Salt and osmotic stress response of tobacco plants overexpressing Lepidium latifolium L. Ran GTPase gene

Abstract

Our earlier study has identified Lepidium latifolium Ran (LlaRan) as a cold stress downregulated gene from L. latifolium, a cold desert plant. Further, independent transgenic tobacco (Nicotiana tabacum L. var Xanthi) lines overexpressing LlaRan were developed for functional characterization of the gene. We analysed the tolerance of tobacco plants over expressing LlaRan gene to salt and PEG stresses at germination which represents a critical stage in life cycle of the plants. Germination performance of the four independent transgenic lines (T1 generation) were assessed for germination under distilled water, NaCl (150 mM) and osmotic (15% PEG 4000) stresses. The emergence of radical, plumule and cotyledonary leaf were recorded for 10 days on daily basis and its rate assessed in terms of Timson’s index. It was observed that the germination of wild type tobacco seeds was better than the assessed transgenic lines. It may be inferred that the transgenic lines seeds under study were more sensitive to salt and drought stress elucidating their hypersensitivity at germination level.