Swimming performance of Bradyrhizobium diazoefficiens is an emergent property of its two flagellar systems

J.I. QUELAS; M.J. ALTHABEGOITI; C. JIMENEZ SANCHEZ; A.A. MELGAREJO; VERONICA I. MARCONI; E. J. MOGIARDINI; S. TREJO; FLORENCIA MENGUCCI; J.J. ORTEGA CALVO; A.R. LODEIRO

Scientific Reports

Nature Publishing Group

Lugar: United Kingdom; Año: 2016 vol. 6 p. 23841 - 2384114

Many bacterial species use flagella for self-propulsion in aqueous media. In the soil, which is a complexand structured environment, water is found in microscopic channels where viscosity and water potentialdepend on the composition of the soil solution and the degree of soil water saturation. Therefore,the motility of soil bacteria might have special requirements. An important soil bacterial genus isBradyrhizobium, with species that possess one flagellar system and others with two different flagellarsystems. Among the latter is B. diazoefficiens, which may express its subpolar and lateral flagellasimultaneously in liquid medium, although its swimming behaviour was not described yet. Thesetwo flagellar systems were observed here as functionally integrated in a swimming performance thatemerged as an epistatic interaction between those appendages. In addition, each flagellum seemedengaged in a particular task that might be required for swimming oriented toward chemoattractantsnear the soil inner surfaces at viscosities that may occur after the loss of soil gravitational water.Because the possession of two flagellar systems is not general in Bradyrhizobium or in related generathat coexist in the same environment, there may be an adaptive tradeoff between energetic costs andecological benefits among these different species.