Molecular Characterization of DREB Gene(s) from different Tomato Genotypes

Abstract

Dehydration Responsive Element Binding (DREB) gene family assists in the defense mechanisms against environmental stresses. Identification and characterization of DREB genes family has been performed in many plants, but there is limited information available in Solanum lycopersicum. Total 58 SlDREB genes were discovered with the confirmation of conserved domain and the presence of amino acid at 14th position. Phylogenetic analysis revealed the presence of five subgroups in tomato, excluding A3 class due to zero homology with A3 members of Arabidopsis. identification and isolation of SlDREB7 and SlDREB18 proved their presence through PCR amplification. Further, results of intron-exon organization and motif analysis in each SlDREB protein proved more consistency with phylogenetic tree, as members belong to same class have similar gene structure and conserved motifs. Genomic localization and gene duplication events demonstrated the random distribution of SlDREB genes on 12 chromosomes and tandem and segmental duplication events occurred in 15 pairs of SlDREB genes. Synteny analysis revealed 32 and 47 orthologues of SlDREB genes in Arabidopsis and Solanum tuberosum. About 103 cis regulatory elements were discovered that involved in the regulation of light responsiveness, promotor binding sites, hormonal modifications, cellular development, defence against biotic and abiotic stresses. Gene ontology revealed the role of SlDREB proteins in several biological and molecular pathways such as in defense response, regulation of transcription, water deficiency, cutin biosynthesis and wax metabolic processes. Subcellular localization showed the primary presence of SlDREB genes in nucleus and variable abundance in 13 other organelles. Prediction of secondary and tertiary structures. Analysis of catalytic sites and disordered regions proved the structural diversity and functional versatility of SlDREB proteins. Further, assessments conducted to access interactive networks of SlDREB proteins with other potential proteins revealed the role of SlDREB genes in the regulation of complex signaling cascades. This comprehensive research provides deep insight into extensive identification, molecular and functional characterization of SlDREB genes in abiotic stress that can be used for the production of abiotic tolerant tomato varieties through genetic engineering. Keywords: Solanum lycopersicum, Phylogenetics, Gene ontology, Catalytic sites, Homology modelling, Protein interactions