Genome-wide identification of the GID1 genes family and expression analysis during seed germination in sainfoin (Onobrychis viciifolia)

Sainfoin ( Onobrychis viciifolia ) is a kind of leguminous plant with high feeding value. It contains a high concentration of tannin at all growth stages, which can precipitate soluble proteins that can form a large number of persistent foams in the rumen, so that ruminant livestock will not develop dilatation disease during green feeding and grazing. GID1 (Gibberellin Insensitive Dwarf1) is a key receptor gene in the gibberellin (GA) signaling pathway, playing a central regulatory role in plant growth, development, and environmental responses. In this study, 6 GID1 genes were identified in sainfoin, and the characteristics of gene family were revealed through multidimensional analyses. Physicochemical property analysis revealed obvious variations among OvGID1 genes, with molecular weight (MW) ranging from 38.93 to 39.55 kDa and isoelectric point (pI) from 6.51 to 8.37, accompanied by differences in hydrophobicity. Phylogenetic analysis classified them into three subfamilies, with the 6 genes unevenly distributed across 5 chromosomes. Promoter cis-acting element analysis detected numerous regulatory motifs associated with abiotic stress responses (LTR, MBS) and hormone regulation (ABRE, GARE-motif). Expression analysis revealed that OvGID1B2 gene was significantly upregulated under drought, while both OvGID1B2 and OvGID1C2 were significantly upregulated 48 h after low-temperature treatment. Furthermore, GA₃ treatment demonstrated dynamic expression patterns of the 6 OvGID1 genes across dry seed stage (GZ), imbibition stage (XZ), split stage (LK) and radicle emergence stage (MF) of four germination stages. This study provides a theoretical foundation for understanding the evolutionary mechanisms of the GID1 family in sainfoin and elucidates the molecular networks of GA-regulated seed germination and stress responses.