Dr Rohit Joshi | IHBT (CSIR) (original) (raw)
Papers by Dr Rohit Joshi
Nitrogen is an essential macronutrient for the plants and fertilizer N-use effi ciency is becomin... more Nitrogen is an essential macronutrient for the plants and fertilizer N-use effi ciency is becoming an increasing economic and environmental concern. The nutrient stress conditions of N defi ciency and N excess may get exacerbated by other abiotic stresses, which in turn are likely to be worsened by climate change. Exploring their interrelationships is being increasingly facilitated by the growing knowledge of the genome-wide N response as well as other abiotic stress responses in model plants. Nitrate and its more reduced forms are not only sources of plant N nutrition but also signals that govern their own uptake; N, C, and redox metabolism; and hormonal and other organism-wide responses. The signaling mechanisms involved in N response or response to N stress or N-use effi ciency are currently far less well understood than those in other abiotic stresses. The purpose of this review is to provide an overview of the current state of knowledge on normal N response and response to N stress, as well as their interrelationships with other abiotic stresses.
Agriculture
Plant growth and productivity is negatively affected by several abiotic stresses. To overcome the... more Plant growth and productivity is negatively affected by several abiotic stresses. To overcome the antagonistic effect of a changing environment, plants have evolved several modifications at the physiological as well as molecular levels. Besides being a vital organ for a plant’s nutrient uptake, roots also plays a significant role in abiotic stress regulation. This review provides insight into changing Root System Architecture (RSA) under varying environmental stimuli using high-throughput omics technologies. Several next-generation and high-throughput omics technologies, such as phenomics, genomics, transcriptomics, proteomics, and metabolomics, will help in the analysis of the response of root architectural traits under climatic vagaries and their impact on crop yield. Various phenotypic technologies have been implied for the identification of diverse root traits in the field as well as laboratory conditions, such as root-box pinboards, rhizotrons, shovelomics, ground-penetrating r...
Antioxidants
Nardostachys jatamansi is a critically endangered medicinal plant and endemic to the Himalayas, h... more Nardostachys jatamansi is a critically endangered medicinal plant and endemic to the Himalayas, having high commercial demand globally. The accumulation of various secondary metabolites in its shoots and roots with antioxidant potential are well-documented in traditional as well as modern medicine systems. In the present study, we first attempted to investigate the impact of citrate (−ve charge, 11.1 ± 1.9 nm) and CTAB (+ve charge, 19.5 ± 3.2 nm) coated gold nanoparticles (AuNPs) on the in vitro proliferation and antioxidant activities of N. jatamansi. Both the nanoparticles differentially affected the morphological and biochemical parameters, chlorophyll content, internal hormone concentration, and antioxidant activities in a concentration-dependent (10–100 µM) manner. Vigorous shooting was observed in half strength MS medium supplemented with IAA (1 mg/L) with 60 µM citrate-AuNPs (46.4 ± 3.7 mm) and 40 µM CTAB-AuNPs (42.2 ± 3.2 mm). Similarly, the maximum number of roots (5.00 ± 0...
Sustainable Development and Biodiversity, 2019
Plant functional genomics has revolutionized not only the methodologies for identification and el... more Plant functional genomics has revolutionized not only the methodologies for identification and elucidation of key genes’ function but also in designing strategies for improving tolerance towards abiotic stresses. Leveraging various approaches has demonstrated the robustness and versatility in their application to study gene/genome function and engineering abiotic stress tolerance in plants. With the emergence of novel high throughput technologies in this area, functional genomics can contribute immensely in understanding the gene regulatory networks operating under stress, thereby benefiting crop improvement programs. This chapter provides recent findings in the field of functional genomics, thus offering several efficacious methodologies such as next generation sequencing, genome-wide hybridization, gene-inactivation and genome-editing-based strategies in addition to metabolite analysis for discovery as well as validation of the candidate genes. Further, methodologies such as gene expression microarrays, insertional mutagenesis, map-based cloning and various genomic-assisted methods are evaluated critically and discussed in the light of integration of the information obtained through functional genomics with practical application in crop breeding.
International Journal of Bioassays, 2014
The aim of the study was to determine the effect of rhododendron flower juice on the bioavailabil... more The aim of the study was to determine the effect of rhododendron flower juice on the bioavailability of Amlodipine in rats. This study was carried out in rats as a parallel design study. After the analysis of blood samples, it has been concluded that a component (s) of rhododendron flower juice inhibits the CYP3A4 mediated metabolism of Amlodipine. AUC was determined with the help of Trapezoidal rule. C max and T max were determined from the area under the plasma concentration-time curve. Statistical analysis was performed on the data obtained from both the group of rats. One way Analysis of Variance (ANOVA) from which Tukey-Kramer Multiple Comparisons Test was applied to the data obtained. This test compared all the parameters such as AUC, C max and T max without flower juice and after giving flower juice and the standard deviation of AUC of amlodipine with and without juice was found to be 14.25 and 10.44 respectively. AUC of the amlodipine after giving rhododendron flower juice...
