title: A homeodomain leucine zipper gene from Craterostigma plantagineum regulates abscisic acid responsive gene expression and physiological responses.
abstract: A subset of homeodomain leucine zipper proteins (HDZip) play a role in regulating adaptation responses including developmental adjustment to environmental cues in plants. Here we report the structural and functional characterisation of a dehydration responsive nuclear-targeted HDZip transcriptional regulator, CpHB-7. DNA-protein interaction studies suggest that CDeT6-19, a known ABA and dehydration responsive dehydrin gene, is a potential target gene of CpHB-7 in the desiccation-tolerant plant Craterostigma plantagineum. Transgenic plants that ectopically express CpHB-7 display reduced sensitivity towards ABA during seed germination and stomatal closure. Expression analysis reveals that genes with induced or repressed expression in CpHB-7 ectopic expression lines are either mostly repressed or induced by ABA, drought or salt treatment respectively, thus demonstrating that CpHB-7 modifies ABA-responsive gene expression as a negative regulator. CpHB-7 gene expression is also linked to early organ development, leading to the suggestion that CpHB-7 is functionally similar to the Arabidopsis transcription factor, ATHB-6.
authors.affiliation: Max-Planck-Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, Cologne D-50829, Germany.
authors.forename: Xin
authors.initials: X
authors.lastname: Deng
authors.forename: Jonathan
authors.initials: J
authors.lastname: Phillips
authors.forename: Anne
authors.initials: A
authors.lastname: Bräutigam
authors.forename: Peter
authors.initials: P
authors.lastname: Engström
authors.forename: Henrik
authors.initials: H
authors.lastname: Johannesson
authors.forename: Pieter B F
authors.initials: PB
authors.lastname: Ouwerkerk
authors.forename: Ida
authors.initials: I
authors.lastname: Ruberti
authors.forename: Julio
authors.initials: J
authors.lastname: Salinas
authors.forename: Pablo
authors.initials: P
authors.lastname: Vera
authors.forename: Rina
authors.initials: R
authors.lastname: Iannacone
authors.forename: Annemarie H
authors.initials: AH
authors.lastname: Meijer
authors.forename: Dorothea
authors.initials: D
authors.lastname: Bartels
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000502:physiology; D032181:Craterostigma / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000032:analysis; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000032:analysis; D012639:Seeds / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment; D014157:Transcription Factors / Q000737:chemistry / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; C122165:AtHB6 protein, Arabidopsis; D018398:Homeodomain Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C070556:dehydrin proteins, plant; D049452:Green Fluorescent Proteins; D000040:Abscisic Acid