Pradeep K Agarwal

Central Salt and Marine Chemicals Research Institute, Baunagar, Gujarāt, India

Are you Pradeep K Agarwal?

Claim your profile

Publications (33)64.13 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The high-affinity potassium transporters (HKT) are highly important for stress tolerance in plants as they uniquely maintain K(+)/Na(+) ratio for their survival and growth. In this study a novel HKT gene AlHKT2;1 was isolated and characterized from salt secreting halophyte, Aeluropus lagopoides. The AlHKT2;1 cDNA comprised of an open reading frame of 1,581 bp, encoding a protein of 526 amino acid residues. It belongs to class II HKTs and showed high homology with other HKT genes. Functional characterization of AlHKT2;1 in both K(+) uptake-deficient (WΔ6) and Na(+)-sensitive yeast mutants (G19) showed the characteristic feature of low-affinity K(+) transporter supporting the growth at >1 mM KCl concentration. The transformed yeast cells showed high sensitivity to NaCl; however, the addition of KCl along with NaCl support the growth of AlHKT2;1 expressing mutant. Ion content analysis of yeast cells with AlHKT2;1 grown in high NaCl medium supplemented with KCl revealed that salt tolerance was correlated with accumulation of K(+) during salt stress. These results suggest that AlHKT2;1 plays an important role in the K(+) uptake during salt stress and in maintaining a high K(+)/Na(+) ratio in the cytosol.
    Molecular biotechnology. 01/2015;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Salicornia brachiata Roxb. (Amaranthaceae) a leaf-less annual succulent halophyte, grows under extremely saline conditions and is an important resource for salt stress responsive genes. Here we report somatic embryogenesis and in vitro plantlet regeneration in S. brachiata for the first time. In vitro-grown seedlings were used as explants and 86.0 ± 1.7 % explants produced embryogenic callus on 0.75 % agar-gelled Murashige and Skoog’s (MS) medium containing 2.0 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-d) in 16 weeks. Somatic embryogenesis was achieved on MS medium supplemented with 0.25 mg l−1 2,4-d. On this medium sustained cell division and growth within the first 8 weeks resulted in the formation of cell aggregates in 73.65 ± 0.44 % cultures producing globular somatic embryos (SEs). Gradually these converted into heart, torpedo and cotyledonary shaped SEs following subsequent 16 weeks subculture on the same medium. Around 35 % SEs germinated on plant growth regulator free MS medium. The somatic seedlings were acclimatized on sterile soil with 40–45 % survival.
    Plant Cell Tissue and Organ Culture 01/2015; 120(1). · 2.61 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The endomembrane system plays an important role during cellular adaptation of the plants with the extracellular environment. The small GTP-binding protein Rab7 located at the vacuolar membrane regulates the vesicle fusion with the vacuole and thereby helps in recycling of the molecules. This is the first report on isolation and characterization of AlRab7 gene from the halophyte plant, Aeluropus that extrudes NaCl through salt glands and grows luxuriantly throughout the year at the Gujarat coast, India. The AlRab7 encodes a protein with 206 amino acids, and a highly conserved effector-binding domain and four nucleotide-binding domains. The in silico analysis predicts the presence of the prenylation site for Rab geranylgeranyltransferase 2 and the Rab escort protein site. The C-terminal two cysteine residues in -XCC sequence are present for membrane attachment. Transcript expression of the AlRab7 gene was differentially regulated by different environmental stimuli such as dehydration, salinity, and hormone abscisic acid (ABA). The recombinant Escherichia coli cells showed improved growth in Luria Bertani medium supplemented with NaCl, KCl, mannitol, ABA, and indole-3-acetic acid. A novel Rab7 interacting partner AlRabring7 was identified by yeast two-hybrid screening.