Physiology and Molecular Biology of Plants, 2021
Methylglyoxal (MG) is ubiquitously produced in all living organisms as a byproduct of glycolysis,... more Methylglyoxal (MG) is ubiquitously produced in all living organisms as a byproduct of glycolysis, higher levels of which are cytotoxic, leading to oxidative stress and apoptosis in the living systems. Though its generation is spontaneous but its detoxification involves glyoxalase pathway genes. Based on this understanding, the present study describes the possible role of MG as a novel non-antibiotic-based selection agent in rice. Further, by metabolizing MG, the glyoxalase pathway genes viz. glyoxalase I (GLYI) and glyoxalase II (GLYII), may serve as selection markers. Therefore, herein, transgenic rice harboring GLYI-GLYII genes (as selection markers) were developed and the effect of MG as a selection agent was assessed. The 3 mM MG concentration was observed as optimum for the selection of transformed calli, allowing efficient callus induction and proliferation along with high regeneration frequency (55 ± 2%) of the transgenic calli. Since the transformed calli exhibited constitutively higher activity of GLYI and GLYII enzymes compared to the wild type calli, the rise in MG levels was restricted even upon exogenous addition of MG during the selection process, resulting in efficient selection of the transformed calli. Therefore, MG-based selection method is a useful and efficient system for selection of transformed plants without significantly compromising the transformation efficiency. Further, this MG-based selection system is bio-safe and can pave way towards better public acceptance of transgenic plants.
Saudi Pharmaceutical Journal, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Plant Molecular Biology Reporter, 2020
In plants, reactive oxygen species accumulate to a toxic level under various abiotic stresses. Ma... more In plants, reactive oxygen species accumulate to a toxic level under various abiotic stresses. Many antioxidant defense systems require NADPH as a principal reducing energy equivalent. However, the source of NADPH and the molecular mechanisms associated with the maintenance of cytoplasmic redox balance are still unknown. The present study describes Vigna NADH kinase (VlNADHK), an enzyme involved in NADPH synthesis and prefers NADH as a diphospho-nicotinamide nucleotide donor. We analyzed the enzymatic activity of a putative cytoplasmic NADH kinase during waterlogging in contrasting mung bean genotypes Vigna luteola (tolerant) and Vigna radiata cv. T44 (susceptible) under pot-culture condition. The tolerant cultivar showed higher enzymatic activity under waterlogging as well as after recovery. Similarly, the transcript level of waterlogginginduced NADHK expression was also studied and found to be upregulated in response to waterlogging in the roots of V. luteola and T44. PCR amplicons of partial and full-length sequences were cloned and sequenced from V. luteola. To the best of our knowledge, this is the first time an ATP-dependent NADH kinase gene has been recognized as a component of waterlogging stress tolerance in legumes. Our study indicated that this cytoplasmic NADH kinase is a primary source of the cytosolic NADPH and might have a role in waterlogging tolerance in legumes.
Current Plant Biology, 2018
All the irrigated rice systems are currently facing a worldwide challenge for producing higher yi... more All the irrigated rice systems are currently facing a worldwide challenge for producing higher yield with lower water availability. Aerobic rice is considered to be promising for rice production under water constrained environments where it can be grown under non-flooded and unsaturated soil. All practices for aerobic rice cultivation must start by first identifying promising rice varieties that are expected to produce higher grain yield under such conditions. Therefore, we conducted a field experiment with an experimental design of split-plot in the Tarai region of the Western Himalayas, India, in two irrigation regimes i.e., of continuous flooding and of aerobic condition, using four high-yielding rice genotypes: DRRH-2, PA6444, KRH-2 and Jaya. A grain yield of 743 to 910 g/m 2 was obtained on a typical freely draining soil i.e., under aerobic conditions. Further, DRRH-2 showed enhanced panicle number, spikelet number, filled grain number under aerobic conditions, resulting in the higher grain yield of 910 g m/m 2. We conclude from our studies that the higher productivity of rice depends upon the improved sink capacity (grain number x grain weight) of the genotype, and that this acts as a major factor limiting yield potential under aerobic and flooded conditions.
Plant biotechnology journal, Jan 31, 2018
Actin depolymerizing factors (ADFs) maintain the cellular actin network dynamics by regulating se... more Actin depolymerizing factors (ADFs) maintain the cellular actin network dynamics by regulating severing and disassembly of actin filaments in response to environmental cues. An ADF isolated from a monocot halophyte, Spartina alterniflora (SaADF2) imparted significantly higher level of drought and salinity tolerance when expressed in rice than its rice homologue OsADF2. SaADF2 differs from OsADF2 by a few amino acid residues, including a substitution in the regulatory phosphorylation site serine-6, which accounted for its weak interaction with OsCDPK6 (calcium dependent protein kinase), thus resulting in an increased efficacy of SaADF2 and enhanced cellular actin dynamics. SaADF2 overexpression preserved the actin filament organization better in rice protoplasts under desiccation stress. The predicted tertiary structure of SaADF2 showed a longer F-loop than OsADF2 that could have contributed to higher actin-binding affinity and rapid F-actin depolymerization in vitro by SaADF2. Rice ...
