Expansion of specialized metabolism-related superfamily genes via whole genome duplications during angiosperm evolution

Abstract

Specialized metabolism in land plants produces the diverse array of compounds, which is important in interaction with the environments. Generally, specialized metabolism-related genes consist of large gene families (superfamily), including cytochrome P450 monooxygenases (CYPs), 2-oxoglutarate-dependent dioxygenases (DOXs), and family-1 UDP-sugar dependent glycosyltransferases (UGTs), especially in angiosperms and gymnosperms. We investigated the changes in the numbers of these superfamily genes during the evolution of angiosperms by inferring gain and loss events in ancestral lineages of 5 angiosperms and 1 lycophyte. We observed the clear difference in the changes in the gene number among ancestral lineages. Intriguingly, gene gain events were coordinately occurred among CYP, DOX and UGT in lineage-specific manner, and the gain events were in good accordance with ancient whole genome duplication (WGD) events. Thus, the WGD events in angiosperms would have an important role in the expansion and evolution of specialized metabolism by providing prerequisite genetic resources for subsequent lineage-specific local tandem duplication (LTD) of superfamily genes as well as functional differentiation of these superfamily genes.