Phylogenetic Relationships in the Papilionoideae (Family Leguminosae) Based on Nucleotide Sequences of cpDNA (rbcL) and ncDNA (ITS 1 and 2)

Abstract

Sequences of cpDNA (rbcL) were determined for 94 species and of ncDNA [ITS 1+2 regions (internal transcribed spacer) of rDNA] for 75 species representing mainly the papilionoid tribes Sophoreae, Thermopsideae, Podalyrieae, Liparieae, Crotalarieae, and Genisteae. Sequence data were used to reconstruct the underlying molecular phylogeny. Several clusters and furcations were identical in therbcL and ITS trees of the Papilionoideae, indicating that a reticulate evolution due to past hybridization of members from different tribes and genera is unlikely: The Sophoreae (especiallyStyphnolobium japonicum(syn.Sophora japonica) andSophora secundiflora) are positioned at the base of the papilionoid tree, whereas some otherSophoraspecies (Sophora davidii, flavescens, jaubertii, microphylla) are closely related to Thermopsideae/Podalyrieae. The Thermopsideae/Podylyrieae cluster (including Liparieae) shares ancestry with the Crotalarieae and Genisteae.Argyrolobium(African taxa) andMelolobiumcluster between Crotalarieae and Genisteae. In the Genisteae three clusters are apparent: the monophyletic genusLupinus,theCytisus-,and theGenista-group. According to this analysis, theCytisus-complex includesCytisus, Lembotropis, Chamaecytisus, Spartocytisus,andCalicotome.TheGenista-group consists ofGenista, Teline,andChamaespartium sagittale.Other genera (e.g.,Adenocarpus, Argyrocytisus, Cytisophyllum, Erinacea, Laburnum, Petteria, Retama, Spartium,andUlex) could not be attributed unequivocally to theCytisusorGenistacomplex.