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Last results on floral architecture

> Contact: Domenica MANICACCI ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it Cette adresse email est protégée contre les robots des spammeurs, vous devez activer Javascript pour la voir. )
Catherine Damerval,  Agnès Rousselet, Hélène Corti

 

1. Evolution of floral traits and development

  • We used the phylogenies available in Ranunculales and Asterids to reconstruct the evolution of several architectural traits of the flower (eg, number of stamens, presence of nectar spurs ...) as related to the symmetry of the perianth. In both taxa, bilateral symmetry appears in a context where the number of floral parts is fixed. A greater diversity of evolutionary strategies appears in Ranunculales as compared with Asterids, suggesting a stronger canalization of development in the latter [Jabbour et al 2008]. Within Ranunculales, bilateral symmetry has evolved independently in Papaveraceae and Ranunculaceae, following scenarios different from what is described in the core Eudicots. In both cases it appears late in development. In Ranunculaceae, bilateral symmetry evolved from an ancestral type where floral organs are spirally inserted, it concerns both the calyx and the corolla, and it is associated with the presence of nectar spurs [Jabbour et al 2009]. In Papaveraceae, bilateral symmetry evolved from ancestral disymmetric type with whorled organs, and takes place along the transverse axis of the floral bud through asymmetric growth of stamen filaments and nectar spurs.

2. Evolution of developmental genes

  • The family of TCP transcription factors, initially defined from TB1, Cycloidea (CYC) and PCF genes, is involved in the control of growth processes in plants. The CYC gene is the key gene for floral symmetry in the model species Antirrhinum majus. We searched for homologs of this gene in Papaveraceae species with different floral symmetry, and identified two paralogous lineages (PapaCyL1 and 2) that derive from a duplication predating the divergence of the two major subfamilies, the Papaveroideae and the Fumarioideae (Damerval et al. 2007). Functional approaches (semiquantitative PCR, in situ hybridization) have shown that PapaCyL genes are expressed during flower development, in a pattern that appears correlated with the type of symmetry in the Fumarioideae species studied [Damerval et al. 2007]. The same type of analyses is underway in other families of basal Eudicots where bilateral symmetry arose independently, in an attempt to examine the diversity of evolutionary scenarios at the molecular level in addition to the developmental analyses.

 

> Collaborators GQE– Le Moulon : équipe Ge2MorF
Catherine Damerval, Yves Deveaux, Natalia Conde e Silva

> External collaborateurs
Patrick Laufs IJPB, Versailles ; Etienne Delanoy et Marie-Laure Martin Magniette, IPS2, Orsay ; Khawla  Seddiki, IDEEV.

> Where are they now ?

Beatriz GONÇALVES, Postdoctorante Doctorante (2010-2013)
Soizic HUPERT Stagiaire M1 SdV
Mathilde LATRON Stagiaire M2 EBE
Odrade NOUGUE, Doctorante Stagiaire M2 (2011)

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