Transcriptomic Identification of Wheat AP2/ERF Transcription Factors and Functional Characterization of TaERF-6-3A in Response to Drought and Salinity Stresses

Abstract

AP2/ERF (APETALA2/ethylene responsive factor) is a family of plant-specific transcription factors whose members are widely involved in many biological processes, such as growth, development, and biotic and abiotic stress responses. Here, 20 <i>AP2/ERF</i> genes were identified based on wheat RNA-seq data before and after drought stress, and classified as AP2, ERF, DREB, and RAV. The analysis of gene structure revealed that about 85% of <i>AP2/ERF</i> family members had lost introns, which are presumed to have been lost during the formation and evolution of the wheat genome. The expression of 20 <i>AP2/ERF</i> family genes could be verified by qRT-PCR, which further supported the validity of the RNA-seq data. Subsequently, subcellular localization and transcriptional activity experiments showed that the ERF proteins were mainly located in the nucleus and were self-activating, which further supports their functions as transcription factors. Furthermore, we isolated a novel <i>ERF</i> gene induced by drought, salt, and cold stresses and named it <i>TaERF-6-3A</i>. <i>TaERF-6-3A</i> overexpression increased sensitivity to drought and salt stresses in <i>Arabidopsis</i>, which was supported by physiological and biochemical indices. Moreover, the expression of stress- and antioxidant-related genes was downregulated in <i>TaERF-6-3A</i>-overexpressing plants. Overall, these results contribute to the further understanding of the <i>TaERF-6-3A</i> gene function in wheat.