Azorhizobium caulinodans Th 4A genome sequencing project

Azorhizobium caulinodans Th 4A (MAFF 210287) is a strain of rhizobia originally isolated from Sesbania rostrata in Thailand. Two features distinguish A. caulinodans from other rhizobia: stem nodule formation and its dual capacity for free-living and symbiotic nitrogen fixation. Although many rhizobia induce the formation of new organs of nodules that typically occur on roots, this species forms stem-located aerial nodules to host plants. It is known that the species of rhizobia that can fix nitrogen under aerobic free-living conditions are rare. The genome sequence of A. caulinodans Th 4A could contribute to understanding the evolution of rhizobia and the molecular basis underlying stem nodulation and nitrogen fixation of rhizobia under free-living conditions.