1. Department of Microbiology; University of Zurich; CH-8008 Zurich Switzerland
2. Department of Microbiology; University of Ghent; 9000 Gent Belgium
3. Institute for Pharmaceutical Biology; University of Bonn; 53115 Bonn Germany
4. Plant Conservation and Population Biology; KU Leuven; 3001 Leuven Belgium
5. National Botanic Garden of Belgium; 1860 Meise Belgium