Digital Commons Network^™

Nitrogen Fixation Mutants Of The Actinobacterium Frankia Casuarinae Cci3, Ken-Ichi Kucho, Daiki Tamari, Shintaro Matsuyama, Takeshi Nabekura, Louis S. Tisa

Molecular, Cellular & Biomedical Sciences

Frankia is a representative genus of nitrogen-fixing (N2-fixing) actinobacteria; however, the molecular mechanisms underlying various phenomena such as the differentiation of a N2 fixation-specific structure (vesicle) and the regulation of N2 fixation (nif) genes, have yet to be elucidated in detail. In the present study, we screened hyphal fragments of Frankia casuarinae that were mutagenized by 1-methyl-3-nitro-1-nitrosoguanidine or gamma rays, and isolated 49 candidate N2 fixation mutants. Twelve of these mutants were selected for further study, and their abilities to grow in NH3-deficient (N-) liquid media and their rates of acetylene reduction activities were evaluated. Eleven mutant strains were confirmed …