title: MADS-box genes from perennial ryegrass differentially expressed during transition from vegetative to reproductive growth.
abstract: In contrast to well-studied dicot plants like Arabidopsis and Antirrhinum, relatively few genes controlling the transition to flowering and flower development of agronomically important monocot species have been identified. In perennial ryegrass (Lolium perenne) the transition from vegetative to reproductive growth is triggered by an obligate vernalization period (primary induction) of at least 12 weeks at temperatures below 5 degrees C under short days, followed by increased temperature and day length (secondary induction). Here we report the isolation of nine ryegrass MADS-box (LpMADS) genes by a differential display method specific to this family of transcription factors. Three of the nine MADS-box genes show homology to the APETALA 1 (AP1) subfamily, two to the SEPALLATA (SEP) subfamily, one to the AGAMOUS-LIKE 6 (AGL6) subfamily, and three show homology to the newly identified OsMADS1 subfamily. The three AP1 homologues are up-regulated, both in the shoot apex and in leaves, in response to vernalization, while expression of the other six are increased by secondary induction during inflorescence development, although not in leaves. Differences in the sequence and hierarchy of flowering gene expression patterns indicate that the Arabidopsis-based flowering model is not completely applicable to explain the molecular events leading to the floral transition in grasses.
authors.affiliation: Plant Research Department, Risoe National Laboratory, P.O. Box 49, DK-4000 Roskilde, Denmark. klaus.petersen@risoe.dk
authors.forename: Klaus
authors.initials: K
authors.lastname: Petersen
authors.forename: Thomas
authors.initials: T
authors.lastname: Didion
authors.forename: Claus H
authors.initials: CH
authors.lastname: Andersen
authors.forename: Klaus K
authors.initials: KK
authors.lastname: Nielsen
mesh_terms: D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008129:Lolium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012098:Reproduction / Q000235:genetics / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D018076:DNA, Complementary; D026161:MADS Domain Proteins; D010940:Plant Proteins