title: The HvNAC6 transcription factor: a positive regulator of penetration resistance in barley and Arabidopsis.
abstract: Pathogens induce the expression of many genes encoding plant transcription factors, though specific knowledge of the biological function of individual transcription factors remains scarce. NAC transcription factors are encoded in plants by a gene family with proposed functions in both abiotic and biotic stress adaptation, as well as in developmental processes. In this paper, we provide convincing evidence that a barley NAC transcription factor has a direct role in regulating basal defence. The gene transcript was isolated by differential display from barley leaves infected with the biotrophic powdery mildew fungus, Blumeria graminis f.sp. hordei (Bgh). The full-length cDNA clone was obtained using 5'-RACE and termed HvNAC6, due to its high similarity to the rice homologue, OsNAC6. Gene silencing of HvNAC6 during Bgh inoculation compromises penetration resistance in barley epidermal cells towards virulent Bgh. Complementing the effect of HvNAC6 gene silencing, transient overexpression of HvNAC6 increases the occurrence of penetration resistant cells towards Bgh attack. Quantitative RT-PCR shows the early and transient induction of HvNAC6 in barley epidermis upon Bgh infection. Additionally, our results show that the Arabidopsis HvNAC6 homologue ATAF1 is also induced by Bgh and the ataf1-1 mutant line shows decreased penetration resistance to this non-host pathogen. Collectively, these data suggest a conserved role of HvNAC6 and ATAF1 in the regulation of penetration resistance in monocots and dicots, respectively.
authors.affiliation: Department of Plant Biology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Denmark. mkrj@life.ku.dk
authors.forename: Michael Krogh
authors.initials: MK
authors.lastname: Jensen
authors.forename: Jesper Henrik
authors.initials: JH
authors.lastname: Rung
authors.forename: Per Langkjaer
authors.initials: PL
authors.lastname: Gregersen
authors.forename: Torben
authors.initials: T
authors.lastname: Gjetting
authors.forename: Anja Thoe
authors.initials: AT
authors.lastname: Fuglsang
authors.forename: Michael
authors.initials: M
authors.lastname: Hansen
authors.forename: Nina
authors.initials: N
authors.lastname: Joehnk
authors.forename: Michael Foged
authors.initials: MF
authors.lastname: Lyngkjaer
authors.forename: David B
authors.initials: DB
authors.lastname: Collinge
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001203:Ascomycota / Q000502:physiology; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D001467:Hordeum / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics; D019441:Plant Epidermis / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis; D034622:RNA Interference; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013997:Time Factors; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000235:genetics
chemical_list: C517610:ATAF1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018076:DNA, Complementary; D010940:Plant Proteins; D012097:Repressor Proteins; D014157:Transcription Factors