A reconsideration of terminology in Frankia research: A need for congruence

Progress in understanding the Frankia -actinorhizal symbiosis has paralleled that of the Rhizobium -legume symbiosis. Previously, these two nitrogen-fixing symbioses have been considered as distinct and unrelated entities. However, it seems likely that many of the developmental stages, and perhaps even the molecular signals, are shared between these two apparently independent associations. For this reason, we propose to emphasize the similarities between the two symbioses by calling for a uniformity of terminology to describe nodule development.