1. NWAFU-PU Joint research Center; State Key Laboratory of Crop Stress Biology for Arid Areas; College of Plant Protection; Northwest A&F University; Yangling Shaanxi 712100 China
2. Department of Biochemistry; Purdue University; West Lafayette IN 47907 USA
3. Department of Botany and Plant Pathology; Purdue University; West Lafayette IN 47907 USA