Interactions between the biocontrol agents Clonostachys rosea IE 726 and Pseudomonas chlororaphis PCL 1391 against tomato foot and root rot caused by Fusarium oxysporum f. sp. radicis - lycopersici Influence of fungicides on the growth of the fungus Clonostachys rosea IE726

• Published in: Phytopathologia mediterranea Vol. 48; no. 2; p. 344
• Main Authors: Tzelepis, G, Lagopodi, AL
• Format: Journal Article
• Language: English
• Published: 01.08.2009
• Subjects: Clonostachys rosea; Fusarium oxysporum; Lycopersicon esculentum; Pseudomonas chlororaphis
• ISSN: 0031-9465

The aim of this study was to investigate the interactions between the fungus Clonostachys rosea IK 726 and the bacterium Pseudomonas chlororaphis PCL 1391 against the phytopathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici (F.o.r.l.) that causes tomato foot and root rot. Results of ire vitro experiments, in dual cultures wtth P. chlororaphis PCL 1391 and F.o.r.l. and with P. chlororaphis PCL 1391 and C. rosea IK 726 showed production of an inhibition zone at the fungal colonies in the vicinity of the bacterium. Isolation of the antibiotic phenazine-1-carboxamide, which is produced by this bacterium, by Thin Layer Chromatography, followed by a bioassay demonstrated that this antibiotic inhibits the growth of both fungi. However, results of in planta experiments in a gnotobiotic system showed that, there was a synergistic effect between the biocontrol agents against the pathogen since their combined application reduced the disease index significantly, compared to the positive control and the plants in which these biological agents were applied separately. Results of in planta experiments in pots have shown that the combined application of the biological agents reduced significantly the disease index, in comparison to positive control, but not in comparison to plants on which these biological agents were applied separately. A further microscopy study will unravel more aspects regarding the interaction between the three microorganisms in the tomato rhizosphere.