Methods in molecular biology (Clifton, N.J.), 2017
Salinity and drought are interconnected, causing phenotypic, physiological, biochemical, and mole... more Salinity and drought are interconnected, causing phenotypic, physiological, biochemical, and molecular changes in a cell. These stresses are the major factors adversely affecting growth and productivity in cereals. Genetic engineering methods have advanced to enable development of genotypes with improved salinity and drought tolerance. The resulting transgenic plant produces a group of progenies which includes moderate to high-stress tolerant transgenic lines. Development of reproducible screening methods to identify high-stress tolerant germplasm under laboratory, greenhouse, or field conditions is must. Further, field level demonstration of improved phenotypes and yield under salinity and drought stress conditions is both challenging and expensive. Fast and efficient screening techniques that could be used to screen transgenic lines under greenhouse conditions, for salt and drought stress tolerance, may contribute toward the identification of promising lines for field conditions. ...
Plant, cell & environment, Jan 24, 2017
Cytokinins play a significant role in determining grain yield in plants. Cytokinin oxidases catal... more Cytokinins play a significant role in determining grain yield in plants. Cytokinin oxidases catalyze irreversible degradation of cytokinins and hence modulate cellular cytokinin levels. Here, we studied the role of an inflorescence meristem-specific rice cytokinin oxidase - OsCKX2, in reducing yield penalty under salinity stress conditions. We utilized an RNAi-based approach to study the function of OsCKX2 in maintaining grain yield under salinity stress condition. Ultra-performance liquid chromatography (UPLC)-based estimation revealed a significant increase in cytokinins in the inflorescence meristem of OsCKX2-knockdown plants. To determine if there exists, a correlation between OsCKX2 levels and yield under salinity stress condition, we assessed the growth, physiology and grain yield of OsCKX2-knockdown plants vis-à-vis the wild-type. OsCKX2-knockdown plants showed better vegetative growth, higher relative water content as well as photosynthetic efficiency, and reduced electrolyt...
Plant Cell Reports, 2015
Key message Our results indicate that OsPGK2a-P gene is differentially regulated in contrasting r... more Key message Our results indicate that OsPGK2a-P gene is differentially regulated in contrasting rice cultivars under stress and its overexpression confers salt stress tolerance in transgenic tobacco. Abstract Phosphoglycerate kinase (PGK; EC = 2.7.2.3) plays a major role for ATP production during glycolysis and 1, 3-bisphosphoglycerate production to participate in the Calvin cycle for carbon fixation in plants. Whole genome analysis of rice reveals the presence of four PGK genes (OsPgks) on different chromosomes. Comparative expression analysis of OsPgks in rice revealed highest level of transcripts for OsPgk2 at most of its developmental stages. Detailed characterization of OsPgk2 transcript and protein showed that it is strongly induced by salinity stress in two contrasting genotypes of rice, i.e., cv IR64 (salt sensitive) and landrace Pokkali (salt tolerant). Ectopic expression of OsPgk2a-P (isolated from Pokkali) in transgenic tobacco improved its salinity stress tolerance by higher chlorophyll retention and enhanced proline accumulation, besides maintaining better ion homeostasis. Ectopically expressing OsPgk2a-P transgenic tobacco plants showed tall phenotype with more number of pods than wild-type plants. Therefore, OsPgk2a-P appears to be a potential candidate for increasing salinity stress tolerance and enhanced yield in crop plants.
Salt and drought stresses negatively affect rice yield. The magnitude of yield reduction depends ... more Salt and drought stresses negatively affect rice yield. The magnitude of yield reduction depends on the genotype and developmental stage of the plant, and the severity of the stress. While natural variations for stress tolerance exist in the primary and secondary gene pool of rice, conventional breeding to develop salt and drought tolerant varieties has been slow and less successful due to the complexity and low heritability of stress tolerance traits. Extremophiles, such as halophytes, adapt to abiotic stresses by physiological and biochemical adjustments through coordinate regulation and expression of a cascade of genes. Halophytes are of interest to translate their stress adaptation machinery into crop plants. Based on the concept that monocot halophytes are ideal for translational studies for cereals, we profiled the root and leaf transcriptome of Spartina alterniflora (smooth cordgrass), a Louisiana native monocot halophyte, which can withstand salinity up to double the strengt...
