1. Netherlands Institute of Ecology, Centre for Terrestrial Ecology, Department of Plant–Microorganism Interactions, NL-6666 ZG Heteren, the Netherlands
2. Netherlands Culture Collection of Bacteria, NL-3584 CT Utrecht, the Netherlands
3. Eukaryotic Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, NL-9751 NN Haren, the Netherlands
4. Plant Protection Service, Section Bacteriology, NL-6700 HC Wageningen, the Netherlands