SHORT INTERNODE (SHI)-Related Sequence Genes in Bread Wheat: Molecular Characterization and Expression Analyses...

SHORT INTERNODE (SHI)-related sequence (SRS) transcription factors are plant-specific zinc-finger proteins increasingly implicated in growth and abiotic stress responses. Despite their diverse vital role in plants, they are largely unexplored in bread wheat. In this study, we identified 15 TaSRS genes and classified them into five homoeologous groups in the bread wheat genome. Each TaSRS protein consisted of conserved RING-like zinc-finger and IGGH domains. The synteny and phylogenetic analyses provided insight into the evolutionary divergence and conservation of TaSRS proteins. Promoter analysis revealed the presence of stress-responsive cis-regulatory elements along with various transcription factor binding sites, indicating their plausible roles in drought and salinity stress responses and signalling. Additionally, the predicted regulation of a few TaSRS genes through certain miRNAs involved in hormone and stress responses, plant development, and nutrient uptake suggested their diverse functions. In silico protein-protein interaction and gene ontology analyses further anticipated an association of TaSRS proteins with organ development and hormone and stress response. High-throughput transcriptomic profiling revealed differential expression of TaSRS genes across various vegetative and reproductive stages and abiotic stress conditions. The qRT-PCR analyses confirmed the stress-responsive role of TaSRS1-1D, TaSRS2-3D, TaSRS4-7A, and TaSRS5-7A under drought and salinity conditions. These results indicated the potential role of TaSRS genes in stress adaptation and opened up opportunities for their detailed functional characterization and applications in the development of salinity and drought resilience in crops.