RNA from embryo samples were extracted by 5M GuSCN (Invitrogen, # 20012-043), then RNA was precipitated by ethanol with the help of RNA carrier; genomic DNA from embryo samples were separated and extracted by modified microChIPseq; RNA from in vitro culture bulk cells were extracted by using Trizol and precipitated by isopropanol. Libraries of RNA samole were generated by using illumina Nextera XT DNA sample preparation kit; libraries of genomic DNA were construted by using NEBNext Ultra DNA Library Prep Kit for Illumina (NEB #7370L); libraries of bulk RNA seq were prepared by using NEBNext RNAseq library kit.