title: Barley plants over-expressing the NAC transcription factor gene HvNAC005 show stunting and delay in development combined with early senescence.
abstract: The plant-specific NAC transcription factors have attracted particular attention because of their involvement in stress responses, senescence, and nutrient remobilization. The HvNAC005 gene of barley encodes a protein belonging to subgroup NAC-a6 of the NAC family. This study shows that HvNAC005 is associated with developmental senescence. It was significantly up-regulated following ABA treatment, supported by ABA-responsive elements in its promoter, but it was not up-regulated during dark-induced senescence. The C-termini of proteins closely related to HvNAC005 showed overall high divergence but also contained conserved short motifs. A serine- and leucine-containing central motif was essential for transcriptional activity of the HvNAC005 C-terminus in yeast. Over-expression of HvNAC005 in barley resulted in a strong phenotype with delayed development combined with precocious senescence. The over-expressing plants showed up-regulation of genes involved with secondary metabolism, hormone metabolism, stress, signalling, development, and transport. Up-regulation of senescence markers and hormone metabolism and signalling genes supports a role of HvNAC005 in the cross field of different hormone and signalling pathways. Binding of HvNAC005 to promoter sequences of putative target genes containing the T[G/A]CGT core motif was shown by direct protein-DNA interactions of HvNAC005 with promoters for two of the up-regulated genes. In conclusion, HvNAC005 was shown to be a strong positive regulator of senescence and so is an obvious target for the fine-tuning of gene expression in future attempts to improve nutrient remobilization related to the senescence process in barley.
authors.affiliation: Department of Genetics and Biotechnology, Aarhus University, Forsøgsvej 1, Slagelse DK-4200, Denmark.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Christiansen
authors.affiliation: Department of Genetics and Biotechnology, Aarhus University, Forsøgsvej 1, Slagelse DK-4200, Denmark.
authors.forename: Colette
authors.initials: C
authors.lastname: Matthewman
authors.affiliation: Department of Genetics and Biotechnology, Aarhus University, Forsøgsvej 1, Slagelse DK-4200, Denmark.
authors.forename: Dagmara
authors.initials: D
authors.lastname: Podzimska-Sroka
authors.affiliation: Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-Copenhagen N, Denmark.
authors.forename: Charlotte
authors.initials: C
authors.lastname: O'Shea
authors.affiliation: Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-Copenhagen N, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Lindemose
authors.affiliation: Department of Cellular and Molecular Medicin, University of Copenhagen, Blegdamsvej 3B, DK-Copenhagen N, Denmark.
authors.forename: Niels Erik
authors.initials: NE
authors.lastname: Møllegaard
authors.affiliation: Department of Genetics and Biotechnology, Aarhus University, Forsøgsvej 1, Slagelse DK-4200, Denmark.
authors.forename: Inger B
authors.initials: IB
authors.lastname: Holme
authors.affiliation: Department of Genetics and Biotechnology, Aarhus University, Forsøgsvej 1, Slagelse DK-4200, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Hebelstrup
authors.affiliation: Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-Copenhagen N, Denmark.
authors.forename: Karen
authors.initials: K
authors.lastname: Skriver
authors.affiliation: Department of Genetics and Biotechnology, Aarhus University, Forsøgsvej 1, Slagelse DK-4200, Denmark per.gregersen@mbg.au.dk.
authors.forename: Per L
authors.initials: PL
authors.lastname: Gregersen
mesh_terms: D000375:Aging / Q000502:physiology; D003001:Cloning, Molecular; D024202:Electrophoretic Mobility Shift Assay; D001467:Hordeum / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D010940:Plant Proteins / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified; D060888:Real-Time Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D059467:Transcriptome
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors
keywords: Barley; Hordeum vulgare L.; NAC transcription factors; gene regulation; senescence; senescence-associated genes; transgenic plants.