Publications of NIPGR Scientists

Permanent URI for this communityhttps://ndkr-library.nipgr.ac.in/handle/123456789/1

Browse

End date: 2009Subject: search.filters.subject.Stress

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    CIPK6, a CBL-interacting protein kinase is required for development and salt tolerance in plant
    (Wiley-Blackwell, 2009) Tripathi, Vineeta; Parasuraman, Boominathan; Laxmi, Ashverya; Chattopadhyay, Debasis
    Calcineurin B-like proteins (CBL) and CBL-interacting protein kinases (CIPK) mediate plant responses to a variety of external stresses. Here we report that Arabidopsis CIPK6 is also required for the growth and development of plants. Phenotype of tobacco plants ectopically expressing a homologous gene (CaCIPK6) from the leguminous plant chickpea (Cicer arietinum) indicated its functional conservation. A lesion in AtCIPK6 significantly reduced shoot-to-root and root basipetal auxin transport, and the plants exhibited developmental defects such as fused cotyledons, swollen hypocotyls and compromised lateral root formation, in conjunction with reduced expression of a number of genes involved in auxin transport and abiotic stress response. The Arabidopsis mutant was more sensitive to salt stress compared to wild-type, while overexpression of a constitutively active mutant of CaCIPK6 promoted salt tolerance in transgenic tobacco. Furthermore, tobacco seedlings expressing the constitutively active mutant of CaCIPK6 showed a developed root system, increased basipetal auxin transport and hypersensitivity to auxin. Our results provide evidence for involvement of a CIPK in auxin transport and consequently in root development, as well as in the salt-stress response, by regulating the expression of genes.
  • Thumbnail Image
    Item
    Characterization and phylogenetic analysis of environmental stress responsive SAP gene family encoding A20/AN1 zinc-finger proteins in tomato
    (Springer, 2009) Solanke, Amolkumar U.; Sharma, Manoj K.; Tyagi, Akhilesh K.; Sharma, Arun Kumar
    Characterization of genes responsive to stress is important for eVorts on improving stress tolerance of plants. To address components involved in stress tolerance of tomato (Solanum lycopersicum), a stress-responsive gene family encoding A20/AN1 zinc Wnger proteins was characterized. In the present study, 13 members of this gene family were cloned from tomato cultivar Pusa Ruby and named as Stress Associated Protein (SAP) genes. Out of 13 genes, 12 have been mapped on their respective chromo- somes. Expression of these genes in response to cold, heat, salt, desiccation, wounding, abscisic acid, oxidative and submergence stresses was analysed. All tomato SAP genes were found to be responsive to one or other type of environ- mental stress. The phylogenetic analysis of these genes, along with their orthologs from Solanaceae species sug- gests the presence of a common set of SAP genes in the studied Solanaceae species. The present study characterizes a SAP gene family, which encodes A20/AN1 zinc Wnger containing proteins from tomato for the Wrst time. Genes showing high expression in response to a particular stress can be exploited for improving stress tolerance of tomato and other Solanaceae members.
  • Thumbnail Image
    Item
    Differential responses of arsenic stress in two varieties of Brassica juncea
    (Elsevier B.V., 2009) Gupta, Meetu; Sharma, Pallavi; Sarin, Neera Bhalla; Sinha, Alok Krishna
    Present study showed the toxicity caused by Arsenite (As(III)) and its detoxification responses in two varieties (Varuna and Pusa Bold) of Brassica juncea. Comparisons were made in leaves and roots of both the varieties, which showed that the accumulation pattern in both the varieties were dose and duration dependent, being more in roots for two days and in leaves for four days. Increase/decrease of antioxidant enzymes activities (SOD, CAT, GPX) showed not much changes at the given concentrations except that the enzyme activities showed significant increase at the lower concentrations. Semi quantitative RT-PCR analysis of PCS showed more expression of its transcript in P. Bold as compared to Varuna variety due to As(III) stress. The analysis of isoenzyme pattern in leaves of P. Bold showed five and two major bands of SOD and GPX, respectively. As(III) treatment leads to the activation of MAPK activity indicating role of this important cascade in transducing As(III) mediated signals. The data presented indicates the differential responses in both the varieties and also that the increased tolerance in P. Bold may be due to the defensive role of antioxidant enzymes, induction of MAPK and up regulation of PCS transcript which is responsible for the production of metal binding peptides.
  • Thumbnail Image
    Item
    Cloning and characterization of a novel LpWRKY1 transcription factor in tomato
    (Elsevier B.V., 2008) Hofmann, Markus Georg; Sinha, Alok Krishna; Proels, Reinhard Korbinian; Roitsch, Thomas
    The initiation of defence responses in plants is accompanied by fundamental changes in gene expression: the expression of pathogenesis- related genes is co-ordinately regulated with metabolic changes such as down regulation of photosynthesis and induction of sink metabolism. To identify candidate regulators of this co-ordinated regulatory mechanism, the role of WRKY transcription factors in the initiation of defence response was analysed in tomato. A WRKY-type transcription factor (LpWRKY1) from tomato was cloned by a reverse Northern approach. The corresponding mRNA is rapidly and transiently induced after challenging the cells with an elicitor-preparation derived from the wilt inducing fungus Fusarium oxysporum lycopersici (E-FOL) and the fungal elicitor chitosan, whereas the endogenous signals systemin and salicylic acid are inactive. Inhibition of protein biosynthesis by cycloheximide results in sustained induction of mRNA for LpWRKY1. In contrast, the transient induction of the gene encoding LpWRKY1 in response to elicitation by E-FOL is inhibited by the protein-kinase inhibitor staurosporine and may be mimicked by the phosphatase inhibitors endothall and cantharidine indicating the involvement of protein phosphorylation in the regulation of WRKY-type transcription factors. Direct proof of this postranslational modification of LpWRKY1 was obtained by demonstrating in-gel kinase assays using recombinant LpWRKY1 as substrate. A 44 kDa and a 67 kDa protein kinase were shown to be transiently activated to phosphorylate LpWRKY1 protein in response to elicitation with E-FOL.
  • Thumbnail Image
    Item
    Regulation of TOP2 by various abiotic stresses including cold and salinity in pea and transgenic tobacco plants
    (Oxford University Press, 2005) Hettiarachchi, Gardhi H. C. M.; Reddy, Malireddy K.; Sopory, Sudhir K.; Chattopadhyay, Sudip
    Although abiotic stress affects plant growth and development, demonstration of its direct effect on regulation of the components of the DNA replication machinery is largely unknown. In this work, we demonstrate that the expression of TOP2 (encoding topoisomerase II) is up-regulated by various abiotic stresses including salinity and low temperature, and phytohormones such as ABA (abscisic acid) and SA (salicylic acid). Transgenic studies with different deletion versions of the TOP2 promoter in tobacco define several promoter determinants responsible for specific abiotic stress responsiveness. Taken together, these results demonstrate a direct involvement of stress in the transcriptional regulation of TOP2.