    DNA and Cell Biology 11/2014; · 1.99 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present invention relates to a product Kappaphycus alvarezii seaweed sap free of Gibberellic acid (GA3) and its method of preparation. Kappaphycus alvarezii seaweed sap is a plant stimulant found to enhance yield and quality of a number of crops. Besides containing many macro- and micro- nutrients, there are many plant growth hormones present in Kappaphycus alvarezii sap. It has been observed that pristine Kappaphycus alvarezii sap and GA3 free sap enhanced grain yield but surprisingly selective removal of GA3 from the pristine sap had profound stimulating effect on total dry above ground biomass yield of maize over and above the pristine sap. Upon seed treatment with GA3 free sap, ?-amylase enzyme activity in the germinating seed of mung bean is found to be increased. The foliar spray of GA3 free sap on tomato plants upregulated disease responsive genes (PR-3 and PR-5) as compared to pristine sap.
    Ref. No: Pub. No.: WO2014167583 (A1), Year: 10/2014
  • Source
    Kapil Gupta, Bhavanath Jha, Pradeep K Agarwal
    [Show abstract] [Hide abstract]
    ABSTRACT: Dehydration-responsive element binding (DREB) transcription factor (TF) plays a key role for abiotic stress tolerance in plants. Earlier, we have published the isolation and characterisation of an A-2-type SbDREB2A TF from an extreme halophyte Salicornia brachiata. The SbDREB2A protein lacks potential proline (P), glutamic acid (E), serine (S) and threonine (T) (PEST) sequence which is known to act as signal peptide for protein degradation. In this study, SbDREB2A TF was over-expressed in tobacco plants without any modification in polypeptide sequence. Transgenic plants showed better seed germination and growth characteristics in both hyperionic and hyperosmotic stresses. Transgenic plants exhibited higher water content, membrane stability and less electrolyte leakage in stress conditions. The transgenic plants accumulated less Na(+) and higher K(+) than wildtype (WT) plants. The transgenic plants revealed higher chlorophyll content, water use efficiency (WUE) and net photosynthesis rate. Transgenics exhibited higher level of proline and low amount of MDA and H2O2 under stress conditions. The real-time PCR of transgenics showed higher expression of downstream heat shock genes (Hsp18, Hsp26 and Hsp70), TFs (AP2 domain containing TF, HSF2 and ZFP), signalling components (PLC3 and Ca (2+) /calmodulin) and dehydrins (ERD10B, ERD10D and LEA5) under different abiotic stress treatments.
    Marine Biotechnology 07/2014; · 3.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Surfactant-induced coagulation of agarose from alkali-treated Gracilaria dura seaweed extract (SE) is reported. The new approach, which was suitable for linear galactans with low sulphate content is an alternative to the traditional energy intensive process of “freeze–thaw” cycles employed for product isolation from the extract. Only nonionic surfactants were effective, and detailed studies were undertaken with octyl phenol ethoxylate (Triton X-100). The coagulated product was successively washed with water and water–isopropyl alcohol (IPA) to yield a fine powder of agarose in 13–15% yield (with respect to dry biomass). The product exhibited excellent properties [sulphate content: 0.2% w/w; degree of electro-endosmosis: 0.13; gel strength: 2200 g cm�2 (1% gel, w/v); and gelling temperature: 35 � 1 �C] essential for demanding molecular biology applications, and the desired gel electrophoretic separation of DNA and RNA was demonstrated. It was further confirmed that there was no degradation of nucleic acids in the gel. The agarose-depleted extract, along with water used for washings, was subjected to reverse osmosis for recovering the surfactant in concentrated form for its subsequent reuse. Energy savings from the improved process were assessed.