ABSTRACT Rice (Oryza sativa L.) is one of the most important staple food crops in the world. It i... more ABSTRACT Rice (Oryza sativa L.) is one of the most important staple food crops in the world. It is estimated that demand for rice in 2010 will be 100 million tonnes and in 2025, it will be 140 million tonnes. Rice consumes around 90% of total irrigation water amongst all crops. Traditionally around 3000-5000 liters of water is required to grow one kilogram of rice. Due to the reducing availability of water for agriculture, higher emission of green house gases (NO2 and CH4) from irrigated low land rice cultivation and their deleterious effect on global climate, “Aerobic rice” has been paid more and more attention because of its great potential of water saving and high productivity. This high-input system is replacing lowland rice in areas where water scarcity makes lowland rice impossible. Aerobic rice cultivation has the potential to improve the water productivity, production efficiency and helps in maintaining the soil structure and its microclimate. The present study focuses on comparative parameters proposing suitable criteria model and assessing potential of aerobic rice for the cost effective (labour, seed etc.) cultivation. Indirect selection for deep-rooted rice varieties through shoot-related traits i.e., shoot dry weight followed by plant height helps in identifying drought tolerant lines. However, further research is required to develop and categorize suitable aerobic rice varieties for different rice ecosystems.
ABSTRACT Present investigation was carried out with an objective to study the in vitro genotypic ... more ABSTRACT Present investigation was carried out with an objective to study the in vitro genotypic response of three aromatic rice cultivars, viz. Pusa Basmati 1, Pant Sugandh Dhan 17, Taraori Basmati and one non aromatic Narendra 359 to water deficit stress using mature embryos as explants. The effect of water deficit was induced by sub-culturing calli on Murashige and Skoog medium supplemented with different concentrations of polyethylene glycol (PEG)-6000. Total protein content was found to be increased with increasing concentration of PEG-6000 in the medium. SDS-PAGE of somaclones showed over expression of polypeptides ranged from 29 - 205 kDa under higher stress levels, which in turn suggested that many proteins are specifically altered de novo under water stress as a part of the adaptive mechanism. Rice cultivar, Narendra 359 showed best response in terms of chlorophyll and higher total protein content along with activation of few specific polypeptides under water stress and thus, proved to be drought tolerant. The protein profiling was complemented by analyzing the genetic diversity of these varieties with random amplified polymorphic DNA (RAPD). RAPD profiles from the micro propagated plants showed polymorphism with similarity ranging from 0.46 to 0.76.
Studies were conducted on 47 bold grain rice genotypes with two locally recommended high yielding... more Studies were conducted on 47 bold grain rice genotypes with two locally recommended high yielding check varieties namely Ranjit and Monohar Sali of Barak Valley, Assam to assess the genetic variability, correlation and coheritability for five nutritional and seven cooking quality characters. High heritability associated with high genetic advance was found in the cooking quality traits viz. alkali digestion value, cooked rice kernel length, cooked rice kernel lengthwise elongation ratio and water absorption (%); in the nutritional character total soluble sugar content showed high heritability and genetic advance. These characters were predominantly governed by additive gene action. High heritability along with moderate genetic advance was observed in the cooking quality characters gel consistency, cooked rice kernel breadth and cooked rice kernel breadth wise elongation ratio and in the nutritional characters like total soluble protein content and amylose content. Lastly, high heritability with low genetic advance was recorded for starch content and amylopectin content. This indicated that these characters were mostly governed by non-additive gene action (dominance and epistasis). The genotypic correlation coefficient was found to be higher than the corresponding phenotypic correlation coefficient. This indicates a strong inherent association among total soluble protein content and other nutritional and cooking quality traits. The highest positive coheritability of cooked kernel breadth was found with cooked kernel breadth wise elongation ratio (87.93%) followed by water absorption (60.25%).
The objective of this study was to examine the role of nitrate reductase, nitric oxide and nonsym... more The objective of this study was to examine the role of nitrate reductase, nitric oxide and nonsymbiotic hemoglobin in imparting waterlogging tolerance in mung bean genotypes. Experiment was conducted with five cultivated mung bean [Vigna radiata (L.) Wilczek] genotypes viz., T 44, MH 96-1 (relatively tolerant), and Pusa Baisakhi, MH 1K-24 and PS 10 (susceptible) under pot-culture condition. Waterlogging induced reduction in relative water content, chlorophyll content and membrane stability index was comparatively less in tolerant genotypes T 44, MH 96-1 than in Pusa Baisakhi, MH 1K-24 and PS 10. The nitric oxide (NO) production activity increased up to 6 days of waterlogging treatment in all the genotypes, however T 44, MH 96-1 maintained more than double NO content than Pusa Baisakhi, MH 1K-24 and PS 10. Increase in nitrate reductase (NR) activity under waterlogging was observed up to 6-days of treatment in all the genotypes, and T 44, MH 96-1 maintained significantly higher NR act...
