Identification of a novel transcription factor under long-term drought resistance in highland barley: a DNA affinity purification sequencing-based transcriptomic analysis

Abstract

AbstractStress emanating from drought condition is one of the inevitable conditions that occurs in many environments and spread across borders and results in severe hindrance to the morphology, physiology, biochemistry and molecular attributes of plants. Highland barley drought tolerance has been demonstrated to be a polygenic related characteristic and genetic composition that can assist in dissecting the gene network(s) controlling the drought tolerance needs to be adequately understood. DNA affinity purification sequencing (DAP-seq) has been shown to contribute to ways of making pure some of the protein with rare sequence-specific DNA binding and can help understand the molecular dynamics in barley under varying exposure time to drought. The present study aimed at identifying novel transcription factors (TFs) in highland barley that are key in drought resistance through DAP-seq-based transcriptomic analysis. The experimental design included two hulless barley accessions; drought-resistant Sheera 10 (X) and drought-sensitive 5171–7 (W), that were both subjected to short-term (4 h) and long-term (48 h) exposure to drought (T1 and T5, respectively), with the control group (CK) involving not subjecting the two accessions to any treatment. Through transcriptome analysis, one candidate transcription factor (GATA family; (bHLH, MYB-related, GARP-G2-like, bZIP, HB-HD-ZIP, C2H2, SET, mTERF, AP2/ERF-ERF, ARID, NAC, GARP-ARR-B, C2C2-GATA, FAR1, Trihelix, NF-YB, B3 and AUX/IAA) was found. The motif obtained was found to be consistent with GATA transcription factor. The DAP-seq highlighted the differential expression target gene which were verified by RT-qPCR. The associated genes were found to be a cluster of structural gene IP_HOR_1, IP_HOR_2 and In_HOR locus. Through RT-qPCR, it was also proved that the gene expressions were indeed upregulated. The TF HOVUSG2784400 was confirmed to be responsible to drought stress under long-term exposure, which regulates the differential expression of the genes, thereby improving the drought resistance of barley. Graphical Abstract