Role of Iron Uptake Systems in Coordinating Iron Homeostasis in NaCl-resistant Mutant of the Cyanobacterium Nostoc muscorum

Aims: To investigate the effect of NaCl stress on parent Nostoc muscorum and its spontaneously occurring mutant clone showing resistance to growth inhibitory action of NaCl in terms of various physiological parameters. We have further analyzed the role of iron uptake systems in providing a resistant phenotype.

Place and Duration of Study: Division of Microbiology, Department of Botany, Government Motilal Science College, Bhopal 462008 (M.P.) India. This work was carried out between August 2021 to May 2022.

Methodology: We have examined the various physiological parameters viz. growth, specific growth rate, photosynthetic O2 evolution, and nitrogenase activity as per the prescribed protocol. Further, DNA microarray analysis was carried out using the Agilent platform.

Results: NaCl stress adversely affected growth, photosynthetic O2 evolution, and nitrogenase activity of the wild-type Nostoc muscorum, while NaCl-resistant mutant remains unaffected under a given stress. Microarray data analysis identified 24 ORF related to the uptake of iron with fold regulation ≥2 in the mutant strain. These ORFs belonging to the ABC-type ferric iron transporter that plays a significant role in the iron acquisition were identified in the mutant strain.

Conclusion: The mechanism of iron homeostasis in the NaCl-resistant mutant has been explained. The results presented are essential to explain the regulatory role of the iron uptake system in stressed conditions.