title: An activated form of UFO alters leaf development and produces ectopic floral and inflorescence meristems.
abstract: Plants are unique in their ability to continuously produce new meristems and organ primordia. In Arabidopsis, the transcription factor LEAFY (LFY) functions as a master regulator of a gene network that is important for floral meristem and organ specification. UNUSUAL FLORAL ORGANS (UFO) is a co-activator of LEAFY and is required for proper activation of APETALA3 in the floral meristem during the specification of stamens and petals. The ufo mutants display defects in other parts of the flower and the inflorescence, suggestive of additional roles. Here we show that the normal determinacy of the developing Arabidopsis leaves is affected by the expression of a gain-of-function UFO fusion protein with the VP16 transcriptional activator domain. In these lines, the rosette and cauline leaf primordia exhibit reiterated serration, and upon flowering produce ectopic meristems that develop into flowers, bract leaves and inflorescences. These striking phenotypes reveal that developing leaves maintain the competency to initiate flower and inflorescence programs. Furthermore, the gain-of-function phenotypes are dependent on LFY and the SEPALLATA (SEP) MADS-box transcription factors, indicative of their functional interactions with UFO. The findings of this study also suggest that UFO promotes the establishment of the lateral meristems and primordia in the peripheral zone of the apical and floral meristems by enhancing the activity of LFY. These novel phenotypes along with the mutant phenotypes of UFO orthologs in other plant species suggest a broader function for UFO in plants.
authors.affiliation: Plant Biotechnology Institute, National Research Council, Saskatoon, Canada.
authors.forename: Eddy
authors.initials: E
authors.lastname: Risseeuw
authors.affiliation: Plant Biotechnology Institute, National Research Council, Saskatoon, Canada.
authors.forename: Prakash
authors.initials: P
authors.lastname: Venglat
authors.affiliation: Plant Biotechnology Institute, National Research Council, Saskatoon, Canada.
authors.forename: Daoquan
authors.initials: D
authors.lastname: Xiang
authors.affiliation: Plant Biotechnology Institute, National Research Council, Saskatoon, Canada.
authors.forename: Kristina
authors.initials: K
authors.lastname: Komendant
authors.affiliation: Plant Biotechnology Institute, National Research Council, Saskatoon, Canada.
authors.forename: Tim
authors.initials: T
authors.lastname: Daskalchuk
authors.affiliation: Plant Biotechnology Institute, National Research Council, Saskatoon, Canada.
authors.forename: Vivijan
authors.initials: V
authors.lastname: Babic
authors.affiliation: Department of Biological Sciences, University of Windsor, Windsor, Canada.
authors.forename: William
authors.initials: W
authors.lastname: Crosby
authors.affiliation: Plant Biotechnology Institute, National Research Council, Saskatoon, Canada.
authors.forename: Raju
authors.initials: R
authors.lastname: Datla
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D056626:Inflorescence / Q000254:growth & development*; D018519:Meristem / Q000254:growth & development*; D010641:Phenotype; D018515:Plant Leaves / Q000254:growth & development*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; C074747:LFY protein, Arabidopsis; D014157:Transcription Factors; C098247:UFO protein, Arabidopsis