Transcriptional regulation by an NAC (NAM-ATAF1,2-CUC2) transcription factor attenuates ABA signalling for efficient basal defence towards Blumeria graminis f. sp. hordei in Arabidopsis.
ATAF1 is a member of a largely uncharacterized plant-specific gene family encoding NAC transcription factors, and is induced in response to various abiotic and biotic stimuli in Arabidopsis thaliana. Previously, we showed that a mutant allele of ATAF1 compromises penetration resistance in Arabidopsis with respect to the non-host biotrophic pathogen Blumeria graminis f. sp. hordei (Bgh). In this study, we have used genome-wide transcript profiling to characterize signalling perturbations in ataf1 plants following Bgh inoculation. Comparative transcriptomic analyses identified an over-representation of abscisic acid (ABA)-responsive genes, including the ABA biosynthesis gene AAO3, which is significantly induced in ataf1 plants compared to wild-type plants following inoculation with Bgh. Additionally, we show that Bgh inoculation results in decreased endogenous ABA levels in an ATAF1-dependent manner, and that the ABA biosynthetic mutant aao3 showed increased penetration resistance to Bgh compared to wild-type plants. Furthermore, we show that ataf1 plants show ABA-hyposensitive phenotypes during seedling development and germination. Our data support a negative correlation between ABA levels and penetration resistance, and identify ATAF1 as a new stimuli-dependent attenuator of ABA signalling for the mediation of efficient penetration resistance in Arabidopsis upon Bgh attack.
Jensen
Michael K
MK
Department of Plant Biology, Faculty of Life Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
Hagedorn
Peter H
PH
de Torres-Zabala
Marta
M
Grant
Murray R
MR
Rung
Jesper H
JH
Collinge
David B
DB
Lyngkjaer
Michael F
MF
D000040:Abscisic Acid / Q000378:metabolism*; D042931:Aldehyde Oxidase / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001203:Ascomycota / Q000472:pathogenicity*; D016000:Cluster Analysis; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D054046:Plant Stomata / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
C517610:ATAF1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018749:RNA, Plant; D012097:Repressor Proteins; D014157:Transcription Factors; D000040:Abscisic Acid; C470342:AAO3 protein, Arabidopsis; D042931:Aldehyde Oxidase