title: The synergistic activation of FLOWERING LOCUS C by FRIGIDA and a new flowering gene AERIAL ROSETTE 1 underlies a novel morphology in Arabidopsis.
abstract: The genetic changes underlying the diversification of plant forms represent a key question in understanding plant macroevolution. To understand the mechanisms leading to novel plant morphologies we investigated the Sy-0 ecotype of Arabidopsis that forms an enlarged basal rosette of leaves, develops aerial rosettes in the axils of cauline leaves, and exhibits inflorescence and floral reversion. Here we show that this heterochronic shift in reproductive development of all shoot meristems requires interaction between dominant alleles at AERIAL ROSETTE 1 (ART1), FRIGIDA (FRI), and FLOWERING LOCUS C (FLC) loci. ART1 is a new flowering gene that maps 14 cM proximal to FLC on chromosome V. ART1 activates FLC expression through a novel flowering pathway that is independent of FRI and independent of the autonomous and vernalization pathways. Synergistic activation of the floral repressor FLC by ART1 and FRI is required for delayed onset of reproductive development of all shoot meristems, leading to the Sy-0 phenotype. These results demonstrate that modulation in flowering-time genes is one of the mechanisms leading to morphological novelties.
authors.affiliation: Department of Plant Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada.
authors.forename: Branislava
authors.initials: B
authors.lastname: Poduska
authors.forename: Tania
authors.initials: T
authors.lastname: Humphrey
authors.forename: Antje
authors.initials: A
authors.lastname: Redweik
authors.forename: Vojislava
authors.initials: V
authors.lastname: Grbić
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C418902:At5g10140 protein, Arabidopsis; C414613:FRI protein, Arabidopsis; D026161:MADS Domain Proteins