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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Abscisic Acid / pharmacology
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Amino Acid Sequence
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Arabidopsis Proteins / chemistry
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Arabidopsis Proteins / physiology
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Craterostigma* / genetics
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Gene Expression Profiling
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Gene Expression Regulation, Plant*
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Germination / drug effects
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Green Fluorescent Proteins / analysis
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Homeodomain Proteins / chemistry
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Homeodomain Proteins / genetics
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Homeodomain Proteins / metabolism*
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Homeodomain Proteins / physiology
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Leucine Zippers
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Molecular Sequence Data
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Plant Leaves / drug effects
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Plant Leaves / growth & development
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Plant Leaves / metabolism
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Plant Proteins / chemistry
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Plant Proteins / genetics
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Plant Proteins / metabolism*
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Plants, Genetically Modified / drug effects
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Plants, Genetically Modified / growth & development
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Plants, Genetically Modified / metabolism
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Recombinant Fusion Proteins / analysis
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Seeds / drug effects
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Seeds / growth & development
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Seeds / metabolism
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Sequence Alignment
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Transcription Factors / chemistry
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Transcription Factors / physiology
Substances
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Arabidopsis Proteins
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AtHB6 protein, Arabidopsis
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Homeodomain Proteins
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Plant Proteins
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Recombinant Fusion Proteins
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Transcription Factors
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dehydrin proteins, plant
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Green Fluorescent Proteins
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Abscisic Acid