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Applied and Environmental Microbiology, June 2005, p. 3033-3040, Vol. 71, No. 6
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.6.3033-3040.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Genetic Analysis of Biosurfactant Production in Ustilago maydis

Sandra Hewald, Katharina Josephs, and Michael Bölker*

Philipps-Universität Marburg, Fachbereich Biologie, 35032 Marburg, Germany

Received 5 October 2004/ Accepted 29 December 2004

The dimorphic basidiomycete Ustilago maydis produces large amounts of surface-active compounds under conditions of nitrogen starvation. These biosurfactants consist of derivatives of two classes of amphipathic glycolipids. Ustilagic acids are cellobiose lipids in which the disaccharide is O-glycosidically linked to 15,16-dihydroxyhexadecanoic acid. Ustilipids are mannosylerythritol lipids derived from acylated ß-D-mannopyranosyl-D-erythritol. Whereas the chemical structure of these biosurfactants has been determined, the genetic basis for their biosynthesis and regulation is largely unknown. Here we report the first identification of two genes, emt1 and cyp1, that are essential for the production of fungal extracellular glycolipids. emt1 is required for mannosylerythritol lipid production and codes for a protein with similarity to prokaryotic glycosyltransferases involved in the biosynthesis of macrolide antibiotics. We suggest that Emt1 catalyzes the synthesis of mannosyl-D-erythritol by transfer of GDP-mannose. Deletion of the gene cyp1 resulted in complete loss of ustilagic acid production. Cyp1 encodes a cytochrome P450 monooxygenase which is highly related to a family of plant fatty acid hydroxylases. Therefore we assume that Cyp1 is directly involved in the biosynthesis of the unusual 15,16-dihydroxyhexadecanoic acid. We could show that mannosylerythritol lipid production is responsible for hemolytic activity on blood agar, whereas ustilagic acid secretion is required for long-range pheromone recognition. The mutants described here allow for the first time a genetic analysis of glycolipid production in fungi.

* Corresponding author. Mailing address: Philipps-Universität Marburg, Fachbereich Biologie-Genetik, D-35032 Marburg, Germany. Phone: 49-6421-282 1536. Fax: 49-6421-282 8971. E-mail: boelker{at}staff.uni-marburg.de.

Applied and Environmental Microbiology, June 2005, p. 3033-3040, Vol. 71, No. 6
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.6.3033-3040.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Mimee, B., Labbe, C., Belanger, R. R (2009). Catabolism of flocculosin, an antimicrobial metabolite produced by Pseudozyma flocculosa. Glycobiology 19: 995-1001 [Abstract] [Full Text]  
  • Klose, J., Kronstad, J. W. (2006). The Multifunctional {beta}-Oxidation Enzyme Is Required for Full Symptom Development by the Biotrophic Maize Pathogen Ustilago maydis. Eukaryot Cell 5: 2047-2061 [Abstract] [Full Text]  
  • Hewald, S., Linne, U., Scherer, M., Marahiel, M. A., Kamper, J., Bolker, M. (2006). Identification of a Gene Cluster for Biosynthesis of Mannosylerythritol Lipids in the Basidiomycetous Fungus Ustilago maydis. Appl. Environ. Microbiol. 72: 5469-5477 [Abstract] [Full Text]  
  • Hogan, D. A. (2006). Talking to themselves: autoregulation and quorum sensing in fungi.. Eukaryot Cell 5: 613-619 [Full Text]  


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