Abstract Detail

After the book - Progress in parasitic plant research since Kuijt's Biology of Parasitic Flowering Plants (1969)

Blarer, Albert [1], Bänziger, Hans [2], Endress, Peter K. [1], Anderson, Frank [3], Nickrent, Daniel L. [4].

Rafflesiales – problems and advances in research.

The group of holoparasites that include the spectacular Rafflesia has been traditionally classified either as a single family (Rafflesiaceae s. lat.) composed of two subfamilies and four tribes or as an order (Rafflesiales) with four families (Rafflesiaceae s. str., Cytinaceae, Apodanthaceae, and Mitrastemonaceae). Moreover, Hydnoraceae and Rafflesiales have been suggested, via most traditional classifications, to be close relatives. In contrast, recent molecular phylogenetic analyses, using nuclear, mitochondrial, and chloroplast genes and thorough taxon sampling, show that Hydnoraceae are not related to the remaining Rafflesiales but are a component of Piperales. Analyses of nuclear SSU rDNA sequences placed a monophyletic Rafflesiales among the eudicots, specifically within Malvales. This result was compatible to previous work using mitochondrial genes wherein Cytinaceae was shown to be related to Malvales. In addition, Apodanthaceae shares a number of floral structural features with Malvales. In contrast, an association with Malvales was not seen in a recent molecular phylogenetic analysis using the mitochondrial gene matR where Rafflesia and Rhizanthes were shown to be a part of Malpighiales and Mitrastema was a component of Ericales. We have conducted extensive molecular phylogenetic analyses using nuclear and mitochondrial genes and, in contrast to previous work, have attained complete generic sampling within Rafflesiales. Our results indicate that mitochondrial gene trees are being influenced by horizontal gene transfer events, thus compromising their utility as phylogenetic markers.

1 - University of Zurich, Institute of Systematic Botany, Zurich, CH-8008, Switzerland
2 - Chiang Mai University, Department of Entomology, Faculty of Agriculture, Chiang Mai, 50200, Thailand
3 - Southern Illinois University, Department of Zoology, Carbondale, Illinois, 62901-6509, USA
4 - Southern Illinois University, Department of Plant Biology, 1125 Lincoln Drive, Carbondale, Illinois, 62901-6509, USA

Keywords:
parasitic plants
Rafflesiaceae
horizontal gene transfer
matR
phylogeny
nuclear genes
mitochondrial genes
chloroplast genes.

Presentation Type: Symposium
Session: 16-6
Location: Ballroom 2 (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 3:45 PM
Abstract ID:492