Abstract:
Dehydration Responsive Element Binding (DREB) gene family plays a crucial role as transcription regulators and enhances plant tolerance to abiotic stresses. Although the DREB gene family has been identified and characterized in many plants, knowledge about it in Solanum tuberosum (Potato) is limited. In the present study, StDREB gene family was comprehensively analyzed using bioinformatics approaches. A total of 66 StDREB genes were identified through genome wide screening of Potato genome based on the AP2 domain architecture and amino acid conservation analysis (Valine at position 14th). Phylogenetic analysis divided them into six distinct subgroups (A1-A6). The categorization of StDREB genes into six subgroups was further supported by gene structure and conserved motif analysis. Potato DREB genes were found to be distributed unevenly across 12 chromosomes. Gene duplication proved that StDREB genes experienced tandem and segmental duplication events which led to the expansion of the gene family. The Ka/Ks ratios of the orthologous pairs also demonstrated the StDREB genes were under strong purification selection in the course of evolution. Interspecies synteny analysis revealed 45 and 36 StDREB genes were orthologous to Arabidopsis and Solanum lycopersicum, respectively. The in-silico promoter analysis revealed variable sets of cis-elements and functional diversity with the predominance of light-responsive, development-related, abiotic stress-responsive and hormone-responsive elements in StDREBs. Subcellular localization indicated that StDREB genes were predominantly located within the nucleus and the StDREB family’s major function was DNA binding according to gene ontology (GO) annotation. Moreover, six proteins were selected from StDREB subgroups A1-A6 for secondary structure analysis and three dimensional protein modeling followed by model validation through Ramachandran Plot. The present study also predicted pocket binding sites to gain insights into the structural flexibility of StDREB proteins. This study provides a comprehensive and systematic understanding of precise molecular mechanism and functional characterization of StDREB genes in abiotic stress responses and will lead to improvement in S. tuberosum.
