Isolation and characterization of a soybean transcription factor, GmDof4.2, improves transgenic tobacco drought tolerance

Abstract DNA binding with one finger (Dof) is a plant-specific transcription factor (TF) that has a key role in seed development and germination, light-mediated control, and plant responses to biotic and abiotic stressors. Herein, we aimed to evaluate the role of the soybean Dof -TFs in plant resistance genetic engineering breeding. In this study, GmDof4.2 was isolated from the soybean. GmDof4.2 in soybean seedlings responded to drought, salt, heat, and cold stressors, according to the results of real-time fluorescence quantitative PCR (qPCR). GmDof4.2 protein had a 59-amino-acid Dof domain with a CX2CX21CX2C motif and four conserved cysteine (Cys) residues, according to the predicted amino acid sequence. The GmDof4.2 protein shared the most genetic similarities with the Cajanus cajan CcDof4 protein. Seven cis-elements associated with stress or hormone induction, as well as two TF binding sites, were found in the GmDof4.2 promoter region. GmDof4.2 protein bound specifically to the AAAG motif in vivo according to the results of yeast one-hybrid. Moreover, the overexpression of GmDof4.2 resulted in higher soluble carbohydrates content and proline content and lower relative electrolyte leakage and malondialdehyde content in transgenic tobacco than in wild-type (WT) tobacco under drought stress. Furthermore, the expression levels of nine stress-related genes were considerably greater in transgenic tobacco than in WT tobacco. The underlined data suggested that the GmDof4.2 improved drought tolerance in transgenic tobacco.