title: The MADS box gene, FOREVER YOUNG FLOWER, acts as a repressor controlling floral organ senescence and abscission in Arabidopsis.
abstract: The ectopic expression of a MADS box gene FOREVER YOUNG FLOWER (FYF) caused a significant delay of senescence and a deficiency of abscission in flowers of transgenic Arabidopsis. The defect in floral abscission was found to be due to a deficiency in the timing of cell separation of the abscission zone cells. Down-regulation of INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) may contribute to the delay of the floral abscission in 35S:FYF flowers. FYF was found to be highly expressed in young flowers prior to pollination and was significantly decreased after pollination, a pattern that correlated with its function. Ethylene insensitivity in senescence/abscission and the down-regulation of ETHYLENE RESPONSE DNA-BINDING FACTOR 1 (EDF1) and EDF2, downstream genes in the ethylene response, in 35S:FYF Arabidopsis suggested a role for FYF in regulating senescence/abscission by suppressing the ethylene response. This role was further supported by the fact that 35S:FYF enhanced the delay of flower senescence/abscission in ethylene response 1 (etr1), ethylene-insensitive 2 (ein2) and constitutive triple response 1 (ctr1) mutants, which have defects in upstream genes of the ethylene signaling pathway. The presence of a repressor domain in the C-terminus of FYF and the enhancement of the delay of senescence/abscission in FYF+SRDX (containing a suppression motif) transgenic plants suggested that FYF acts as a repressor. Indeed, in FYF-DR+VP16 transgenic dominant-negative mutant plants, in which FYF was converted to a potent activator by fusion to a VP16-AD motif, the senescence/abscission of the flower organs was significantly promoted, and the expression of BOP2, IDA and EDF1/2 was up-regulated. Our data suggest a role for FYF in controlling floral senescence/abscission by repressing ethylene responses and regulating the expression of BOP2 and IDA in Arabidopsis.
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan 40227, Taiwan.
authors.forename: Ming-Kun
authors.initials: MK
authors.lastname: Chen
authors.forename: Wei-Han
authors.initials: WH
authors.lastname: Hsu
authors.forename: Pei-Fang
authors.initials: PF
authors.lastname: Lee
authors.forename: Muthu
authors.initials: M
authors.lastname: Thiruvengadam
authors.forename: Hong-Ie
authors.initials: HI
authors.lastname: Chen
authors.forename: Chang-Hsien
authors.initials: CH
authors.lastname: Yang
mesh_terms: D017360:Arabidopsis / Q000033:anatomy & histology / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016922:Cellular Senescence; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation; D005030:Ethylenes / Q000494:pharmacology; D035264:Flowers / Q000033:anatomy & histology / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D016254:Mutagenesis, Insertional; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000033:anatomy & histology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C581420:AGL42 protein, Arabidopsis; D029681:Arabidopsis Proteins; C506721:BOP2 protein, Arabidopsis; D018076:DNA, Complementary; D005030:Ethylenes; C512213:IDA protein, Arabidopsis; D026161:MADS Domain Proteins; D010937:Plant Growth Regulators; D018749:RNA, Plant; D014157:Transcription Factors; C036216:ethylene