Phylogenomic classification and synteny network analyses deciphered the evolutionary landscape of aldo–keto reductase (AKR) gene superfamily in the plant kingdom

•Plant AKRs are systematically classified into 4 groups and 14 subgroups.•Lineage-, order/family- and species-specific loss of subgroups is apparent.•Subgroups IA, IVB and IVF are flourished/diversified well during plant evolution.•AKRs relevant to important functions are evolved convergently.•This study provides comprehensive resource to exponent the AKRs research in planta. Aldo-keto reductase-domain (PF00248) containing proteins (AKRs) are NAD(P)(H)-dependent oxidoreductases of a multigene superfamily that mediate versatile functions in plants ranging from detoxification, metal chelation, potassium ion efflux to specialized metabolism. To uncover the complete repertoire of AKR gene superfamily in plants, a systematic kingdom-wide identification, phylogeny reconstruction, classification and synteny network clustering analyses were performed in this study using 74 diverse plant genomes. Plant AKRs were omnipresent, legitimately classified into 4 groups (based on phylogeny) and 14 subgroups (based on the ≥ 60% of protein sequence identity). Species composition of AKR subgroups highlights their distinct emergence during plant evolution. Loss of AKR subgroups among plants was apparent and that various lineage-, order/family- and species-specific losses were observed. The subgroups IA, IVB and IVF were flourished and diversified well during plant evolution, likely related to the complexity of plant’s specialized metabolism and environmental adaptation. About 65% of AKRs were in genomic synteny regions across the plant kingdom and the AKRs relevant to important functions (e.g. vitamin B6 metabolism) were in profoundly conserved angiosperm-wide synteny communities. This study underscores the evolutionary landscape of plant AKRs and provides a comprehensive resource to facilitate the functional characterization of them.