The Response of Rhizobacteria Pseudomonas Fluorescens to Applied Electrical Fields

Summary: Rhizobacteria show electrotactic swimming in the rhizosphere as stimulated by plant roots. The electrotactic response of four strains of rhizobacteria ,Pseudomonas fluorescens (P.fluorescens)-P.fluorescens290E,P.fluorescens-M,P.fluorescens- 292 and P.fluorescens-WCS 374 was observed in vitro conditions to different electrical fields in Phosphate Buffer Solution (PBS),root Exudate (RE) and Water (W).Electrical fields occurs in vitro condition is comparable in magnitude to those generated by plant root in the rhizosphere. The electrotactic response was greatest in phosphate buffer solution followed by root exudate and water. In the electrical fields tactic response of P.fluroscens-290E and P.fluroscens-WCS-374 was towards anode. However P.fluroscens-292 and P.fluroscens-M was towards cathode .Electrical field of physiological magnitude had little effect on the velocity of swimming but increased the turning frequency of P. fluroscens over two fold. The swimming behaviour of these rhizobacteria was greater at low electrical field strength as compared to high electrical field and control conditions. The results suggest that swimming behaviour of these rhizobacteria is related to endogenous electrical gradients generated by growing roots or other plant tissues .