Locus-aware characterization of wheat LOG-related genes and their transcriptional responses to abiotic stress.

LONELY GUY (LOG) phosphoribohydrolases catalyze the final direct step in cytokinin activation, but their composition and stress-responsive regulation remain difficult to resolve in allohexaploid wheat because homoeology, alternative transcript models and annotation errors inflate apparent gene-family size. We conducted a locus-aware genome-wide analysis integrating comparative phylogenetics, chromosomal distribution, exon-intron and conserved-motif architecture, predicted subcellular localization, promoter cis-elements, Gene Ontology enrichment, protein-association and miRNA-target networks, public stress transcriptomes with reconstructed study metadata, and RT-qPCR validation in the contrasting IPK accessions TRI4563 and TRI3664 under 20% PEG-6000 and 40 °C heat stress. The comparative dataset contained 100 sequence models from wheat, barley, rice and Arabidopsis. Sixty-one wheat transcript/protein models represented 30 nonredundant source-annotation loci distributed across 13 chromosomes from homoeologous groups 1-5. Annotation review distinguished 50 cytokinin-phosphoribohydrolase-annotated models, six YJL055W-like models and five atypical/ambiguous models. Direct audit of the supplied wheat protein sequences showed that 59 of 61 models retained the canonical plant short motif PGGYGTxxE; TaLOG37 and TaLOG38 carried the variant PGGHGTLEE. Predicted localization was dominated by the cytosol, mitochondria and chloroplasts, while promoter, GO, STRING and miRNA analyses were interpreted as computational support rather than functional proof. Public expression profiles were traced to defined wheat genotypes, tissues, treatments and study accessions and revealed gene-specific responses. Reanalysis of the supplied biological-replicate relative-expression data confirmed the strongest tolerant-genotype contrasts for TaLOG7 and TaLOG11 at selected heat and PEG time points, while TaLOG22 and TaLOG26 showed distinct transient or repressive patterns. Parallel antioxidant-gene expression supports only an expression-level coordination hypothesis because cytokinin concentrations, LOG activity, ROS abundance and antioxidant enzyme activities were not measured. These findings provide a model-, locus- and sequence-aware framework for wheat LOG biology and prioritize TaLOG11 and the YJL055W-like TaLOG7 for homoeologue-specific assays, hormone profiling and functional genetic validation.