Comparative analysis was performed with a CFo ATP synthase subunit If homologue (CFo-II) derived from marine or fresh-water algae. The marine algae-derived CFo-II-transformed Escherichia coli grew and accumulated ATP more vigorously in NaCl or Cadmium containing medium, suggesting that this gene was useful for the development of stress-tolerant plant. (C) 2009, The Society for Biotechnology, Japan. All rights reserved.