title: The CRABS CLAW ortholog from California poppy (Eschscholzia californica, Papaveraceae), EcCRC, is involved in floral meristem termination, gynoecium differentiation and ovule initiation.
abstract: The Arabidopsis transcription factor CRABS CLAW (CRC) is a major determinant of carpel growth and fusion, and, in concert with other redundantly acting genes, of floral meristem termination. Its rice ortholog, however, has additional functions in specifying carpel organ identity. We were interested in understanding the history of gene function modulation of CRC-like genes during angiosperm evolution. Here, we report the identification and functional characterization of EcCRC, the Californica poppy (Eschscholzia californica) CRC ortholog. The downregulation of EcCRC by virus-induced gene silencing (VIGS) produces additional organ whorls that develop exclusively into gynoecia, resulting in a reiteration of the fourth whorl. Additionally, defects in carpel polarity and ovule initiation are apparent, and the observed phenotype is restricted to the gynoecium. Our results further show that the history of CRC-like genes during angiosperm evolution is characterized by gains of function, independent of duplication processes in this gene subfamily. Moreover, our data indicate that the ancestral angiosperm CRC-like gene was involved in floral meristem termination and the promotion of abaxial cell fate in the gynoecium, and that in the lineage leading to Arabidopsis, additional genes have been recruited to adopt some of these functions, resulting in a high degree of redundancy.
authors.affiliation: Department of Biology and Chemistry, University of Bremen, Germany.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Orashakova
authors.forename: Matthias
authors.initials: M
authors.lastname: Lange
authors.forename: Sabrina
authors.initials: S
authors.lastname: Lange
authors.forename: Stefanie
authors.initials: S
authors.lastname: Wege
authors.forename: Annette
authors.initials: A
authors.lastname: Becker
mesh_terms: D029681:Arabidopsis Proteins; D003001:Cloning, Molecular; D031675:Eschscholzia / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D035264:Flowers / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C119755:CRC protein, Arabidopsis; D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors