title: Evolutionary Co-Option of Floral Meristem Identity Genes for Patterning of the Flower-Like Asteraceae Inflorescence.
abstract: The evolutionary success of Asteraceae, the largest family of flowering plants, has been attributed to the unique inflorescence architecture of the family, which superficially resembles an individual flower. Here, we show that Asteraceae inflorescences (flower heads, or capitula) resemble solitary flowers not only morphologically but also at the molecular level. By conducting functional analyses for orthologs of the flower meristem identity genes LEAFY (LFY) and UNUSUAL FLORAL ORGANS (UFO) in Gerbera hybrida, we show that GhUFO is the master regulator of flower meristem identity, while GhLFY has evolved a novel, homeotic function during the evolution of head-like inflorescences. Resembling LFY expression in a single flower meristem, uniform expression of GhLFY in the inflorescence meristem defines the capitulum as a determinate structure that can assume floral fate upon ectopic GhUFO expression. We also show that GhLFY uniquely regulates the ontogeny of outer, expanded ray flowers but not inner, compact disc flowers, indicating that the distinction of different flower types in Asteraceae is connected with their independent evolutionary origins from separate branching systems.
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland (Y.Z., T.Z., S.K.B., S.T., K.M., T.H.T., P.E.); andDepartment of Biological Sciences, University at Buffalo, Buffalo, New York 14260 (V.A.A.).
authors.forename: Yafei
authors.identifier: 0000-0003-1243-8950
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland (Y.Z., T.Z., S.K.B., S.T., K.M., T.H.T., P.E.); andDepartment of Biological Sciences, University at Buffalo, Buffalo, New York 14260 (V.A.A.).
authors.forename: Teng
authors.identifier: 0000-0002-5189-3289
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland (Y.Z., T.Z., S.K.B., S.T., K.M., T.H.T., P.E.); andDepartment of Biological Sciences, University at Buffalo, Buffalo, New York 14260 (V.A.A.).
authors.forename: Suvi K
authors.initials: SK
authors.lastname: Broholm
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland (Y.Z., T.Z., S.K.B., S.T., K.M., T.H.T., P.E.); andDepartment of Biological Sciences, University at Buffalo, Buffalo, New York 14260 (V.A.A.).
authors.forename: Sari
authors.initials: S
authors.lastname: Tähtiharju
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland (Y.Z., T.Z., S.K.B., S.T., K.M., T.H.T., P.E.); andDepartment of Biological Sciences, University at Buffalo, Buffalo, New York 14260 (V.A.A.).
authors.forename: Katriina
authors.identifier: 0000-0003-3023-4978
authors.initials: K
authors.lastname: Mouhu
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland (Y.Z., T.Z., S.K.B., S.T., K.M., T.H.T., P.E.); andDepartment of Biological Sciences, University at Buffalo, Buffalo, New York 14260 (V.A.A.).
authors.forename: Victor A
authors.identifier: 0000-0002-0262-862X
authors.initials: VA
authors.lastname: Albert
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland (Y.Z., T.Z., S.K.B., S.T., K.M., T.H.T., P.E.); andDepartment of Biological Sciences, University at Buffalo, Buffalo, New York 14260 (V.A.A.).
authors.forename: Teemu H
authors.identifier: 0000-0002-3812-7213
authors.initials: TH
authors.lastname: Teeri
authors.affiliation: Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, Helsinki 00014, Finland (Y.Z., T.Z., S.K.B., S.T., K.M., T.H.T., P.E.); andDepartment of Biological Sciences, University at Buffalo, Buffalo, New York 14260 (V.A.A.) paula.elomaa@helsinki.fi.
authors.forename: Paula
authors.identifier: 0000-0001-6512-0810
authors.initials: P
authors.lastname: Elomaa
mesh_terms: D019659:Asteraceae / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D019143:Evolution, Molecular; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D017403:In Situ Hybridization; D056626:Inflorescence / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D018519:Meristem / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011485:Protein Binding; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020798:Two-Hybrid System Techniques
chemical_list: D010940:Plant Proteins