State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China (in preparation), Rice Research Institute, Sichuan Agricultural University at Wenjiang, Chengdu, 611130, China. Department of Plant Pathology and the Genome Center, University of California, Davis, California, 95616, USA. State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China (in preparation), Rice Research Institute, Sichuan Agricultural University at Wenjiang, Chengdu, 611130, China. xwchen88@163.com.