Chloroplast DNA Phylogeny of the Papilionoid Legume Tribe Phaseoleae

Restriction map variation has been assayed in the slowly evolving chloroplast DNA (cpDNA) inverted repeat regions of 43 genera of the large and economically important legume tribe Phaseoleae and representatives of several allied tribes. Cladistic analyses of these data indicate that several plastome groups correspond well to subtribes recognized largely on the basis of morphological variation. Based on these cpDNA data, the tribe as a whole does not appear to be monophyletic, a result in accordance with current, morphologically-based hypotheses. Plastomes of several genera belonging to subtribes considered basal within Phaseoleae have as their sister groups plastomes of non-Phaseoleae tribes, notably Millettieae, the tribe considered to represent the ancestral stock from which diverse elements of Phaseoleae were derived. More unexpectedly, plastomes of the tribe Desmodieae fall within the clade that includes the most derived chloroplast genomes of Phaseoleae.