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Research article - Peer-reviewed, 2010

Suppression of disease in tomato infected by Pythium ultimum with a biosurfactant produced by Pseudomonas koreensis

Hultberg Malin, Alsberg Tomas, Khalil Sammar, Alsanius Beatrix


The use of biosurfactants is a promising alternative in biological control of zoospore-producing oomycetes, which are a major plant pathogen world-wide in a wide variety of crops. Oomycetes are of particular concern in closed hydroponic cultivation systems. The present study investigated the efficacy of a biosurfactant produced by Pseudomonas koreensis and added as a crude extract against the oomycete Pythium ultimum in hydroponic tomato cultivation. A significant reduction in disease was observed. Biosurfactant addition did not affect the indigenous root microflora when evaluated as sole carbon source utilisation. Chemical analysis, using electrospray hybrid mass spectrometry (ESI-MSMS), of the biosurfactant indicated it to be lokisin, a cyclic lipopeptide. These results confirm that biosurfactants are important in developing sustainable biological control strategies for oomycetes.


Biological control; hydroponics; lokisin; oomycetes; Pseudomonas koreensis; Pythium ultimum

Published in

2010, Volume: 55, number: 3, pages: 435-444
Publisher: Springer

      SLU Authors

      • Khalil, Samar

        • Horticulture, Swedish University of Agricultural Sciences
      • UKÄ Subject classification


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