1. State Key Laboratory of Crop Stress Biology in Arid Areas and College of Plant Protection Northwest A&F University Yangling Shaanxi 712100 China
2. MOE Key Laboratory for Intelligent Networks & Network Security, Faculty of Electronic and Information Engineering Xi'an Jiaotong University Xi'an 710049 China
3. School of Environmental Sciences University of Guelph Guelph ON N1G 2W1 Canada
4. Department of Plant Pathology and Microbiology Iowa State University Ames IA 50011 USA