Genetically modified cyanobacterium Nostoc muscorum overproducing proline in response to salinity and osmotic stresses.
In the parent Nostoc 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 O 2 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.
Bhargava
Santosh
S
Department of Botany, Swami Vivekanand Government College, Raisen 464 551, India. santoshbhargava@hotmail.com
D001383:Azetidinecarboxylic Acid / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D009154:Mutation; D050502:Nostoc muscorum / Q000235:genetics / Q000378:metabolism; D030781:Organisms, Genetically Modified; D009997:Osmotic Pressure; D011188:Potassium / Q000378:metabolism; D011392:Proline / Q000378:metabolism*; D011394:Proline Oxidase / Q000378:metabolism; D012492:Salts / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism
D001426:Bacterial Proteins; D012492:Salts; D013395:Sucrose; D001383:Azetidinecarboxylic Acid; D011392:Proline; D011394:Proline Oxidase; D011188:Potassium