This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by de Souza, J. T. Articles by Raaijmakers, J. M. Search for Related Content PubMed PubMed Citation Articles by de Souza, J. T. Articles by Raaijmakers, J. M. Agricola Articles by de Souza, J. T. Articles by Raaijmakers, J. M.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, December 2003, p. 7161-7172, Vol. 69, No. 12
0099-2240/03/$08.00+0     DOI: 10.1128/AEM.69.12.7161-7172.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

Biochemical, Genetic, and Zoosporicidal Properties of Cyclic Lipopeptide Surfactants Produced by Pseudomonas fluorescens

Laboratory of Phytopathology, Department of Plant Sciences, Wageningen University, 6709 PD Wageningen,¹ Section Flower Bulbs, Applied Plant Research, 2160 AB Lisse,² Wageningen NMRCentre, Wageningen University, 6700 ET Wageningen,³ Natural Products Chemistry Group, Laboratory of Organic Chemistry, Wageningen University, 6703 HB Wageningen, The Netherlands⁴

Received 5 June 2003/ Accepted 4 September 2003

Zoospores play an important role in the infection of plant and animal hosts by oomycetes and other zoosporic fungi. In this study, six fluorescent Pseudomonas isolates with zoosporicidal activities were obtained from the wheat rhizosphere. Zoospores of multiple oomycetes, including Pythium species, Albugo candida, and Phytophthora infestans, were rendered immotile within 30 s of exposure to cell suspensions or cell culture supernatants of the six isolates, and subsequent lysis occurred within 60 s. The representative strain SS101, identified as Pseudomonas fluorescens biovar II, reduced the surface tension of water from 73 to 30 mN m^-1. The application of cell suspensions of strain SS101 to soil or hyacinth bulbs provided significant protection against root rot caused by Pythium intermedium. Five Tn5 mutants of strain SS101lacked the abilities to reduce the surface tension of water and to cause lysis of zoospores. Genetic characterization of two surfactant-deficient mutants showed that the transposons had integrated into condensation domains of peptide synthetases. A partially purified extract from strain SS101 reduced the surface tension of water to 30 mN m^-1 and reached the critical micelle concentration at 25 µg ml^-1. Reverse-phase high-performance liquid chromatography yielded eight different fractions, five of which had surface activity and caused lysis of zoospores. Mass spectrometry and nuclear magnetic resonance analyses allowed the identification of the main constituent as a cyclic lipopeptide (1,139 Da) containing nine amino acids and a 10-carbon hydroxy fatty acid. The other four zoosporicidal fractions were closely related to the main constituent, with molecular massesranging from 1,111 to 1,169 Da.

This article has been cited by other articles:

• de Bruijn, I., de Kock, M. J. D., de Waard, P., van Beek, T. A., Raaijmakers, J. M. (2008). Massetolide A Biosynthesis in Pseudomonas fluorescens. J. Bacteriol. 190: 2777-2789 [Abstract] [Full Text]  
• Timmusk, S., Grantcharova, N., Wagner, E. G. H. (2005). Paenibacillus polymyxa Invades Plant Roots and Forms Biofilms. Appl. Environ. Microbiol. 71: 7292-7300 [Abstract] [Full Text]  
• Compant, S., Duffy, B., Nowak, J., Clement, C., Barka, E. A. (2005). Use of Plant Growth-Promoting Bacteria for Biocontrol of Plant Diseases: Principles, Mechanisms of Action, and Future Prospects. Appl. Environ. Microbiol. 71: 4951-4959 [Full Text]  
• Berg, G., Zachow, C., Lottmann, J., Gotz, M., Costa, R., Smalla, K. (2005). Impact of Plant Species and Site on Rhizosphere-Associated Fungi Antagonistic to Verticillium dahliae Kleb.. Appl. Environ. Microbiol. 71: 4203-4213 [Abstract] [Full Text]  
• Islam, Md. T., Hashidoko, Y., Deora, A., Ito, T., Tahara, S. (2005). Suppression of Damping-Off Disease in Host Plants by the Rhizoplane Bacterium Lysobacter sp. Strain SB-K88 Is Linked to Plant Colonization and Antibiosis against Soilborne Peronosporomycetes. Appl. Environ. Microbiol. 71: 3786-3796 [Abstract] [Full Text]