Maize Transcription Factor ZmHsf28 Positively Regulates Plant Drought Tolerance

Abstract

Identification of central genes governing plant drought tolerance is fundamental to molecular breeding and crop improvement. Here, maize transcription factor <i>ZmHsf28</i> is identified as a positive regulator of plant drought responses. <i>ZmHsf28</i> exhibited inducible gene expression in response to drought and other abiotic stresses. Overexpression of <i>ZmHsf28</i> diminished drought effects in Arabidopsis and maize. Gene silencing of <i>ZmHsf28</i> via the technology of virus-induced gene silencing (VIGS) impaired maize drought tolerance. Overexpression of <i>ZmHsf28</i> increased jasmonate (JA) and abscisic acid (ABA) production in transgenic maize and Arabidopsis by more than two times compared to wild-type plants under drought conditions, while it decreased reactive oxygen species (ROS) accumulation and elevated stomatal sensitivity significantly. Transcriptomic analysis revealed extensive gene regulation by <i>ZmHsf28</i> with upregulation of JA and ABA biosynthesis genes, ROS scavenging genes, and other drought related genes. ABA treatment promoted <i>ZmHsf28</i> regulation of downstream target genes. Specifically, electrophoretic mobility shift assays (EMSA) and yeast one-hybrid (Y1H) assay indicated that <i>ZmHsf28</i> directly bound to the target gene promoters to regulate their gene expression. Taken together, our work provided new and solid evidence that <i>ZmHsf28</i> improves drought tolerance both in the monocot maize and the dicot Arabidopsis through the implication of JA and ABA signaling and other signaling pathways, shedding light on molecular breeding for drought tolerance in maize and other crops.