Genetically modified cyanobacteriumNostoc muscorum overproducing proline in response to salinity and osmotic stresses |
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Authors: | Santosh Bhargava |
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Affiliation: | (1) Department of Botany, Swami Vivekanand Government College, 464 551 Raisen, India |
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Abstract: | In the parentNostoc muscorum an active proline oxidase enzyme is required to assimilate exogenous proline as a fixed nitrogen source. Cyanobacterial mutants, resistant to growth inhibitory action of proline analogue L-azetidine-2-carboxylate (Ac-R), were deficient in proline oxidase activity, and were over-accumulators of proline. Proline over-accumulation, resulting either from mutational acquisition of the Ac-R phenotype, or from salinity-induced uptake of exogenous proline, confirmed enhanced salinity/osmotic tolerance in the mutant strain. The nitrogenase activity and photosynthetic O2 evolution of the parent were sensitive to both salinity as well as osmotic stresses than of Ac-R mutant strain. In addition, the mutation to Ac-resistant phenotype showed no alteration in salinity inducible potassium transport system in the cyanobacterium. |
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Keywords: | Diazotrophy L-azetidine-2-carboxylate mutation proline accumulation proline oxidase salinity/osmotic stress |
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