title: Cabomba as a model for studies of early angiosperm evolution.
abstract: BACKGROUND
  The angiosperms, or flowering plants, diversified in the Cretaceous to dominate almost all terrestrial environments. Molecular phylogenetic studies indicate that the orders Amborellales, Nymphaeales and Austrobaileyales, collectively termed the ANA grade, diverged as separate lineages from a remaining angiosperm clade at a very early stage in flowering plant evolution. By comparing these early diverging lineages, it is possible to infer the possible morphology and ecology of the last common ancestor of the extant angiosperms, and this analysis can now be extended to try to deduce the developmental mechanisms that were present in early flowering plants. However, not all species in the ANA grade form convenient molecular-genetic models.
  
  
  METHODS
  The present study reviews the genus Cabomba (Nymphaeales), which shows a range of features that make it potentially useful as a genetic model. We focus on characters that have probably been conserved since the last common ancestor of the extant flowering plants. To facilitate the use of Cabomba as a molecular model, we describe methods for its cultivation to flowering in the laboratory, a novel Cabomba flower expressed sequence tag database, a well-adapted in situ hybridization protocol and a measurement of the nuclear genome size of C. caroliniana. We discuss the features required for species to become tractable models, and discuss the relative merits of Cabomba and other ANA-grade angiosperms in molecular-genetic studies aimed at understanding the origin of the flowering plants.
authors.affiliation: Laboratoire de Reproduction et Développement des Plantes, UMR 5667, CNRS-INRA-Université de Lyon, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France.
authors.forename: Aurelie C M
authors.initials: AC
authors.lastname: Vialette-Guiraud
authors.forename: Michael
authors.initials: M
authors.lastname: Alaux
authors.forename: Fabrice
authors.initials: F
authors.lastname: Legeai
authors.forename: Cedric
authors.initials: C
authors.lastname: Finet
authors.forename: Pierre
authors.initials: P
authors.lastname: Chambrier
authors.forename: Spencer C
authors.initials: SC
authors.lastname: Brown
authors.forename: Aurelie
authors.initials: A
authors.lastname: Chauvet
authors.forename: Carlos
authors.initials: C
authors.lastname: Magdalena
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Rudall
authors.forename: Charles P
authors.initials: CP
authors.lastname: Scutt
mesh_terms: D005075:Biological Evolution; D035264:Flowers / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D008954:Models, Biological; D030702:Nymphaeaceae / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D010802:Phylogeny