Genome characteristics of facultatively symbiotic Frankia sp. strains reflect host range and host plant biogeography

Various researches are conducted to study the genome characteristics of three closely related clades of Frankia sp. strains, which are commonly recognized as the facultative symbionts forming nitrogen-fixing root nodules in several plants. The results demonstrate that such soil bacteria can undergo major genome expansions, as well as reductions, as they respond to new environments in the context of their symbioses and hence reflect host range and host plant biogeography.