Nitrogen is an essential macronutrient for the plants and fertilizer N-use effi ciency is becomin... more Nitrogen is an essential macronutrient for the plants and fertilizer N-use effi ciency is becoming an increasing economic and environmental concern. The nutrient stress conditions of N defi ciency and N excess may get exacerbated by other abiotic stresses, which in turn are likely to be worsened by climate change. Exploring their interrelationships is being increasingly facilitated by the growing knowledge of the genome-wide N response as well as other abiotic stress responses in model plants. Nitrate and its more reduced forms are not only sources of plant N nutrition but also signals that govern their own uptake; N, C, and redox metabolism; and hormonal and other organism-wide responses. The signaling mechanisms involved in N response or response to N stress or N-use effi ciency are currently far less well understood than those in other abiotic stresses. The purpose of this review is to provide an overview of the current state of knowledge on normal N response and response to N stress, as well as their interrelationships with other abiotic stresses.
Agriculture
Plant growth and productivity is negatively affected by several abiotic stresses. To overcome the... more Plant growth and productivity is negatively affected by several abiotic stresses. To overcome the antagonistic effect of a changing environment, plants have evolved several modifications at the physiological as well as molecular levels. Besides being a vital organ for a plant’s nutrient uptake, roots also plays a significant role in abiotic stress regulation. This review provides insight into changing Root System Architecture (RSA) under varying environmental stimuli using high-throughput omics technologies. Several next-generation and high-throughput omics technologies, such as phenomics, genomics, transcriptomics, proteomics, and metabolomics, will help in the analysis of the response of root architectural traits under climatic vagaries and their impact on crop yield. Various phenotypic technologies have been implied for the identification of diverse root traits in the field as well as laboratory conditions, such as root-box pinboards, rhizotrons, shovelomics, ground-penetrating r...
Antioxidants
Nardostachys jatamansi is a critically endangered medicinal plant and endemic to the Himalayas, h... more Nardostachys jatamansi is a critically endangered medicinal plant and endemic to the Himalayas, having high commercial demand globally. The accumulation of various secondary metabolites in its shoots and roots with antioxidant potential are well-documented in traditional as well as modern medicine systems. In the present study, we first attempted to investigate the impact of citrate (−ve charge, 11.1 ± 1.9 nm) and CTAB (+ve charge, 19.5 ± 3.2 nm) coated gold nanoparticles (AuNPs) on the in vitro proliferation and antioxidant activities of N. jatamansi. Both the nanoparticles differentially affected the morphological and biochemical parameters, chlorophyll content, internal hormone concentration, and antioxidant activities in a concentration-dependent (10–100 µM) manner. Vigorous shooting was observed in half strength MS medium supplemented with IAA (1 mg/L) with 60 µM citrate-AuNPs (46.4 ± 3.7 mm) and 40 µM CTAB-AuNPs (42.2 ± 3.2 mm). Similarly, the maximum number of roots (5.00 ± 0...
Sustainable Development and Biodiversity, 2019
Plant functional genomics has revolutionized not only the methodologies for identification and el... more Plant functional genomics has revolutionized not only the methodologies for identification and elucidation of key genes’ function but also in designing strategies for improving tolerance towards abiotic stresses. Leveraging various approaches has demonstrated the robustness and versatility in their application to study gene/genome function and engineering abiotic stress tolerance in plants. With the emergence of novel high throughput technologies in this area, functional genomics can contribute immensely in understanding the gene regulatory networks operating under stress, thereby benefiting crop improvement programs. This chapter provides recent findings in the field of functional genomics, thus offering several efficacious methodologies such as next generation sequencing, genome-wide hybridization, gene-inactivation and genome-editing-based strategies in addition to metabolite analysis for discovery as well as validation of the candidate genes. Further, methodologies such as gene expression microarrays, insertional mutagenesis, map-based cloning and various genomic-assisted methods are evaluated critically and discussed in the light of integration of the information obtained through functional genomics with practical application in crop breeding.
International Journal of Bioassays, 2014
The aim of the study was to determine the effect of rhododendron flower juice on the bioavailabil... more The aim of the study was to determine the effect of rhododendron flower juice on the bioavailability of Amlodipine in rats. This study was carried out in rats as a parallel design study. After the analysis of blood samples, it has been concluded that a component (s) of rhododendron flower juice inhibits the CYP3A4 mediated metabolism of Amlodipine. AUC was determined with the help of Trapezoidal rule. C max and T max were determined from the area under the plasma concentration-time curve. Statistical analysis was performed on the data obtained from both the group of rats. One way Analysis of Variance (ANOVA) from which Tukey-Kramer Multiple Comparisons Test was applied to the data obtained. This test compared all the parameters such as AUC, C max and T max without flower juice and after giving flower juice and the standard deviation of AUC of amlodipine with and without juice was found to be 14.25 and 10.44 respectively. AUC of the amlodipine after giving rhododendron flower juice...
