Omics-Based Characterization of BTB Gene Family in T. aestivum, Reveals the Potential of TaBTB11/56/57/58 in Combined Heat and Drought Stress Regulation.

Abstract

Wheat (Triticum aestivum) is a globally important staple crop that faces increasing challenges from climate change, particularly the combined effects of heat and drought stress. The BTB (Broad Complex, Tramtrack, and Bric-à-Brac) gene family is involved in diverse biological processes, including stress responses, but its characterization in T. aestivum remains limited. This study aimed to comprehensively investigate the BTB gene family in T. aestivum and identify key genes potentially involved in resilience to abiotic stress.In the current study, we identified 62 BTB genes in T. aestivum using BLAST and Hidden Markov Model (HMM) approaches. Phylogenetic analysis classified these genes into nine subgroups based on conserved domain architecture. Gene structure analysis revealed diverse exon-intron organizations, supporting evolutionary divergence among subgroups. Chromosomal mapping demonstrated an uneven distribution of BTB genes across the A, B, and D sub-genomes, with the highest number localized on sub-genome D. Cis-regulatory element analysis highlighted the presence of multiple stress-responsive motifs, particularly those associated with heat and drought responses, i.e., ABRE, G-box, CAAT-box, TATA-box. Expression profiling using transcriptome data from two T. aestivum varieties (Atay 85 and Zubkov) revealed differential regulation of BTB gene family members under drought, heat, and combined stress conditions. Furthermore, qRT-PCR validation showed that TaBTB11, TaBTB56, TaBTB57, and TaBTB58 were consistently regulated across all three stress conditions, highlighting their potential as key targets for stress-resilient T. aestivum breeding. Furthermore, Green fluorescent protein (GFP) localization confirmed that these genes were expressed in the nucleus.This study highlights key genes, i.e., TaBTB11, TaBTB56, TaBTB57, and TaBTB58, as potential targets for marker-assisted selection and genetic improvement of T. aestivum for enhanced resilience to combined heat and drought stress.