1. Emerging Pests and Pathogens Research Unit, USDA Agricultural Research Service, Ithaca, New York 14853, United States
2. Boyce Thompson Institute for Plant Research, Ithaca, New York 14853, United States
3. Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York 14853, United States
4. Department of Genome Sciences, University of Washington, Seattle, Washington 98109, United States