1 Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Seville, E41012, Spain.
2 Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland.
3 Department of Biology, Plant-Microbe Interactions, Utrecht University, Utrecht, 3584 CH, The Netherlands.
4 Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", Universidad Nacional de San Martín (IIB-UNSAM-CONICET), Buenos Aires, Argentina.
5 Molecular Microbiology Department, John Innes Centre, Norwich, UK.
6 School of Biological Sciences, University of East Anglia, Norwich, UK.