    RSC Advances 06/2014; 4:28093–28098. · 3.71 Impact Factor
  • Parinita Agarwal, Mitali Dabi, Pradeep K Agarwal
    [Show abstract] [Hide abstract]
    ABSTRACT: The WRKY family of transcription factors (TFs) play an intricate role in regulating the stress signaling pathways by autoregulation or may be by cross regulation through interaction with other proteins. Although WRKY TFs are considered to be plant specific, however, their presence has been reported from unicellular algae, slime mould, and gymnosperms. We have isolated the JcWRKY cDNA from an important biofuel crop Jatropha curcas growing in the wastelands of India. The JcWRKY gene has an ORF of 693 bp and encodes a 230 amino acids protein with estimated molecular mass of 25.25 kDa. JcWRKY shows close homology to FaWRKY1 and St-WRKY1. The JcWRKY contains seven potential phosphorylation sites, which might be involved in regulating its function. The transcript analysis revealed that the JcWRKY transcript gets upregulated in response to salinity, dehydration, salicylic acid (SA), methyl jasmonate (MeJa), and collar rot fungus Macrophomina. However, maximum expression is observed under SA, highlighting its role in enhancing systemic acquired resistance for disease tolerance. The JcWRKY recombinant protein showed binding to W-box of pathogenesis related-1 (PR-1) and iso1 (encoding isoamylase1) promoters. Overexpression of JcWRKY in Escherichia coli enhanced the growth of cells in NaCl, KCl, mannitol, sorbitol, SA, and MeJa treatments, indicating that it protects and promotes growth under ionic, osmotic, and chemical stresses. The enhancement in growth can be due to the regulation of stress responsive genes. Therefore, it can be used as an important gene for enhancing abiotic and biotic resistance in plants and to facilitate faster growth of E. coli cells under stress conditions for efficient expression.
    DNA and cell biology 04/2014; · 2.28 Impact Factor
  • Parinita Agarwal, Pradeep K Agarwal
    [Show abstract] [Hide abstract]
    ABSTRACT: Pathogenesis related-10 proteins are small proteins with cytosolic localization, conserved three dimensional structures and single intron at 185 bp position. These proteins have a broad spectrum of roles significantly in biotic and abiotic stresses. The RNase activity, ligand binding activity, posttranslational modification (phosphorylation) and phytohormone signaling provide some information into the mechanism of the regulation of PR-10 proteins, however the presence of isoforms makes it difficult to decipher its exact mode of function. The involvement of phosphorylation/dephosphorylation events in its activation is interesting and provides unique and unbiased insights into the complexity of its regulation. Studies on upstream region of different PR-10 genes indicate the presence of cis-acting elements for WRKY, RAVI, bZ1P, ERF, SEBF and Pti4 transcription factors indicating their role in regulating PR-10 promoter. In this review, we discuss in detail the structure and mechanism of regulation of PR-10 proteins.
    Molecular Biology Reports 12/2013; 41(2). · 1.96 Impact Factor
  • Source
    Pradeep K. Agarwal, Narendra Singh Yadav, Bhavanath Jha
    [Show abstract] [Hide abstract]
    ABSTRACT: Abiotic stresses affect adversely the growth and productivity of crops. Among abiotic stresses, salinity is one of the major factors leading to crop losses. According to the UN Food and Agriculture Organization, more than 800 Mha of land is salt-affected worldwide. The problem of soil salinization is becoming more serious due to scanty rainfall, repetitive sea water invasion, heavy utilization of ground water for agricultural and industrial purposes, and degradation of saline parent rock. The area under cultivation is fast getting depleted and becoming unsuitable for agricultural crops. Soil salinity adversely affects plant growth and development, and disturbs intracellular ion homeostasis, resulting in cellular toxicity. Plant adaptation to salinity stress involves a plethora of genes involved in ion transport and compartmentalization (ion homeostasis), compatible solutes/osmolytes, reactive oxygen species, and antioxidant defense mechanism. Transporters are an important group of genes that play a pivotal role in ion homeostasis in plants (Na+/H+ antiporters like SOS1 and NHX1, and proton pump HKT1). Over the last two decades the major studies on the molecular mechanisms of salt tolerance have concentrated on glycophytes; however, only limited studies have been performed on halophytes. Halophytes have a unique genetic makeup that provides an advantage for the study of salt-tolerance mechanisms. Halophytes maintain a low salt concentration inside the cytosol by sequestration in vacuoles or extrusion of Na+ outside the plasma membrane or secretion of salt outside the plant (bladders, salt glands). Since halophytes are very important for the study of salt-tolerance mechanisms, this chapter is focused on the work carried out on transporter genes from halophytes present at the plasma membrane and tonoplast controlling Na+ homeostasis under salinity.