Physiology and Molecular Biology of Plants, 2021
Methylglyoxal (MG) is ubiquitously produced in all living organisms as a byproduct of glycolysis,... more Methylglyoxal (MG) is ubiquitously produced in all living organisms as a byproduct of glycolysis, higher levels of which are cytotoxic, leading to oxidative stress and apoptosis in the living systems. Though its generation is spontaneous but its detoxification involves glyoxalase pathway genes. Based on this understanding, the present study describes the possible role of MG as a novel non-antibiotic-based selection agent in rice. Further, by metabolizing MG, the glyoxalase pathway genes viz. glyoxalase I (GLYI) and glyoxalase II (GLYII), may serve as selection markers. Therefore, herein, transgenic rice harboring GLYI-GLYII genes (as selection markers) were developed and the effect of MG as a selection agent was assessed. The 3 mM MG concentration was observed as optimum for the selection of transformed calli, allowing efficient callus induction and proliferation along with high regeneration frequency (55 ± 2%) of the transgenic calli. Since the transformed calli exhibited constitutively higher activity of GLYI and GLYII enzymes compared to the wild type calli, the rise in MG levels was restricted even upon exogenous addition of MG during the selection process, resulting in efficient selection of the transformed calli. Therefore, MG-based selection method is a useful and efficient system for selection of transformed plants without significantly compromising the transformation efficiency. Further, this MG-based selection system is bio-safe and can pave way towards better public acceptance of transgenic plants.
Saudi Pharmaceutical Journal, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Plant Molecular Biology Reporter, 2020
In plants, reactive oxygen species accumulate to a toxic level under various abiotic stresses. Ma... more In plants, reactive oxygen species accumulate to a toxic level under various abiotic stresses. Many antioxidant defense systems require NADPH as a principal reducing energy equivalent. However, the source of NADPH and the molecular mechanisms associated with the maintenance of cytoplasmic redox balance are still unknown. The present study describes Vigna NADH kinase (VlNADHK), an enzyme involved in NADPH synthesis and prefers NADH as a diphospho-nicotinamide nucleotide donor. We analyzed the enzymatic activity of a putative cytoplasmic NADH kinase during waterlogging in contrasting mung bean genotypes Vigna luteola (tolerant) and Vigna radiata cv. T44 (susceptible) under pot-culture condition. The tolerant cultivar showed higher enzymatic activity under waterlogging as well as after recovery. Similarly, the transcript level of waterlogginginduced NADHK expression was also studied and found to be upregulated in response to waterlogging in the roots of V. luteola and T44. PCR amplicons of partial and full-length sequences were cloned and sequenced from V. luteola. To the best of our knowledge, this is the first time an ATP-dependent NADH kinase gene has been recognized as a component of waterlogging stress tolerance in legumes. Our study indicated that this cytoplasmic NADH kinase is a primary source of the cytosolic NADPH and might have a role in waterlogging tolerance in legumes.
Current Plant Biology, 2018
All the irrigated rice systems are currently facing a worldwide challenge for producing higher yi... more All the irrigated rice systems are currently facing a worldwide challenge for producing higher yield with lower water availability. Aerobic rice is considered to be promising for rice production under water constrained environments where it can be grown under non-flooded and unsaturated soil. All practices for aerobic rice cultivation must start by first identifying promising rice varieties that are expected to produce higher grain yield under such conditions. Therefore, we conducted a field experiment with an experimental design of split-plot in the Tarai region of the Western Himalayas, India, in two irrigation regimes i.e., of continuous flooding and of aerobic condition, using four high-yielding rice genotypes: DRRH-2, PA6444, KRH-2 and Jaya. A grain yield of 743 to 910 g/m 2 was obtained on a typical freely draining soil i.e., under aerobic conditions. Further, DRRH-2 showed enhanced panicle number, spikelet number, filled grain number under aerobic conditions, resulting in the higher grain yield of 910 g m/m 2. We conclude from our studies that the higher productivity of rice depends upon the improved sink capacity (grain number x grain weight) of the genotype, and that this acts as a major factor limiting yield potential under aerobic and flooded conditions.
Plant biotechnology journal, Jan 31, 2018
Actin depolymerizing factors (ADFs) maintain the cellular actin network dynamics by regulating se... more Actin depolymerizing factors (ADFs) maintain the cellular actin network dynamics by regulating severing and disassembly of actin filaments in response to environmental cues. An ADF isolated from a monocot halophyte, Spartina alterniflora (SaADF2) imparted significantly higher level of drought and salinity tolerance when expressed in rice than its rice homologue OsADF2. SaADF2 differs from OsADF2 by a few amino acid residues, including a substitution in the regulatory phosphorylation site serine-6, which accounted for its weak interaction with OsCDPK6 (calcium dependent protein kinase), thus resulting in an increased efficacy of SaADF2 and enhanced cellular actin dynamics. SaADF2 overexpression preserved the actin filament organization better in rice protoplasts under desiccation stress. The predicted tertiary structure of SaADF2 showed a longer F-loop than OsADF2 that could have contributed to higher actin-binding affinity and rapid F-actin depolymerization in vitro by SaADF2. Rice ...
