Population and pangenome analyses uncover the evolutionary dynamics of the peroxidase gene family in barley.

Gene family expansion represents an important evolutionary mechanism driving functional innovation of genes in plants. This study investigated the expansion and evolutionary patterns of the peroxidase (POD) gene family in barley (Hordeum vulgare L.), a global important cereal crop. Our analyses revealed that the expanded HvPOD genes are phylogenetically clustered and exhibit conserved exon–intron structures. These genes display tissue-specific expression profiles and are differentially regulated under various abiotic stresses, indicating functional diversification in growth and stress response. Population genetics analyses identified a mild domestication bottleneck in the HvPOD family, with clear haplotype differentiation between wild and cultivated barley. Genomic analysis of 76 genomes further classified the HvPOD repertoire into core and non-core gene sets, showing that core genes are under stronger purifying selection, consistent with essential functional conservation. These findings elucidate the evolutionary history and functional diversity of the POD family and provides genetic insights for future barley improvement.