    Climate Change and Plant Abiotic Stress Tolerance, First edited by Narendra Tuteja, Sarvajeet S. Gill, 11/2013: chapter Role of Na +/H + Antiporters in Na + Homeostasis in Halophytic Plants: pages 685-704; Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany.., ISBN: 9783527675265
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present investigation aimed to evaluate the reliability of in vitro propagation methods for elite genotypes of Jatropha curcas L., that maintain genetic integrity of tissue culture (TC) regenerates among two regeneration systems developed through direct shoot bud regeneration using nodal/apical shoot segments (protocol-A) and in vitro-derived leaves (protocol-B) as explants. Random amplified polymorphic DNA (RAPD), intersimple sequence repeat (ISSR), simple sequence repeat (SSR) molecular markers, and flow cytometery (FCM) were employed to evaluate genetic homogeneity in TC-regenerates at different passages of subcultures. RAPD markers showed genetic homogeneity in fifth-generation TC-regenerates of both protocols. ISSR markers showed genetic stability of leaf regenerates (protocol-B) at 10th generation. FCM analysis of TC-regenerates at 10th generation in protocol-B and at 20th generation in both protocols, showed stability of ploidy level. SSR assessment of TC-regenerates at 20th generation in both protocols confirmed genetic homogeneity. The results confirmed the genetic stability of the TC-regenerates and demonstrated the reliability of the regeneration systems developed so far using explants of two different origins, for large-scale multiplication of elite genotypes of Jatropha.
    Applied biochemistry and biotechnology 09/2013; 172(1). · 1.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Soil salinity adversely affects plant growth and development and disturbs intracellular ion homeostasis resulting cellular toxicity. The Salt Overly Sensitive 1 (SOS1) gene encodes a plasma membrane Na+/H+ antiporter that plays an important role in imparting salt stress tolerance to plants. Here, we report the cloning and characterisation of the SbSOS1 gene from Salicornia brachiata, an extreme halophyte. RESULTS: The SbSOS1 gene is 3774 bp long and encodes a protein of 1159 amino acids. SbSOS1 exhibited a greater level of constitutive expression in roots than in shoots and was further increased by salt stress. Overexpressing the S. brachiata SbSOS1 gene in tobacco conferred high salt tolerance, promoted seed germination and increased root length, shoot length, leaf area, fresh weight, dry weight, relative water content (RWC), chlorophyll, K+/Na+ ratio, membrane stability index, soluble sugar, proline and amino acid content relative to wild type (WT) plants. Transgenic plants exhibited reductions in electrolyte leakage, reactive oxygen species (ROS) and MDA content in response to salt stress, which probably occurred because of reduced cytosolic Na+ content and oxidative damage. At higher salt stress, transgenic tobacco plants exhibited reduced Na+ content in root and leaf and higher concentrations in stem and xylem sap relative to WT, which suggests a role of SbSOS1 in Na+ loading to xylem from root and leaf tissues. Transgenic lines also showed increased K+ and Ca2+ content in root tissue compared to WT, which reflect that SbSOS1 indirectly affects the other transporters activity. CONCLUSIONS: Overexpression of SbSOS1 in tobacco conferred a high degree of salt tolerance, enhanced plant growth and altered physiological and biochemical parameters in response to salt stress. In addition to Na+ efflux outside the plasma membrane, SbSOS1 also helps to maintain variable Na+ content in different organs and also affect the other transporters activity indirectly. These results broaden the role of SbSOS1 in planta and suggest that this gene could be used to develop salt-tolerant transgenic crops.
