1. Unité Mixte de Recherche INRA–UHP 1136 ‘Interactions Arbres/Microorganismes’, Centre de Recherches de Nancy, 54280 Champenoux, France;
2. These authors contributed equally to this work
3. INRA Rennes, Unité Mixte de Recherche BiO3P, BP 35327, 35653 Le Rheu Cedex, France;
4. Dept. of Biological Sciences, University of Alabama, Huntsville, AL 35899, USA;