1. Graduate Field of Microbiology, Cornell University, Ithaca, NY, USA
2. Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
3. Present address: Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA.
4. School of Integrative Plant Science, Plant Pathology & Plant-Microbe Biology, Cornell University, Ithaca, NY, USA
5. Present address: Guizhou Academy of Agricultural Sciences, Guizhou Institute of Plant Protection, Guiyang 550006, PR China.
6. Division of Plant & Soil Sciences, West Virginia University, Morgantown, WV, USA