Interpopulation signaling via N-acyl-homoserine lactones among bacteria in the wheat rhizosphere

• Published in: Molecular plant-microbe interactions Vol. 11; no. 11; pp. 1078 - 1084
• Main Authors: Pierson, E.A. (University of Arizona, Tucson, AZ.), Wood, D.W, Cannon, J.A, Blachere, F.M, Pierson, L.S. III
• Format: Journal Article
• Language: English
• Published: St Paul, MN APS Press 01.11.1998; The American Phytopathological Society
• Subjects: AZINAS; AZINE; AZINES; BACTERIA; BIOASSAYS; BIOCHEMICAL PATHWAYS; Biological and medical sciences; Biological control; COMPLEMENTATION; Control; ENSAYO BIOLOGICO; ESPECE; ESPECIES; EXPRESION GENICA; EXPRESSION DES GENES; FLORA DEL SUELO; FLORE DU SOL; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; GENE; GENE EXPRESSION; GENES; GENETICA; GENETICS; GENETIQUE; GEOGRAPHICAL VARIATION; LACTONAS; LACTONE; LACTONES; phenazine antibiotics; PHENAZINES; Phytopathology. Animal pests. Plant and forest protection; Pseudomonas aureofaciens; quorum sensing; RACINE; RAICES; RECEPTORS; REPORTER GENES; RHIZOSPHERE; RIZOSFERA; ROOTS; SOIL FLORA; SPECIES; SYMPATRIC SPECIES; TEST BIOLOGIQUE; TRITICUM AESTIVUM; VIA BIOQUIMICA DEL METABOLISMO; VOIE BIOCHIMIQUE DU METABOLISME; Pseudomonadales; Monocotyledones; Microorganism interrelationships; Plant pathogen; Mycosis; Biological control; Lactone; Biosynthesis; Cereal crop; Infection; α-Aminoacid; Phenazine derivatives; Pseudomonas aureofaciens; Rhizosphere; Antifungal agent; Regulation(control); Rhizobacteria; Gramineae; Angiospermae; Bacteria; Pseudomonadaceae; Spermatophyta; Triticum aestivum
• ISSN: 0894-0282; 1943-7706
• DOI: 10.1094/mpmi.1998.11.11.1078

The biological control bacterium Pseudomonas aureofaciens 30-84 utilizes an N-acyl-homoserine lactone (AHL) signal molecule to control phenazine antibiotic production in the wheat rhizosphere (D. W. Wood and L. S. Pierson III, Gene 168:49-53, 1996). In this study, we demonstrate that naturally co-existing, non-isogenic bacterial populations interact with strain 30-84 at the level of gene expression via the exchange of diffusible signals on wheat roots. Wheat plants from three geographic locations were used to generate a random library of 700 rhizobacterial isolates. Roughly 8% of the isolates from each location restored phenazine gene expression to an AHL-deficient strain of 30-84 in vitro. Five of these isolates were further tested for their ability to influence gene expression of an AHL-deficient reporter of strain 30-84 on wheat roots. All five, isolated from different geographic locations, restored phenazine gene expression by the reporter to wild-type levels. This suggests that in vitro assays can identify bacterial isolates with the potential to influence phenazine expression in strain 30-84 via AHLs on wheat roots. The occurrence of such strains in all fields sampled suggests that AHL-mediated communication is a common occurrence in the wheat rhizosphere