1. Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany
2. INRA, UMR1319 Micalis, F-78350 Jouy-en-Josas, France
3. AgroParisTech, UMR Micalis, F-78350 Jouy-en-Josas, France
4. CNRS, F-78350 Jouy-en-Josas, France