Department of Molecular Biology, Max Planck Institute for Infection Biology, D-10117, Berlin, Germany.|Genomics of Gene Expression Lab, Centro de Investigación Príncipe Felipe, 46012, Valencia, Spain and Microbiology and Cell Science Department, Institute for Food and Agricultural Research, University of Florida at Gainesville, FL 32611-0700, USA.|Department of Molecular Biology, Max Planck Institute for Infection Biology, D-10117, Berlin, Germany.