    BMC Plant Biology 10/2012; 12(1):188. · 3.94 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Salinity severely affects plant growth and development. Plants evolved various mechanisms to cope up stress both at molecular and cellular levels. Halophytes have developed better mechanism to alleviate the salt stress than glycophytes, and therefore, it is advantageous to study the role of different genes from halophytes. Salicornia brachiata is an extreme halophyte, which grows luxuriantly in the salty marshes in the coastal areas. Earlier, we have isolated SbASR-1 (abscisic acid stress ripening-1) gene from S. brachiata using cDNA subtractive hybridisation library. ASR-1 genes are abscisic acid (ABA) responsive, whose expression level increases under abiotic stresses, injury, during fruit ripening and in pollen grains. The SbASR-1 transcript showed up-regulation under salt stress conditions. The SbASR-1 protein contains 202 amino acids of 21.01-kDa molecular mass and has 79 amino acid long signatures of ABA/WDS gene family. It has a maximum identity (73 %) with Solanum chilense ASR-1 protein. The SbASR-1 has a large number of disorder-promoting amino acids, which make it an intrinsically disordered protein. The SbASR-1 gene was over-expressed under CaMV 35S promoter in tobacco plant to study its physiological functions under salt stress. T(0) transgenic tobacco seeds showed better germination and seedling growth as compared to wild type (Wt) in a salt stress condition. In the leaf tissues of transgenic lines, Na(+) and proline contents were significantly lower, as compared to Wt plant, under salt treatment, suggesting that transgenic plants are better adapted to salt stress.
    Marine Biotechnology 05/2012; 14(6). · 3.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Genetic engineering of plants for abiotic stress tolerance is a challenging task because of its multifarious nature. Comprehensive studies for developing abiotic stress tolerance are in progress, involving genes from different pathways including osmolyte synthesis, ion homeostasis, antioxidative pathways, and regulatory genes. In the last decade, several attempts have been made to substantiate the role of “single-function” gene(s) as well as transcription factor(s) for abiotic stress tolerance. Since, the abiotic stress tolerance is multigenic in nature, therefore, the recent trend is shifting towards genetic transformation of multiple genes or transcription factors. A large number of crop plants are being engineered by abiotic stress tolerant genes and have shown the stress tolerance mostly at laboratory level. This review presents a mechanistic view of different pathways and emphasizes the function of different genes in conferring salt tolerance by genetic engineering approach. It also highlights the details of successes achieved in developing salt tolerance in plants thus far.
    Molecular Biotechnology 05/2012; 54(1). · 2.28 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Salicornia brachiata is one of the extreme salt tolerant plants and grows luxuriantly in coastal areas. Previously we have reported isolation and characterization of ESTs from S. brachiata with large number of unknown gene sequences. Reverse Northern analysis showed upregulation and downregulation of few unknown genes in response to salinity. Some of these unknown genes were made full length and their functional analysis is being tested. In this study, we have selected a novel unknown salt inducible gene SbSI-1 (Salicornia brachiata salt inducible-1) for the functional validation. The SbSI-1 (Gen-Bank accession number JF 965339) was made full length and characterized in detail for its functional validation under desiccation and salinity. The SbSI-1 gene is 917 bp long, and contained 437 bp 3' UTR, and 480 bp ORF region encoding 159 amino acids protein with estimated molecular mass of 18.39 kDa and pI 8.58. The real time PCR analysis revealed high transcript expression in salt, desiccation, cold and heat stresses. However, the maximum expression was obtained by desiccation. The ORF region of SbSI-1 was cloned in pET28a vector and transformed in BL21 (DE3) E. coli cells. The SbSI-1 recombinant E. coli cells showed tolerance to desiccation and salinity stress compared to only vector in the presence of stress.
