Identification of the target genes of AhTWRKY24 and AhTWRKY106 transcription factors reveals their regulatory network in Arachis hypogaea cv. Tifrunner using DAP-seq

Abstract

WRKY transcription factors (TFs) have been identified as important core regulators in the responses of plants to biotic and abiotic stresses. Cultivated peanut (Arachis hypogaea) is an important oil and protein crop. Previous studies have identified hundreds of WRKY TFs in peanut. However, their functions and regulatory networks remain unclear. Simultaneously, the AdWRKY40 TF is involved in drought tolerance in Arachis duranensis and has an orthologous relationship with the AhTWRKY24 TF, which has a homoeologous relationship with AhTWRKY106 TF in A. hypogaea cv. Tifrunner. To reveal how the homoeologous AhTWRKY24 and AhTWRKY106 TFs regulate the downstream genes, DNA affinity purification sequencing (DAP-seq) was performed to detect the binding sites of TFs at the genome-wide level. A total of 3486 downstream genes were identified that were collectively regulated by the AhTWRKY24 and AhTWRKY106 TFs. The results revealed that W-box elements were the binding sites for regulation of the downstream genes by AhTWRKY24 and AhTWRKY106 TFs. A gene ontology enrichment analysis indicated that these downstream genes were enriched in protein modification and reproduction in the biological process. In addition, RNA-seq data showed that the AhTWRKY24 and AhTWRKY106 TFs regulate differentially expressed genes involved in the response to drought stress. The AhTWRKY24 and AhTWRKY106 TFs can specifically regulate downstream genes, and they nearly equal the numbers of downstream genes from the two A. hypogaea cv. Tifrunner subgenomes. These results provide a theoretical basis to study the functions and regulatory networks of AhTWRKY24 and AhTWRKY106 TFs.