title: Control of Floret Symmetry by RAY3, SvDIV1B, and SvRAD in the Capitulum of Senecio vulgaris
abstract: All members of Asteraceae, the largest flowering family, have a unique compressed inflorescence known as a capitulum, which resembles a solitary flower. The capitulum often consists of bilateral (zygomorphic) ray florets and radial (actinomorphic) disc florets. In Antirrhinum majus, floral zygomorphy is established by the interplay between dorsal petal identity genes, CYCLOIDEA (CYC) and RADIALIS (RAD), and a ventral gene DIVARICATA (DIV). To investigate the role of CYC, RAD, and DIV in the development of ray and disc florets within a capitulum, we isolated homologs of these genes from an Asteraceae species, Senecio vulgaris (common groundsel). After initial uniform expression of RAY3 (CYC), SvRAD, and SvDIV1B in ray florets only, RAY3 and SvRAD were exclusively expressed in the ventral petals of the ray florets. Our functional analysis further showed that RAY3 promotes and SvDIV1B represses petal growth, confirming their roles in floral zygomorphy. Our results highlight that while floral symmetry genes such as RAY3 and SvDIV1B appear to have a conserved role in petal growth in both Senecio and Antirrhinum, the regulatory relationships and expression domains are divergent, allowing ventral petal elongation in Senecio versus dorsal petal elongation in Antirrhinum In S vulgaris, diversification of CYC genes has led to novel interactions; SvDIV1B inhibits RAY3 and SvRAD, and may activate RAY2 This highlights how recruitment of floral symmetry regulators into dynamic networks was crucial for creating a complex and elaborate structure such as the capitulum.
authors.affiliation: Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.
authors.forename: Helena Maria Pereira
authors.identifier: 0000-0002-3703-7531
authors.initials: HM
authors.lastname: Garcês
authors.affiliation: Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.
authors.forename: Victoria M R
authors.identifier: 0000-0002-9930-1377
authors.initials: VM
authors.lastname: Spencer
authors.affiliation: Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom minsung.kim@manchester.ac.uk.
authors.forename: Minsung
authors.identifier: 0000-0002-8470-793X
authors.initials: M
authors.lastname: Kim
mesh_terms: D032161:Antirrhinum / Q000235:genetics; D035264:Flowers / Q000033:anatomy & histology* / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D012674:Senecio / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*
chemical_list: D010940:Plant Proteins