Identification and functional analysis of transcription factors related to coconut(Cocos nucifera L.)endosperm development based on ATAC-seq

Coconut(Cocos nucifera L.)is a member of the palm tree family(Arecaceae)and the only living species of the genus Cocos.In this paper,the regulatory relationship pathways between multiple transcription factors and functional genes were identified by combining ATAC-seq and RNAseq in coconut endosperm at four different developmental stages(fruit after pollination:7 months,8 months,9 months and 10 months,respectively).The results indicated that the peaks detected in the promoter-TSS area accounted for the largest proportion(11.99%)in the third stage.These results suggest that the chromatin open region of cells in this period is more functional and that there are more functional genes with active transcription.In addition,a large number of potential regulatory relationships between transcription factors and functional genes were detected via bioinformatics analysis at the genomic level.Among them,CnGATA20 was predicted to be an important transcription factor with a binding site on the promoter region of the CnOLE18 gene.The regulatory pathway by which CnGATA20 positively regulates the expression of CnOLE18 was further confirmed by yeast one-hybrid,protoplast transient expression and dual-luciferase reporter system experiments.The results provide a new research strategy for exploring the regulation at both the transcriptional and posttranscriptional levels during coconut endosperm growth and development.