Phylogenomic analysis of Ranunculales resolves branching events across the order

Abstract

Poppies (Papaver), columbines (Aquilegia), buttercups (Ranunculus) and related species, are members of the order Ranunculales, the sister lineage to all other eudicots. Using coalescent and concatenated methods to analyse alignments of 882 putatively single copy genes, we have developed a robust phylogenetic tree including 27 species representing all major lineages of Ranunculales and most tribes of Papaveraceae. This first phylogenomic analysis including examples of Ranunculales, asterids, caryophillids and rosids provides the necessary foundation for future investigations of character evolution in Ranunculales. For example, the production of benzylisoquinoline alkaloids with known and potential pharmaceutical applications is largely restricted to Ranunculales. Understanding species relationships in the order is critical for understanding the evolution of benzylisoquinoline alkaloid biosynthesis across Ranunculales, including the production of morphine and codeine in opium poppy (Papaver somniferum). Analysis of gene tree discordance in selected portions of the phylogenetic tree suggests that the few observed differences between trees derived from supermatrix and coalescent-based summary analyses are attributable to incomplete lineage sorting. Discordance between gene tree and species tree inferences should be taken into account in future comparative analyses of character evolution in Ranunculales.