    Molecular Biology Reports 06/2011; 39(2):1943-8. · 1.96 Impact Factor
  • Pushp Sheel Shukla, Pradeep K. Agarwal, Bhavanath Jha
    [Show abstract] [Hide abstract]
    ABSTRACT: Salinity adversely affects plant growth and development. Halotolerant plant-growth-promoting rhizobacteria (PGPR) alleviate salt stress and help plants to maintain better growth. In the present study, six PGPR strains were analyzed for their involvement in salt-stress tolerance in Arachis hypogaea. Different growth parameters, electrolyte leakage, water content, biochemical properties, and ion content were analyzed in the PGPR-inoculated plants under 100 mM NaCl. Three bacterial strains, namely, Brachybacterium saurashtrense (JG-06), Brevibacterium casei (JG-08), and Haererohalobacter (JG-11), showed the best growth of A. hypogaea seedlings under salt stress. Plant length, shoot length, root length, shoot dry weight, root dry weight, and total biomass were significantly higher in inoculated plants compared to uninoculated plants. The PGPR-inoculated plants were quite healthy and hydrated, whereas the uninoculated plant leaves were desiccated in the presence of 100 mM NaCl. The percentage water content (PWC) in the shoots and roots was also significantly higher in inoculated plants compared to uninoculated plants. Proline content and soluble sugars were significantly low, whereas amino acids were higher than in uninoculated plants. The MDA content was higher in uninoculated plants than in inoculated plants at 100 mM NaCl. The inoculated plants also had a higher K+/Na+ ratio and higher Ca2+, phosphorus, and nitrogen content. The auxin concentration was higher in both shoot and root explants in the inoculated plants. Therefore, it could be predicted that all these parameters cumulatively improve plant growth under saline conditions in the presence of PGPR. This study shows that PGPR play an important role in inducing salinity tolerance in plants and can be used to grow salt-sensitive crops in saline areas.
    Journal of Plant Growth Regulation 06/2011; 31(2). · 2.06 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Salinity causes multifarious adverse effects to plants. Plants response to salt stress involves numerous processes that function in coordination to alleviate both cellular hyperosmolarity and ion disequilibrium. A Na+/H+ antiporter NHX1 gene has been isolated from a halophytic plant Salicornia brachiata in this study. Predicted amino acid sequence similarity, protein topology and the presence of functional domains conserved in SbNHX1 classify it as a plant vacuolar NHX gene. The SbNHX1 cDNA has an open reading frame of 1,683bp, encoding a polypeptide of 560 amino acid residues with an estimated molecular mass 62.44kDa. The SbNHX1 shows high amino acid similarity with other halophytic NHX gene and belongs to Class-I type NHXs. TMpred suggests that SbNHX1 contains 11 strong transmembrane (TM). Real time PCR analysis revealed that SbNHX1 transcript expresses maximum at 0.5M. Transcript increases gradually by increasing the treatment duration at 0.5M NaCl, however, maximum expression was observed at 48h. The overexpression of SbNHX1 gene in tobacco plant showed NaCl tolerance. This study shows that SbNHX1 is a potential gene for salt tolerance, and can be used in future for developing salt tolerant crops. KeywordsAntiporter–Halophyte–Ion homeostasis– Salicornia brachiata –Vacuolar NHX
    Molecular Biology Reports 01/2011; 38(3):1965-1973. · 1.96 Impact Factor
  • Source
    Kapil Gupta, Pradeep K Agarwal, M K Reddy, Bhavanath Jha
    [Show abstract] [Hide abstract]
    ABSTRACT: Dehydration-responsive element binding (DREB) transcription factor plays a key role in plant stress signal transduction pathway. In this study, SbDREB2A has been isolated from the halophyte Salicornia brachiata. SbDREB2A cDNA is 1,062 bp long, encoding protein of 353 amino acids with an estimated molecular mass of 39.37 kDa and a pI of 4.98. On the basis of multiple sequence alignment and phylogenetic analysis, SbDREB2A is classified in A-2 group of the DREB family. The genomic organization confirms that SbDREB2A is an intronless gene. Purified recombinant SbDREB2A protein showed similar binding to both DREs (dehydration-responsive element), ACCGAC and GCCGAC. The transcript expression of SbDREB2A was induced by NaCl, drought and heat stress. The role of SbDREB2A in abiotic stress was studied in E. coli BL21 (DE3). The recombinant E. coli cells exhibited better growth in basal LB medium as well as in supplemented with NaCl, PEG and mannitol. The enhanced growth in recombinant E. coli could be due to the regulation of stress regulated functional genes by this transcription factor. This system can be applied in biotechnological applications, where growth of E. coli can be enhanced under salt stress for efficient recombinant protein production in a short span of time.
