Integrated genome-wide and expression analysis of YABBY genes in Triticum aestivum under PEG-induced osmotic, cold and combined stress.

YABBY transcription factors are plant-specific regulators of organ polarity, lamina outgrowth and reproductive development. In wheat (Triticum aestivum L.), previous genome-wide studies identified core TaYABBY loci and described their expression across tissues and selected stresses. Here, we re-examined YABBY-associated protein models and integrated phylogenetic, structural, promoter, public transcriptomic and qRT-PCR analyses, with emphasis on cold and PEG-induced osmotic stress. We recovered 60 TaYABBY protein-model entries, which correspond to 25 unique wheat gene IDs, including multiple transcript/protein models for 14 loci, thereby reconciling our entry number with earlier reports of approximately 20 wheat YABBY genes. Nineteen entries shorter than 100 amino acids and one HMG-box-only entry lacking explicit YABBY annotation were flagged as partial or low-confidence and excluded from strong functional inference. Phylogenetic analysis grouped TaYABBY candidates with barley, rice, maize, sorghum and Arabidopsis homologs into the canonical FIL/YAB3, YAB2, INO and CRC/DL subfamilies, supporting broad family conservation. Promoter analysis of 1-kb upstream regions identified light-, hormone- and stress-related motifs, including ABRE, MBS and MeJA/SA-responsive elements, which are reported as motif-composition observations rather than enriched regulatory modules. Public expVIP RNA-seq data suggested stress-responsive expression for subsets of TaYABBY entries. qRT-PCR of six prioritized candidates, TaYABBY4, TaYABBY24, TaYABBY27, TaYABBY38, TaYABBY44, and TaYABBY50, revealed time-dependent regulation under PEG-6000, cold and combined PEG + cold treatments, with several genes showing stronger induction under combined stress. These patterns indicate transcriptional responsiveness, but not direct evidence of stress-tolerance function. Overall, this revised study provides a curated TaYABBY resource and prioritizes candidates for future functional validation under controlled osmotic and cold stress conditions.