title: The role of BoFLC2 in cauliflower (Brassica oleracea var. botrytis L.) reproductive development.
abstract: In agricultural species that are sexually propagated or whose marketable organ is a reproductive structure, management of the flowering process is critical. Inflorescence development in cauliflower is particularly complex, presenting unique challenges for those seeking to predict and manage flowering time. In this study, an integrated physiological and molecular approach was used to clarify the environmental control of cauliflower reproductive development at the molecular level. A functional allele of BoFLC2 was identified for the first time in an annual brassica, along with an allele disrupted by a frameshift mutation (boflc2). In a segregating F₂ population derived from a cross between late-flowering (BoFLC2) and early-flowering (boflc2) lines, this gene behaved in a dosage-dependent manner and accounted for up to 65% of flowering time variation. Transcription of BoFLC genes was reduced by vernalization, with the floral integrator BoFT responding inversely. Overall expression of BoFT was significantly higher in early-flowering boflc2 lines, supporting the idea that BoFLC2 plays a key role in maintaining the vegetative state. A homologue of Arabidopsis VIN3 was isolated for the first time in a brassica crop species and was up-regulated by two days of vernalization, in contrast to findings in Arabidopsis where prolonged exposure to cold was required to elicit up-regulation. The correlations observed between gene expression and flowering time in controlled-environment experiments were validated with gene expression analyses of cauliflowers grown outdoors under 'natural' vernalizing conditions, indicating potential for transcript levels of flowering genes to form the basis of predictive assays for curd initiation and flowering time.
authors.affiliation: School of Plant Science, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia Stephen.Ridge@utas.edu.au.
authors.forename: Stephen
authors.initials: S
authors.lastname: Ridge
authors.affiliation: School of Medical and Applied Sciences, CQUniversity, Bundaberg Campus, Locked Bag 3333, Queensland 4670, Australia; and Queensland Government Department of Agriculture, Fisheries and Forestry, Bundaberg Research Station, Ashfield Road, Kalkie, Queensland 4670, Australia.
authors.forename: Philip H
authors.initials: PH
authors.lastname: Brown
authors.affiliation: School of Plant Science, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia.
authors.forename: Valérie
authors.initials: V
authors.lastname: Hecht
authors.affiliation: Rijk Zwaan Breeding B.V. De Lier, 2678 ZG, The Netherlands.
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Driessen
authors.affiliation: School of Plant Science, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia.
authors.forename: James L
authors.initials: JL
authors.lastname: Weller
mesh_terms: D001937:Brassica / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D026161:MADS Domain Proteins; D010940:Plant Proteins
keywords: BoFLC; BoFT; BoVIN3; Brassica oleracea; cauliflower; expression; flowering time; vernalization.