hepatocytes in end-stage liver disease indicates permanent growth arrest similar to senescence. Identifying senescence in vivo is often challenging and mechanisms inhibiting senescence are poorly understood. In lower organisms mitochondrial unfolded protein response (UPRMT) helps in increasing longevity; however, its role in senescence and liver disease is poorly understood. Aim of this study was to identify hepatocyte senescence and role of UPRMT in cryptogenic cirrhosis. Methods Doxorubicin was used to induce senescence in non-neoplastic hepatocytes (PH5CH8) and hepatoma cells (HepG2 and Huh7). Senescence-associated markers and unfolded protein response was evaluated by fluorescence microscopy, immunoblotting and gene expression. Explants/biopsies from normal, fibrosis, compensated and decompensated cirrhosis without any known etiology were examined for presence of senescence and UPRMT by immunohistochemistry and gene expression. Results Accumulation of senescent hepatocytes in cryptogenic cirrhosis was associated with reduced proliferation, increased expression of γH2AX and p21, together with loss of LaminB1. Dysfunctional mitochondria and compromised UPRMT were key features of senescent hepatocytes both in vitro and also in decompensated cirrhosis. Intriguingly, compensated cirrhotic liver mounted strong UPRMT, with high levels of mitochondrial protease, CLPP. Over-expression of CLPP inhibited senescence in vitro, by reducing mitochondrial ROS and altering oxygen consumption. Conclusions Our results implicate a role of hepatocyte senescence in cryptogenic cirrhosis together with a crucial role of UPRMT in preventing hepatocyte senescence. A compromised UPRMT may shift the fate of cirrhotic liver towards decompensation by exaggerating hepatocyte senescence. Restoring CLPP levels at least in cell culture appears as a promising strategy in mitohormesis, thereby, preventing senescence and possibly improving hepatocyte function.Item Ectopic overexpression of vacuolar and apoplastic Catharanthus roseus peroxidases confers differential tolerance to salt and dehydration stress in transgenic tobacco(Springer Science, 2012) Kumar, Santosh; Jaggi, Monika; Sinha, Alok KrishnaCrPrx and CrPrx1 are class III peroxidases previously cloned and characterized from Catharanthus roseus. CrPrx is known to be apoplastic in nature, while CrPrx1 is targeted to vacuoles. In order to study their role in planta, these two peroxidases were expressed in Nicotiana tabacum. The transformed plants exhibited increased peroxidase activity. Increased oxidative stress tolerance was also observed in transgenics when treated with H(2)O(2) under strong light conditions. However, differential tolerance to salt and dehydration stress was observed during germination of T1 transgenic seeds. Under these stresses, the seed germination of CrPrx-transformed plants and wild-type plants was clearly suppressed, whereas CrPrx1 transgenic lines showed improved germination. CrPrx-transformed lines exhibited better cold tolerance than CrPrx1-transformed lines. These results indicate that vacuolar peroxidase plays an important role in salt and dehydration stress over cell wall-targeted peroxidase, while cell wall-targeted peroxidase renders cold stress tolerance.Item A comprehensive study on dehydration-induced antioxidative responses during germination of Indian bread wheat (Triticum aestivum L. em Thell) cultivars collected from different agroclimatic zones(Springer Science, 2012) Garg, Bharti; Jaiswal, Jai P.; Misra, Shrilekha; Tripathi, Bhumi Nath; Prasad, ManojTo explore the adaptability of bread wheat to dehydration stress, we screened 28 cultivars collected from different agroclimatic zones, on the basis of malonaldehyde content as biochemical marker in roots of wheat seedlings during germination and classified them as highly tolerant, tolerant, sensitive and highly sensitive. From this primary screening, ten cultivars that showed differential responses to dehydration stress were selected to understand the biochemical and physiological basis of stress tolerance mechanisms. The highly tolerant cultivars showed lower levels of lipid peroxidation, less membrane damage, increased levels of antioxidants, enzymes like catalase, ascorbate peroxidase, glutathione reductase activities, and maintained higher relative water content in comparison to sensitive cultivars, indicating better protection mechanism operating in tolerant cultivars. Correspondingly, highly tolerant cultivars exhibited more accumulation of proline and less H2O2 content across different time points of polyethylene glycol treatments in comparison to sensitive ones. The above biochemical and physiological parameters were further validated through northern analysis of catalase (CAT1) gene, that showed differential expression patterns in tolerant and sensitive cultivars largely in confirmation with the biochemical and physiological analyses. Our study positively correlates the differences in the redox status and antioxidant defense system between tolerant and sensitive cultivars for the establishment of wheat seedlings in typical dehydration conditions.Item PROTEIN L-ISOASPARTYL METHYLTRANSFERASE1 (CaPIMT1) from chickpea mitigates oxidative stress-induced growth inhibition of Escherichia coli(Springer, 2010) Verma, Pooja; Singh, Ajeet; Kaur, Harmeet; Majee, ManojPROTEIN L-ISOASPARTYL METHYLTRANSFERASE (PIMT) repairs deleterious L-isoaspartyl residues synthesized spontaneously in proteins due to aging or stressful environments and is widespread in living organisms including plants. Even though PIMT activity has been detected from various plant sources, detailed studies are limited to a few species. Our present study on a chickpea (Cicer arietinum) PIMT reveals that apart from seed, PIMT activity is present in other organs and noticeably enhanced during stressful conditions. Using degenerate oligonucleotides and RACE strategy, a full length cDNA (CaPIMT1) was cloned and sequenced. The cDNA is 920 bp in length and contains only one open reading frame of 690 bp encoding 229 amino acids. Genomic structure reveals that the CaPIMT1 gene spans about 2,050 bp in length and contains four exons and three introns. By quantitative real-time RT-PCR, we demonstrate that the transcript of CaPIMT1 is distributed across the organs with maximum levels in seed and is also enhanced under various environmental stress conditions. Purified bacterially expressed protein is further characterized for its catalytic properties. The activity is found to be elevated towards high temperature and pH conditions. Escherichia coli expressing CaPIMT1 show greater tolerance to oxidative stress than E. coli without CaPIMT1. Taken together, our results suggest that PIMT from chickpea shows a distinct pattern of expression and may have a specific role in stress adaptation apart from seed.