Genome-Wide Identification and Hormone-Induced Expression Analysis of the Anthocyanidin Reductase Gene Family in Sainfoin (Onobrychis viciifolia Scop.)

Sainfoin (Onobrychis viciifolia Scop.) is an important legume forage. Its anthocyanidin reductase (ANR) catalyzes the conversion of anthocyanins to epicatechins. This conversion reaction is not only a key step in the biosynthesis of proanthocyanidins (PAs) but also directly influences both forage quality and stress resistance. Here, we systematically identified 67 ANR gene family members in autotetraploid sainfoin for the first time. Using bioinformatics approaches, we analyzed gene structure, conserved domains, motifs, and cis-regulatory elements of the identified ANR genes. In this study, phylogenetic analysis revealed that the ANRs clustered into 11 distinct clades, with genes within the same clade predominantly originating from closely related species within the same family. Significant collinearity with Arabidopsis thaliana, Glycine max, Cicer arietinum, and Medicago truncatula further revealed the conserved evolutionary path of this gene family. RT-qPCR analysis showed differential expression patterns of OvANRs in root, stem, and leaf tissues. For instance, OvANR19 was significantly induced by abscisic acid (ABA) and methyl jasmonate (MeJA), with its expression upregulated by 79.7-fold and 3.8-fold in roots and by 16.2-fold and 31.3-fold in leaves. Furthermore, subcellular localization analysis confirmed that representative ANR proteins were localized in the cytoplasm. This study lays a foundation for molecular breeding aimed at enhancing stress resistance and forage quality in sainfoin.