Abiotic stresses and biotic stresses affect many economical crops and reduce their yield and trigger stress responses . Regulation of stresses occur at cellular, biochemical, physiological and molecular level. A number of stress responsive genes and proteins associated with signaling at molecular level have been identified and characterized . Transcription factors are DNA binding proteins that initiate transcription and bind themselves to cis-regulatory elements. The functional and evolutionary similarities among different TFs have led to their classification into various families including APETALA2/ethylene response factor (AP2/ERF), AP2/ERF, WRKY, FAR1, DREB etc . AP2/ERF transcription factor family play a crucial role in expression of genes, related to stress responses, reproduction, defense, and hormone secretion . Over the past several years, there has been an increasing interest in the study of functional and structural characteristics of AP2/ERF. AP2/ERF superfamily emerged by horizontal transfer from bacteria/viruses to plants . First discovered in Arabidopsis thaliana, the proteins comprises of 60 to 70 amino acids . These genes were cloned or replicated in tobacco plants initially . Currently, AP2/ERF gene family have been recognized in several species including wheat, barley, foxtail millet, sorghum, maize, barley, soya bean, grape, poplar, moso bamboo and among most of the members of the grass family [8–11].AP2, ERF and RAV based on the domain observed among these proteins. AP2 family have two AP2/ERF domains and is majorly involved in the plant developmental process like leaf formation and development of, flowers, embryos, ovules and fruits . It also consists of two sub families AP2 and ANT . ERF family has only one AP2/ERF domain and is involved in ethylene signal transduction. [14, 15], pathogen-stimuli and gene expression . Recently, ERF genes have been studied in maize . In RAV family, two structural domains are present on AP2/ERF and one B3 domain also present in other transcription factors.  Moreover, RAV show hormonal responses to ethylene and brassinosteroid .
ERF family is further split up into two subfamilies: the CBF (C-repeat)/DREB (dehydration response element binding) and ERF (Ethylene responsive factors) . ERF subfamilies bind to the GCC box (AGCCGCC) , where G2, G5 and C7 are the core and crucial residues [21–24]. The 3-D analysis of AP2/ERF protein domain depict 3 anti-parallel beta-sheet and one alpha-helix [22–24]. On the other hand, ERF transcription factor proteins are involved in various signaling cascades involving complex protein-protein interactions (PPIs) forming protein networks driving various signaling pathways. PPIs are vital for a variety of cellular processes, thereby, making the apprehension of PPIs a crucial factor for perception of cell physiology in normal states and diseased states. [25–30]. Protein-protein interaction networks (PPIN) are mathematical depictions of the physical connections between various proteins within the cell. Globally, wheat demand is increasing with increase in world population and food demands .Biotic and abiotic stresses affect wheat production to a greater extent. Many TF have been studied in wheat that respond to pathogen related attack and tolerating freezing temperatures [31–32].To responses. To date, there is no report that represent detailed analysis of structure and function prediction of ERF proteins in wheat using in silico approaches. Genome-wide analysis of a family is relatively effective approach to classify and differentiation of plant gene or proteins functions, facilitating the study of the phylogeny of genes and genomes.
Though, AP2/ERF proteins have been thoroughly studied in various plant families, the current research provides detailed structural analysis and protein interaction network of ERF proteins involved in stress regulation. Present study is mainly focused on genome-wide analysis of ERF subfamily and protein-protein interaction network analysis in Triticum aestivum. Phylogenetic evolutionary studies, gene structure analysis, protein-protein interaction network analysis, gene ontology has been incorporated. This prediction-based study would help in providing an insight for future strategies and research for functional analysis and to design wet lab-based experiments.