Methods in molecular biology (Clifton, N.J.), 2017
Salinity and drought are interconnected, causing phenotypic, physiological, biochemical, and mole... more Salinity and drought are interconnected, causing phenotypic, physiological, biochemical, and molecular changes in a cell. These stresses are the major factors adversely affecting growth and productivity in cereals. Genetic engineering methods have advanced to enable development of genotypes with improved salinity and drought tolerance. The resulting transgenic plant produces a group of progenies which includes moderate to high-stress tolerant transgenic lines. Development of reproducible screening methods to identify high-stress tolerant germplasm under laboratory, greenhouse, or field conditions is must. Further, field level demonstration of improved phenotypes and yield under salinity and drought stress conditions is both challenging and expensive. Fast and efficient screening techniques that could be used to screen transgenic lines under greenhouse conditions, for salt and drought stress tolerance, may contribute toward the identification of promising lines for field conditions. ...
Plant, cell & environment, Jan 24, 2017
Cytokinins play a significant role in determining grain yield in plants. Cytokinin oxidases catal... more Cytokinins play a significant role in determining grain yield in plants. Cytokinin oxidases catalyze irreversible degradation of cytokinins and hence modulate cellular cytokinin levels. Here, we studied the role of an inflorescence meristem-specific rice cytokinin oxidase - OsCKX2, in reducing yield penalty under salinity stress conditions. We utilized an RNAi-based approach to study the function of OsCKX2 in maintaining grain yield under salinity stress condition. Ultra-performance liquid chromatography (UPLC)-based estimation revealed a significant increase in cytokinins in the inflorescence meristem of OsCKX2-knockdown plants. To determine if there exists, a correlation between OsCKX2 levels and yield under salinity stress condition, we assessed the growth, physiology and grain yield of OsCKX2-knockdown plants vis-à-vis the wild-type. OsCKX2-knockdown plants showed better vegetative growth, higher relative water content as well as photosynthetic efficiency, and reduced electrolyt...
Plant Cell Reports, 2015
Key message Our results indicate that OsPGK2a-P gene is differentially regulated in contrasting r... more Key message Our results indicate that OsPGK2a-P gene is differentially regulated in contrasting rice cultivars under stress and its overexpression confers salt stress tolerance in transgenic tobacco. Abstract Phosphoglycerate kinase (PGK; EC = 2.7.2.3) plays a major role for ATP production during glycolysis and 1, 3-bisphosphoglycerate production to participate in the Calvin cycle for carbon fixation in plants. Whole genome analysis of rice reveals the presence of four PGK genes (OsPgks) on different chromosomes. Comparative expression analysis of OsPgks in rice revealed highest level of transcripts for OsPgk2 at most of its developmental stages. Detailed characterization of OsPgk2 transcript and protein showed that it is strongly induced by salinity stress in two contrasting genotypes of rice, i.e., cv IR64 (salt sensitive) and landrace Pokkali (salt tolerant). Ectopic expression of OsPgk2a-P (isolated from Pokkali) in transgenic tobacco improved its salinity stress tolerance by higher chlorophyll retention and enhanced proline accumulation, besides maintaining better ion homeostasis. Ectopically expressing OsPgk2a-P transgenic tobacco plants showed tall phenotype with more number of pods than wild-type plants. Therefore, OsPgk2a-P appears to be a potential candidate for increasing salinity stress tolerance and enhanced yield in crop plants.
Salt and drought stresses negatively affect rice yield. The magnitude of yield reduction depends ... more Salt and drought stresses negatively affect rice yield. The magnitude of yield reduction depends on the genotype and developmental stage of the plant, and the severity of the stress. While natural variations for stress tolerance exist in the primary and secondary gene pool of rice, conventional breeding to develop salt and drought tolerant varieties has been slow and less successful due to the complexity and low heritability of stress tolerance traits. Extremophiles, such as halophytes, adapt to abiotic stresses by physiological and biochemical adjustments through coordinate regulation and expression of a cascade of genes. Halophytes are of interest to translate their stress adaptation machinery into crop plants. Based on the concept that monocot halophytes are ideal for translational studies for cereals, we profiled the root and leaf transcriptome of Spartina alterniflora (smooth cordgrass), a Louisiana native monocot halophyte, which can withstand salinity up to double the strengt...
