1. Department of Soil Microbiology and Symbiotic Systems; Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas (EEZ-CSIC); Profesor Albareda 1 18008 Granada Spain
2. Department of Environmental Biology, Agricultural Chemistry and Biology, Group CMI Roullier, Faculty of Sciences; University of Navarra; 31009 Navarra Spain
3. Laboratory of Plant Physiology; Wageningen University; Droevendaalsesteeg 1 6708 PB Wageningen The Netherlands
4. Plant Research International, Bioscience; Droevendaalsesteeg 1 6708 PB Wageningen The Netherlands