INTERACTIONS BETWEEN PSEUDOMONAS-FLUORESCENS BIOCONTROL AGENTS AND GLOMUS-MOSSEAE, AN ARBUSCULAR MYCORRHIZAL FUNGUS, WITHIN THE RHIZOSPHERE

Interactions between Pseudomonas fluorescens biocontrol agents and Glo mus mosseae: an arbuscular mycorrhizal fungus, were studied. The bioco ntrol agents included the genetically modified strains CHA96 and CHA0 pME3424 which produced enhanced levels of antifungal compounds. Tomato (Lycopersicum esculentum) and leek (Allium porrum) host plants were g rown in sterile Terra-Green (calcined attapulgite clay) with limited n utrients. Mycorrhizal activity was indicated by shoot dry weight and p hosphorus content. In all experiments, plants grown in the presence of G. mosseae had a significantly higher shoot dry weight than those gro wn in the absence of G. mosseae. Colonisation and activity of G. mosse ae was unaltered in the presence of P. fluorescens isolates and presen ce of G. mosseae increased the population of P. fluorescens in the rhi zosphere. (C) 1998 Published by Elsevier Science B.V. All rights reser ved.