1. BIOGECO, INRA, Univ. Bordeaux, 33615 Pessac, France;
2. BIOGECO, INRA, Univ. Bordeaux, 33610 Cestas, France
3. Bioresources Unit, Department of Health and Environment, AIT Austrian Institute of Technology GmbH, 3430 Tulln, Austria
4. INRA, Unité de Recherche de Pathologie Végétale, 84143 Montfavet, France