title: Early genes responsive to abscisic acid during heterophyllous induction in Marsilea quadrifolia.
abstract: The aquatic fern Marsilea quadrifolia produces different types of leaves in response to changes in natural environment and culture conditions. When the conditions are in favor of producing the submerged-type leaves, exogenous application of the plant hormone abscisic acid (ABA) induces the formation of aerial-type leaves. Tissues responsive to ABA were localized to the shoot apical meristem and the associated organ primordia. From these tissues, at least two tiers of ABA-regulated early genes were identified, including seven primary genes and seventeen secondary genes. These genes, designated ABRH for ABA-responsive heterophylly, showed diverse expression patterns during the course of heterophyllous induction. Changes in the transcript level of ABRH genes started early, within 0.5-1.0 h after the addition of ABA to the culture medium. Some changes were transient while the others were persistent. The ABRHs contain extensive sequence homology to known genes, including those encoding transcription factors, protein kinases, membrane transporters, metabolic enzymes, structural proteins and those encoded by the chloroplast genome. Identification of these ABRHs is a first step toward the understanding of the regulation mechanisms of heterophylly, and the results suggest the involvement of novel metabolic and regulatory pathways in ABA-controlled morphogenesis.
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: T C
authors.initials: TC
authors.lastname: Hsu
authors.forename: H C
authors.initials: HC
authors.lastname: Liu
authors.forename: J S
authors.initials: JS
authors.lastname: Wang
authors.forename: R W
authors.initials: RW
authors.lastname: Chen
authors.forename: Y C
authors.initials: YC
authors.lastname: Wang
authors.forename: B L
authors.initials: BL
authors.lastname: Lin
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000235:genetics; D003001:Cloning, Molecular; D018742:DNA, Chloroplast / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000648:ultrastructure; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics
chemical_list: D018742:DNA, Chloroplast; D018076:DNA, Complementary; D008565:Membrane Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D000040:Abscisic Acid