Uncovering transcriptional regulatory network during regeneration for boosting wheat transformation

Abstract Genetic transformation is important for gene functional study and crop breeding. Though it is available in many plant species, the transformation efficiency in wheat is generally low, which greatly restricts the genetic manipulation in wheat. Here, we use multi-omic analysis strategy to uncover core transcriptional regulatory network (TRN) driving wheat shoot regeneration and identify key factors that boost the transformation efficiency. RNA-seq, ATAC-seq and CUT&Tag were used to profile the transcriptome and chromatin dynamic during regeneration process from immature embryo of wheat variety Fielder. Sequential expression of gene clusters that mediating cell fate transition during regeneration is induced by auxin signaling, in coordination with changes of chromatin accessibility, H3K27me3 and H3K4me3 status. The TRN driving wheat shoot regeneration was built-up and 446 key transcriptional factors (TFs) occupied the core of network were identified, including functionally tested regeneration factors in other species. We further compared the regeneration process between wheat and Arabidopsis and found that DNA binding with one finger (DOF) TFs show distinct patterns in two species. Furthermore, we found that TaDOF5 . 6 ( TraesCS6A02G274000 ) and TaDOF3 . 4 ( TraesCS2B02G592600 ) can significantly improve the transformation efficiency of different wheat varieties. Thus, our data uncovers the molecular regulatory insights for wheat shoot regeneration process and provides potential novel targets for improving transformation efficiency in wheat.