1 Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, United States of America.
2 Department of Microbiology and Plant Pathology and Institute for Integrative Genome Biology, University of California, Riverside, California, United States of America.
3 Department of Ecology and Evolutionary Biology, University of Connecticut, Hartford, Connecticut, United States of America.
4 Department of Plant and Environmental Science, University of Copenhagen, Frederiksberg, Denmark.