Phylogenetic analysis of 25 plant species representing 19 angiosperm families and one gymnosperm family based on 390 orthologous genes

High-throughput sequencing is fundamentally altering traditional phylogenetic classifications. While the Angiosperm Phylogeny Group (APG) III system based on chloroplast sequences has opened up a new era of angiosperm molecular classification, the use of nuclear genome sequences is more helpful for a precise phylogenetic analysis. However, such attempts have so far been applied to only a very limited number of angiosperm plant families. We constructed a phylogenetic tree of 25 plant species with well assembled genome sequences representing 19 angiosperm families and one gymnosperm family (as out group) using 390 orthologous genes. Our results strongly support the moving of Rhamnaceae to order Rosales from Rhamnales, abolishing Rhamnales, and establishing the new order Malpighiales in the APG III system. Our data also showed some characteristics inconsistent with the APG III classification and provided a reinterpretation of phylogeny for some of the families involved. We propose that Malpighiales should be placed in Malvids, not Fabids. The four monocot species representing four families were clustered together, indicating that monocot is a natural taxon. In summary, our results support almost all the APGIII treatments of the orders involved in this study and provided some surprising reinterpretations at levels beyond order.