ABSTRACT Rice (Oryza sativa L.) is one of the most important staple food crops in the world. It i... more ABSTRACT Rice (Oryza sativa L.) is one of the most important staple food crops in the world. It is estimated that demand for rice in 2010 will be 100 million tonnes and in 2025, it will be 140 million tonnes. Rice consumes around 90% of total irrigation water amongst all crops. Traditionally around 3000-5000 liters of water is required to grow one kilogram of rice. Due to the reducing availability of water for agriculture, higher emission of green house gases (NO2 and CH4) from irrigated low land rice cultivation and their deleterious effect on global climate, “Aerobic rice” has been paid more and more attention because of its great potential of water saving and high productivity. This high-input system is replacing lowland rice in areas where water scarcity makes lowland rice impossible. Aerobic rice cultivation has the potential to improve the water productivity, production efficiency and helps in maintaining the soil structure and its microclimate. The present study focuses on comparative parameters proposing suitable criteria model and assessing potential of aerobic rice for the cost effective (labour, seed etc.) cultivation. Indirect selection for deep-rooted rice varieties through shoot-related traits i.e., shoot dry weight followed by plant height helps in identifying drought tolerant lines. However, further research is required to develop and categorize suitable aerobic rice varieties for different rice ecosystems.
ABSTRACT Present investigation was carried out with an objective to study the in vitro genotypic ... more ABSTRACT Present investigation was carried out with an objective to study the in vitro genotypic response of three aromatic rice cultivars, viz. Pusa Basmati 1, Pant Sugandh Dhan 17, Taraori Basmati and one non aromatic Narendra 359 to water deficit stress using mature embryos as explants. The effect of water deficit was induced by sub-culturing calli on Murashige and Skoog medium supplemented with different concentrations of polyethylene glycol (PEG)-6000. Total protein content was found to be increased with increasing concentration of PEG-6000 in the medium. SDS-PAGE of somaclones showed over expression of polypeptides ranged from 29 - 205 kDa under higher stress levels, which in turn suggested that many proteins are specifically altered de novo under water stress as a part of the adaptive mechanism. Rice cultivar, Narendra 359 showed best response in terms of chlorophyll and higher total protein content along with activation of few specific polypeptides under water stress and thus, proved to be drought tolerant. The protein profiling was complemented by analyzing the genetic diversity of these varieties with random amplified polymorphic DNA (RAPD). RAPD profiles from the micro propagated plants showed polymorphism with similarity ranging from 0.46 to 0.76.
Studies were conducted on 47 bold grain rice genotypes with two locally recommended high yielding... more Studies were conducted on 47 bold grain rice genotypes with two locally recommended high yielding check varieties namely Ranjit and Monohar Sali of Barak Valley, Assam to assess the genetic variability, correlation and coheritability for five nutritional and seven cooking quality characters. High heritability associated with high genetic advance was found in the cooking quality traits viz. alkali digestion value, cooked rice kernel length, cooked rice kernel lengthwise elongation ratio and water absorption (%); in the nutritional character total soluble sugar content showed high heritability and genetic advance. These characters were predominantly governed by additive gene action. High heritability along with moderate genetic advance was observed in the cooking quality characters gel consistency, cooked rice kernel breadth and cooked rice kernel breadth wise elongation ratio and in the nutritional characters like total soluble protein content and amylose content. Lastly, high heritability with low genetic advance was recorded for starch content and amylopectin content. This indicated that these characters were mostly governed by non-additive gene action (dominance and epistasis). The genotypic correlation coefficient was found to be higher than the corresponding phenotypic correlation coefficient. This indicates a strong inherent association among total soluble protein content and other nutritional and cooking quality traits. The highest positive coheritability of cooked kernel breadth was found with cooked kernel breadth wise elongation ratio (87.93%) followed by water absorption (60.25%).
The objective of this study was to examine the role of nitrate reductase, nitric oxide and nonsym... more The objective of this study was to examine the role of nitrate reductase, nitric oxide and nonsymbiotic hemoglobin in imparting waterlogging tolerance in mung bean genotypes. Experiment was conducted with five cultivated mung bean [Vigna radiata (L.) Wilczek] genotypes viz., T 44, MH 96-1 (relatively tolerant), and Pusa Baisakhi, MH 1K-24 and PS 10 (susceptible) under pot-culture condition. Waterlogging induced reduction in relative water content, chlorophyll content and membrane stability index was comparatively less in tolerant genotypes T 44, MH 96-1 than in Pusa Baisakhi, MH 1K-24 and PS 10. The nitric oxide (NO) production activity increased up to 6 days of waterlogging treatment in all the genotypes, however T 44, MH 96-1 maintained more than double NO content than Pusa Baisakhi, MH 1K-24 and PS 10. Increase in nitrate reductase (NR) activity under waterlogging was observed up to 6-days of treatment in all the genotypes, and T 44, MH 96-1 maintained significantly higher NR act...