title: The promoter of the cereal VERNALIZATION1 gene is sufficient for transcriptional induction by prolonged cold.
abstract: The VERNALIZATION1 (VRN1) gene of temperate cereals is transcriptionally activated by prolonged cold during winter (vernalization) to promote flowering. To investigate the mechanisms controlling induction of VRN1 by prolonged cold, different regions of the VRN1 gene were fused to the GREEN FLUORESCENT PROTEIN (GFP) reporter and expression of the resulting gene constructs was assayed in transgenic barley (Hordeum vulgare). A 2 kb segment of the promoter of VRN1 was sufficient for GFP expression in the leaves and shoot apex of transgenic barley plants. Fluorescence increased at the shoot apex prior to inflorescence initiation and was subsequently maintained in the developing inflorescence. The promoter was also sufficient for low-temperature induction of GFP expression. A naturally occurring insertion in the proximal promoter, which is associated with elevated VRN1 expression and early flowering in some spring wheats, did not abolish induction of VRN1 transcription by prolonged cold, however. A translational fusion of the promoter and transcribed regions of VRN1 to GFP, VRN1::GFP, was localised to nuclei of cells at the shoot apex of transgenic barley plants. The distribution of VRN1::GFP at the shoot apex was similar to the expression pattern of the VRN1 promoter-GFP reporter gene. Fluorescence from the VRN1::GFP fusion protein increased in the developing leaves after prolonged cold treatment. These observations suggest that the promoter of VRN1 is targeted by mechanisms that trigger vernalization-induced flowering in economically important temperate cereal crops.
authors.affiliation: Division of Plant Industry, The Commonwealth Scientific and Industrial Research Organisation, Canberra, Australian Capital Territory, Australia.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Alonso-Peral
authors.forename: Sandra N
authors.initials: SN
authors.lastname: Oliver
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Casao
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Greenup
authors.forename: Ben
authors.initials: B
authors.lastname: Trevaskis
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D000595:Amino Acid Sequence; D003080:Cold Temperature; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D017930:Genes, Reporter / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000378:metabolism; D001467:Hordeum / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics; D059372:Nucleotide Motifs / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D018515:Plant Leaves / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D018520:Plant Shoots / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics*; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012639:Seeds / Q000235:genetics*; D014158:Transcription, Genetic; D014908:Triticum / Q000235:genetics
chemical_list: D020121:5' Untranslated Regions; D010940:Plant Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins