1. Biological Science Research Center, Southwest University, Chongqing 400715, China
2. Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA 94710, USA
3. USDA-ARS, Plant Gene Expression Center, Albany, CA 94706, USA
4. USDA-ARS, Western Regional Research Center, Crop Improvement and Genetics Research Unit, Albany, CA 94706, USA