Identification of the CBF Gene Family in Wheat and <i>TaCBF14B</i> Could Enhance the Drought Tolerance of <i>Arabidopsis thaliana</i>

Drought stress is a devastating natural stress that threatens crop productivity and quality. Mitigating the adverse effects of drought stress on wheat is a key object in agriculture. C-repeat binding transcription factor/DROUGHT RESPONSE ELEMENT BINDING FACTOR 1 (CBF/DREB1) transcription factors are well known for their role in cold acclimation. However, the involvement of <i>CBF</i> genes in drought stress and the mechanisms underlying their function remain poorly understood. In this study, 81 <i>CBFs</i> were identified in wheat, which were further clustered into four distinct lineages based on phylogenetic analysis. Chromosomal localization indicated that most <i>CBF</i> genes were dispersed across chromosome 5. We identified three homoeologous genes (<i>TaCBF14A</i>, <i>TaCBF14B</i>, and <i>TaCBF14D</i>) that were simultaneously upregulated under drought stress based on RNA-seq analysis. According to the high expression after drought stress, <i>TaCBF14B</i> was selected for further functional analysis. Subcellular localization and transcriptional activation activity analysis indicated that <i>TaCBF14B</i> likely functions as a transcription factor involved in drought stress tolerance. Overexpression of <i>TaCBF14B</i> in <i>Arabidopsis</i> enhanced the primary root growth by 13.49% (OE1), 12.56% (OE2), and 19.53% (OE3) under 200 mM mannitol treatment, and 21.65% (OE1), 16.63% (OE2), and 28.13% (OE3) under 250 mM mannitol treatment compared to WT. Meanwhile, the water loss rate of transgenic lines was 56% in WT leaves, but only 44%, 50%, and 40% in OE1, OE2, and OE3 lines, respectively. Compared to the wild type, POD activities of OE1, OE2, and OE3 were significantly increased by 42.94%, 29.41%, and 62.52%, respectively. And the Pro activities in OE1, OE2, and OE3 were significantly increased by 16.33%, 5.18%, and 29.09%, respectively, compared to the wild type. Additionally, the MDA content in OE1, OE2, and OE3 was significantly reduced by 40.53%, 15.81%, and 54.36%, respectively. Further analysis showed that the transgenic lines were hypersensitive to abscisic acid (ABA), and exhibited increased expression of <i>AtABI3</i>. We speculate that <i>TaCBF14B</i> plays an important role in enhancing drought tolerance. In summary, our findings provide new insights into the functional roles of <i>CBF</i> genes in drought stress tolerance.