Submitted to: International Journal of Plant Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/26/2006
Publication Date: 6/20/2007
Citation: Borsch, T., Hilu, K.W., Wiersema, J.H., Lohne, C., Barthlott, W., Wilde, V. 2007. Phylogeny analysis of Nymphaea (Nymphaeaceae): Evidence from substitutions and microstructural changes in the chloroplast trnT-trnF region. International Journal of Plant Sciences. 168:639-671. Interpretive Summary: Water-lilies are among the most beautiful of aquatic plants, forming the centerpiece of most aquatic gardens. The current view of relationships in the water-lily genus, Nymphaea, is based mainly on their appearance. DNA base sequences were used to compare species of water-lilies and their close relatives. The results of this study identified three evolutionary lineages of water-lilies. One lineage is composed of plants that grow in temperate regions, the second lineage includes the tropical day-blooming plants, and a third group consists of tropical night-blooming plants. As a result of this research water-lily breeders can better predict which species are likely to successfully interbreed to produce new types of water-lilies. The study also addresses fundamental questions about the evolution of the earliest flowering plants.
Technical Abstract: Phylogenetic relationships of Nymphaea are presented based on an analysis of the chloroplast trnT-trnF region, from 35 of an estimated 45–50 species. Because Nymphaea is the most speciose, phenotypically most diverse, and the only genus of Nymphaeales with a nearly global distribution, rooting of trees was extended to more distant outgroups (Amborella, Austrobaileyales) to infer its status in Nymphaeales. The Australian genus Ondinea appeared nested within Nymphaea subg. Anecphya with high support. Monophyly of the Nymphaea-Ondinea clade is only weakly supported, with a Euryale-Victoria clade appearing as sister. The three major Nymphaea lineages constitute a north temperate subg. Nymphaea that is sister to the remaining species, a subgg. Hydrocallis-Lotos clade, and a subgg. Anecphya-Brachyceras-Ondinea clade. The pantropical subg. Brachyceras as currently circumscribed does not appear natural, with N. petersiana belonging to subg. Lotos. A hypothesis of its paraphyly to subg. Anecphya requires further testing. Frequent microstructural changes in the two spacers and the intron are highly informative, exhibiting even lower levels of homoplasy than substitutions. AT-rich, satellite-like sequence parts have evolved independently in the P8 loop of the trnL group I intron in Nuphar and in major lineages of Nymphaea. They seem to be conserved in sequence within but highly variable among species. Moreover, the trnT-trnF region provides signal that allows recognition (barcoding) of most species analysed so far.