Exploring the gene regulatory networks of WRKY family in grapevine (Vitis vinifera  L.) using DAP-Seq

The recent development of regulatory genomics has raised increasing interest in plant research since transcriptional regulation of genes plays a pivotal role in many biological processes. By shedding light on the target genes of the various transcription factors (TFs), it is therefore possible to infer the influence they exert on the different molecular mechanisms. In this regard, the attention was focused on WRKYs, a family of TFs almost exclusively found in plant species. In grapevine, WRKYs are involved in several biological processes, playing a key role in berry development, hormonal balance and signalling, biotic and abiotic stresses responses, and secondary metabolites biosynthesis. In this study, DAP-Seq was used to investigate the regulatory activity of the whole WRKY family in gDNA from young leaves of Cabernet Franc. This approach allowed the definition of the WRKYs cistrome (i.e., the set of bound genes). 46 out of 59 WRKYs gave results, outlining a total number of 674,407 binding events along whole grapevine genome, of which 459,791 (68%) are localized in the perigenic region, according to its intense regulatory activity. Cistrome maps were integrated with gene centred co-expression networks based on a large transcriptomics dataset, and with the results of an ATAC-Seq. This allowed to isolate some High Confidence Targets, characterized by high degree of co-expression with the related TF and laying down in genomic regions of open chromatin. The networks generated can be used to provide a complete regulatory map of WRKY family, shedding light on its biological role in grapevine.