Evolutionary developmental genetics of floral monosymmetry in Cleome violacea (Cleomaceae)

Abstract

Cleomaceae is an ideal system in which to investigate evolutionary transitions between monosymmetric flowers from polysymmetric ancestors. Previous studies have not produced a resolved phylogeny or explored the role of the candidate gene, TCP1, in the evolution of monosymmetric flowers. Here, I use phylogenetic analysis of chloroplast genes matK, ndhF, and ycf1, in addition to the mitochondrial gene rps3 and nuclear ribosomal gene ITS1, to generate the first support for relationships that constitute the backbone of the phylogeny. I then explore TCP1 homologues in Cleomaceae by isolating two paralogues from three species (Cleome spinosa, C. violacea, and C. viridiflora) and correlating expression domain of one copy, ClevioTCP1.1, in C. violacea to floral development using in situ hybridization and scanning electron microscopy. These results provide a phylogenetic framework in which to interpret patterns of evolution and are the first steps towards understanding floral symmetry evolution at the molecular level in Cleomaceae.