A Novel Wheat C-bZIP Gene, TabZIP14-B, Participates in Salt and Freezing Tolerance in Transgenic Plants

Abstract

The group C-bZIP transcription factors (TFs) are involved in diverse biological processes, such as the regulation of seed storage protein (SSP) production and the responses to pathogen challenge and abiotic stress. However, our knowledge of the abiotic functions of group C-bZIP genes in wheat remains limited. Here, we present the function of a novel <i>TabZIP14-B</i> gene in wheat. This gene belongs to the group C-bZIP TFs and contains six exons and five introns; three haplotypes were identified among accessions of tetraploid and hexaploid wheat. A subcellular localization analysis indicated that TabZIP14-B was targeted to the nucleus of tobacco epidermal cells. A transactivation assay demonstrated that TabZIP14-B showed transcriptional activation ability and was capable of binding the abscisic acid (ABA) responsive element (ABRE) in yeast. RT-qPCR revealed that <i>TabZIP14-B</i> was expressed in the roots, stems, leaves, and young spikes and was up-regulated by exogenous ABA, salt, low-temperature, and polyethylene glycol (PEG) stress treatments. Furthermore, <i>Arabidopsis</i> plants overexpressing <i>TabZIP14-B</i> exhibited enhanced tolerance to salt, freezing stresses and ABA sensitivity. Overexpression of <i>TabZIP14-B</i> resulted in increased expression of the <i>AtRD29A</i>, <i>AtCOR47</i>, <i>AtRD20</i>, <i>AtGSTF6</i>, and <i>AtRAB18</i> genes and changes in several physiological characteristics. These results suggest that <i>TabZIP14-B</i> could function as a positive regulator in mediating the abiotic stress response.