title: Overexpression of Ran gene from Lepidium latifolium L. (LlaRan) renders transgenic tobacco plants hypersensitive to cold stress.
abstract: Ran is a multifunctional small GTPase involved in important cellular activities like nucleocytoplasmic transport, mitotic spindle assembly, nuclear envelope formation, etc., but is also known to be differentially expressed in response to abiotic stress, particularly low temperature. We have over-expressed Lepidium latifolium (Fam. Brassicaceae) Ran gene in tobacco to study the response of the plants to cold stress (24 h; 4 °C). Transformation of the tobacco plants was verified using PCR targeting Ran gene and co-transformed selectable marker gene nptII. Segregation in Mendelian ratios was validated in five transgenic lines by germination of T1 and T2 seeds on moist filter papers containing 150 mg/l kanamycin. Higher levels of electrolyte leakage and lipid peroxidation pointed towards hypersensitivity of plants. Similarly, lesser proline accumulation compared to wild types also indicated susceptibility of plants to death under chilling conditions. Specific activity of antioxidant enzymes superoxide dismutase and glutathione reductase was also measured under stressed and control conditions. A variation was observed across the different lines, and four out of five lines showed lesser specific activity compared to wild type plants, thus indicating reduced capability of scavenging free radicals. In totality, a strong evidence on induced hypersensitivity to cold stress has been collected which may further be helpful in designing appropriate strategies for engineering crop plants for survival under cold stress conditions.
authors: Defence Institute of Bio-Energy Research, Goraparao, P.O. Arjunpur, Haldwani, 263139, India, vimlendusinha@gmail.com.
authors: Vimlendu Bhushan
authors: VB
authors: Sinha
authors: Atul
authors: A
authors: Grover
authors: Sadhana
authors: S
authors: Singh
authors: Veena
authors: V
authors: Pande
authors: Zakwan
authors: Z
authors: Ahmed
mesh_terms: D058639:Cold-Shock Response / Q000235:genetics*; D017343:Genes, Plant; D005980:Glutathione Reductase / Q000378:metabolism; D029686:Lepidium / Q000235:genetics*; D015227:Lipid Peroxidation / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014026:Nicotiana / Q000235:genetics*; D019076:Transgenes; D015854:Up-Regulation; D020931:ran GTP-Binding Protein / Q000235:genetics*
chemical_list: D010940:Plant Proteins; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D020931:ran GTP-Binding Protein