Molecular Phylogeny of Misodendraceae

VIDAL-RUSSELL, R.; NICKRENT, D. L.

South Bend, Indiana, EE.UU.

Congreso; Midwest Ecology and Evolution Conference; 2004

The mistletoe family Misodendraceae (Sandalwood order, Santalales) is a manogeneric family of eight species endemic to southern South America. These plants are dioecious perennials with racemose inflorescences that bear achenes with three persistent staminodes. Upon maturation, these structures are involved in wind dispersal of the fruits. All species are stem parasites of trees in the genus Nothofagus (Nothofagaceae). Misodendrum has been divided into subgenus Misodendrum (with sections Misodendrum and Heterophyllum) and Angelopogon (with sections Angelopogon, Archiphyllum and Telophyllumm). This classification was based mainly in the number of stamens, stem texture and the number of flowers per inflorescence. Molecular phylogenetic data indicate Misodendraceae is sister to another mistletoe family Loranthaceae, but to date no infrageneric phylogeny has been proposed. DNA was obtained from all species in the genus except the rare M. macrolepis. Nuclear ribosomal intenal transcriber spacer (ITS) sequences were obtained. 37 percent of sites were parsimony informative, but with the exception of M. quadriflorum with a highly divergent ITS-1, the sequences were readily alignable. The ITS-1 region was 1.5 times more variable than ITS-2 and almost double the 5.8S region. A branch and bounds search using maximum parsimony without gap coding was performed on the ITS sequences using three species of Loranthaceae as outgroups. One most parsimonious tree was found (1148 steps) that supported the monophyly of the genus. Subgenus Angelopogon is paraphyletic and contains a monophyletic clade equivalent to subgenus Misodendrum. A well-supported clade (M, brachystachyum and M. oblongifolium) corresponds to section Archiphyllum.