Pervasive RNA Regulation of Metabolism Enhances the Root Colonization Ability of Nitrogen-Fixing Symbiotic α-Rhizobia
Natalia I. García‐Tomsig, Marta Robledo, George C. diCenzo, Alessio Mengoni, Vicenta Millán, Alexandra Peregrina, Alejandro Uceta, José I. Jiménez‐Zurdo
Abstract
Nitrogen-fixing root nodule symbioses between rhizobia and legume plants provide more than half of the combined nitrogen incorporated annually into terrestrial ecosystems, rendering plant growth independent of environmentally unfriendly chemical fertilizers. The success of symbiosis depends primarily on the capacity of rhizobia to establish competitive populations in soil and rhizosphere environments. Here, we provide insights into the regulation and architecture of an extensive RNA posttranscriptional network that fine-tunes the metabolism of the alfalfa symbiont S. meliloti, thereby enhancing the ability of this beneficial bacterium to colonize nutrient-rich but extremely selective niches, such as the rhizosphere of its host plant. This pervasive RNA regulation of metabolism is a major adaptive mechanism, predicted to operate in diverse rhizobial species. Because RNA regulation relies on modifiable base-pairing interactions, our findings open unexplored avenues for engineering the legumes rhizobiome within sustainable agricultural practices.