BAX INHIBITOR-1 is required for full susceptibility of barley to powdery mildew.
BAX INHIBITOR-1 (BI-1) is one of the few proteins known to have cross-kingdom conserved functions in negative control of programmed cell death. Additionally, barley BI-1 (HvBI-1) suppresses defense responses and basal resistance to the powdery mildew fungus Blumeria graminis f. sp. hordei and enhances resistance to cell death-provoking fungi when overexpressed in barley. Downregulation of HvBI-1 by transient-induced gene silencing or virus-induced gene silencing limited susceptibility to B. graminis f. sp. hordei, suggesting that HvBI-1 is a susceptibility factor toward powdery mildew. Transient silencing of BI-1 did not limit supersusceptibility induced by overexpression of MLO. Transgenic barley plants harboring an HvBI-1 RNA interference (RNAi) construct displayed lower levels of HvBI-1 transcripts and were less susceptible to powdery mildew than wild-type plants. At the cellular level, HvBI-1 RNAi plants had enhanced resistance to penetration by B. graminis f. sp. hordei. These data support a function of BI-1 in modulating cell-wall-associated defense and in establishing full compatibility of B. graminis f. sp. hordei with barley.
Eichmann
Ruth
R
Lehrstuhl für Phytopathologie, Technische Universität München, Emil-Ramann-Strasse 2, D-85350 Freising-Weihenstephan, Germany. r.eichmann@lrz.tum.de
Bischof
Melanie
M
Weis
Corina
C
Shaw
Jane
J
Lacomme
Christophe
C
Schweizer
Patrick
P
Duchkov
Dimitar
D
Hensel
Götz
G
Kumlehn
Jochen
J
Hückelhoven
Ralph
R
D017209:Apoptosis; D001203:Ascomycota / Q000502:physiology*; D017353:Gene Deletion; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D020022:Genetic Predisposition to Disease; D001467:Hordeum / Q000235:genetics* / Q000378:metabolism* / Q000382:microbiology; D009154:Mutation; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified
D010940:Plant Proteins