This study was supported by the National Natural Science Foundation of China (No. 31772642, 31672457), the International Partnership Program of the Chinese Academy of Sciences (161343KYSB20160008), the National Key Research and Development Program of China (2018YFD0501003, 2016YFD0500504, 2016YFD0501201), the Local Science and Technology Development Project Guided by the Central Government (YDZX20184300002303, 2018CT5002), the Hunan Provincial Science and Technology Department (2017NK2322, 2018TP1031), and the China Postdoctoral Science Foundation (2018M632963). The authors also acknowledge the CAS-TWAS Presidents Fellowship for international PhD students.