Floral MADS box genes and homeotic gender dimorphism in Thalictrum dioicum (Ranunculaceae) - a new model for the study of dioecy.
In most dioecious angiosperm species, flowers are initially perfect but abort either stamens or carpels during their development, indicating that sex determination occurs after floral organ identity has been established. Dioecious members of the genus Thalictrum (meadow-rue), however, produce flowers that lack aborted organs. Examination of early flower development of T. dioicum confirms that flowers are male or female from inception, raising the possibility that genetic mechanisms working at or above the level of organ identity promote sex determination through a homeotic-like mechanism. In order to investigate this possibility, we identified homologs of the organ identity genes PISTILLATA (PI), APETALA3 (AP3) and AGAMOUS (AG) from T. dioicum and the hermaphroditic species T. thalictroides. A combination of early and late duplication events was uncovered in these gene lineages and expression analyses indicate that these events are generally associated with divergence in gene regulation. In light of these findings, we discuss the potential of T. dioicum as a new model for the study of sex determination in the basal eudicots.
Di Stilio
Verónica S
VS
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA. distilio@u.washington.edu
Kramer
Elena M
EM
Baum
David A
DA
D000595:Amino Acid Sequence; D035264:Flowers / Q000235:genetics* / Q000648:ultrastructure; D026161:MADS Domain Proteins / Q000235:genetics*; D008855:Microscopy, Electron, Scanning; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D029626:Ranunculaceae / Q000145:classification / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D026161:MADS Domain Proteins; D010940:Plant Proteins