The role of potassium as an ionic signal in the regulation of cyanobacterium Nostoc muscorum response to salinity and osmotic stress.
Spontaneously occurring thallium-resistant (Tl+ -R) mutant of diazotrophic, heterocystous cyanobacterium Nostoc muscorum is described in which Tl+ -R phenotype is the cause of defective salinity-inducible K+ uptake activity and proline uptake activity. The results indicate that mutant strain is more sensitive to salinity and osmotic stresses than its parent. The mutational inactivation of salinity-inducible proline uptake was found associated with increased sensitivity of the cyanobacterial photosynthetic O2 evolution and nitrogenase activity under salinity and osmotic stresses. It is suggested that in the cyanobacterium Nostoc muscorum K+ functions as a primary osmolyte which is associated with salinity-inducible proline uptake leading to the acquisition of salt tolerance in the cyanobacterium.
Bhargava
Santosh
S
Department of Botany, Swami Vivekanand Government College, Raisen 464551 (M.P.), India. santoshbhargava@hotmail.com
D000222:Adaptation, Physiological; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001692:Biological Transport; D015169:Colony Count, Microbial; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial; D009591:Nitrogenase / Q000378:metabolism; D046937:Nostoc / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D009997:Osmotic Pressure; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D011188:Potassium / Q000378:metabolism*; D011392:Proline / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D013793:Thallium / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D011392:Proline; D012964:Sodium; D013793:Thallium; D009591:Nitrogenase; D011188:Potassium; D010100:Oxygen