WUSCHEL-related homeobox ( WOX ) genes belong to the homeobox superfamily, are plant-specific and play vital functions in the growth and development. Herein, we identified a total of 43 TaWOX genes in the allohexaploid (AABBDD) genome of Triticum aestivum L . These genes were distributed on the various chromosomes of each subgenome (A, B and D). The phylogenetic analysis showed the clustering of TaWOXs into three clades: ancient, intermediate and modern or WUS. The gene and protein structures including exon/intron organization, intron phases, and domain and motif distribution were found to be conserved in each phylogenetic clade. The subcellular localization was predicted as nuclear. The Ka/Ks analyses suggested the purifying selection of paralogous genes. The differential expression profiling of various TaWOXs in numerous tissue developmental stages and different layers of grains suggested their role in growth and development. Moreover, a few genes exhibited modulated expression during abiotic and biotic stress conditions, which revealed their roles in stress response. The occurrence of various cis- acting regulatory elements further confirmed their role in plant development and stress tolerance. The co-expression analyses suggested the interactions of these genes with other genes, involved in various processes including plant development, signalling and stress responses. The present study reported several characteristic features of TaWOX s genes that can be useful for further characterization in future studies.

The three amino acid loop extension (TALE) genes of the homeobox superfamily are responsible for numerous biological functions in plants. Herein, we identified a total of 72 TaTALE genes in the allohexaploid genome of bread wheat (Triticum aestivum L.) and performed a comprehensive investigation for gene and protein structural properties, phylogeny, expression patterns, and multilevel gene regulations. The identified TaTALE proteins were further classified into two groups, TaBLHs and TaKNOXs, which were tightly clustered into the phylogeny. The negative Ka/Ks ratio of duplicated genes suggested purifying selection pressure with confined functional divergence. Various signature domains and motifs were found conserved in both groups of proteins. The occurrence of diverse cis-regulatory elements and modulated expression during various developmental stages and in the presence of abiotic (heat, drought, salt) and two different fungal stresses suggested their roles in development and stress response, as well. The interaction of TaTALEs with the miRNAs and other development-related homeobox proteins also suggested their roles in growth and development and stress response. The present study revealed several important aspects of TaTALEs that will be useful in further functional validation of these genes in future studies.