Extended hopanoid lipids promote bacterial motility, surface attachment, and root nodule development in the Bradyrhizobium diazoefficiens-Aeschynomene afraspera symbiosis

摘要: Hopanoids are steroid-like bacterial lipids that enhance membrane rigidity and promote growth under diverse stresses. Roughly 10% of bacteria contain genes involved in hopanoid biosynthesis, these particularly conserved plant-associated organisms. We previously found the extended class hopanoids (C35) nitrogen-fixing soil bacterium Bradyrhizobium diazoefficiens promotes its root nodule symbiosis with tropical legume Aeschynomene afraspera. By quantitatively modeling development, we identify independent roles for initiation formation determining rate maturation. In vitro studies demonstrate support B. motility surface attachment, which may correlate stable colonization planta. Confocal microscopy maturing nodules reveals infected hopanoid-deficient unusually low densities symbionts, indicating necessary persistent, high levels host infection. This work identifies as regulators efficiency Bradyrhizobia symbioses, agriculturally economically significant associations growing importance a changing climate.