Jingying Li1, Yongwei Sun1, Jinlu Du1, Yunde Zhao2, Lanqin Xia3. 1. Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China. 2. National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China; Section of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093-0116, USA. Electronic address: yundezhao@ucsd.edu. 3. Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China. Electronic address: xialanqin@caas.cn.