    Plant Cell Reports 10/2010; 29(10):1131-7. · 2.94 Impact Factor
  • P. K. Agarwal, B. Jha
    [Show abstract] [Hide abstract]
    ABSTRACT: Plants face variable environmental stresses that negatively affect plant growth and productivity. The multiplicity of responses is an important aspect of the complexity of stress signalling. Abscisic acid (ABA) is a broad-spectrum phytohormone involved not only in regulating stomatal opening, growth and development but also in coordinating various stress signal transduction pathways in plants during abiotic stresses. The both ABA-dependent and ABA-independent signal transduction pathways from stress signal perception to gene expression involve different transcription factors such as DREB, MYC/MYB, AREB/ABF, NAM, ATAF1,2, CUC and their corresponding cis-acting elements DRE, MYCRS/MYBRS, ABRE, NACRS. Genetic analysis of ABA mutants has given insight that ABA-dependent and ABA-independent pathways for osmotic stress and cold stress interact and converge. This review focuses on ABA-dependent and ABA-independent transcriptional components and cascades, their specificity and crosstalk in stress gene regulation. Additional key words cis-element-cross talk-downstream genes-gene regulation-overexpression
    Biologia Plantarum 06/2010; 54(2):201-212. · 1.74 Impact Factor
  • Parinita Agarwal, M. K. Reddy, S. K. Sopory, Pradeep K. Agarwal
    [Show abstract] [Hide abstract]
    ABSTRACT: Rab proteins form the largest family of small guanosine triphosphate (GTP)-binding proteins. The Rab family in plants is divided into eight subfamilies, Rab1, Rab2, Rab5, Rab6, Rab7, Rab8, Rab11, and Rab18. Phylogenetic analyses of amino acid sequence of Rab GTPases suggest their segregation into subfamilies on the basis of their localization and/or function in membrane trafficking. The Rab GTPases are localized to the cytosolic face of specific intracellular membranes, where they function as regulators of distinct steps in membrane-trafficking pathways. The Rab proteins show highly conserved structural features with a great functional versatility. They play an important role in regulating hormone signaling during fruit ripening and apical dominance, brassinosteroid biosynthesis, pollen and nodule development, and in response to both abiotic and biotic stresses.
    Plant Molecular Biology Reporter 12/2009; 27(4):417-430. · 2.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The DREB transcription factors comprise conserved ERF/AP2 DNA-binding domain, bind specifically to DRE/CRT motif and regulate abiotic stress mediated gene expression. In this study we show that PgDREB2A from Pennisetum glaucum is a powerful transcription factor to engineer multiple stress tolerance in tobacco plants. The PgDREB2A protein lacks any potential PEST sequence, which is known to act as a signal peptide for protein degradation. Therefore, the transgenic tobacco plants were raised using full-length cDNA without modification. The transgenics exhibited enhanced tolerance to both hyperionic and hyperosmotic stresses. At lower concentration of NaCl and mannitol, seed germination and seedling growth was similar in WT and transgenic, however at higher concentration germination in WT decreased significantly. D15 and D46 lines showed 4-fold higher germination percent at 200 mM NaCl. At 400 mM mannitol seed germination in WT was completely arrested, whereas in transgenic line it was more than 50%. Seedlings of D15 and D46 lines showed better growth like leaf area, root number, root length and fresh weight compared to wild type for both the stresses. The quantitative Real time PCR of transgenic showed higher expression of downstream genes NtERD10B, HSP70-3, Hsp18p, PLC3, AP2 domain TF, THT1, LTP1 and heat shock (NtHSF2) and pathogen-regulated (NtERF5) factors with different stress treatments.
    Molecular Biology Reports 10/2009; 37(2):1125-35. · 1.96 Impact Factor

Publication Stats

653 Citations
64.13 Total Impact Points

Institutions

  • 2010–2014
    • Central Salt and Marine Chemicals Research Institute
      Baunagar, Gujarāt, India
  • 2004–2009
    • International Centre for Genetic Engineering and Biotechnology
      • Plant Biology: Plant Molecular Biology Research Group
      Trst, Friuli Venezia Giulia, Italy
  • 1992–2006
    • University of Delhi
      Old Delhi, NCT, India