title: The wheat resistance gene Lr34 results in the constitutive induction of multiple defense pathways in transgenic barley.
abstract: The wheat gene Lr34 encodes an ABCG-type transporter which provides durable resistance against multiple pathogens. Lr34 is functional as a transgene in barley, but its mode of action has remained largely unknown both in wheat and barley. Here we studied gene expression in uninfected barley lines transgenic for Lr34. Genes from multiple defense pathways contributing to basal and inducible disease resistance were constitutively active in seedlings and mature leaves. In addition, the hormones jasmonic acid and salicylic acid were induced to high levels, and increased levels of lignin as well as hordatines were observed. These results demonstrate a strong, constitutive re-programming of metabolism by Lr34. The resistant Lr34 allele (Lr34res) encodes a protein that differs by two amino acid polymorphisms from the susceptible Lr34sus allele. The deletion of a single phenylalanine residue in Lr34sus was sufficient to induce the characteristic Lr34-based responses. Combination of Lr34res and Lr34sus in the same plant resulted in a reduction of Lr34res expression by 8- to 20-fold when the low-expressing Lr34res line BG8 was used as a parent. Crosses with the high-expressing Lr34res line BG9 resulted in an increase of Lr34sus expression by 13- to 16-fold in progenies that inherited both alleles. These results indicate an interaction of the two Lr34 alleles on the transcriptional level. Reduction of Lr34res expression in BG8 crosses reduced the negative pleiotropic effects of Lr34res on barley growth and vigor without compromising disease resistance, suggesting that transgenic combination of Lr34res and Lr34sus can result in agronomically useful resistance.
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Harsh
authors: H
authors: Chauhan
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Rainer
authors: R
authors: Boni
authors: Institute of Organic Chemistry, University of Zurich, Winterthurerstrasse 190, CH8057, Zurich, Switzerland.
authors: Rahel
authors: R
authors: Bucher
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Benjamin
authors: B
authors: Kuhn
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Gabriele
authors: G
authors: Buchmann
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Justine
authors: J
authors: Sucher
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Liselotte L
authors: LL
authors: Selter
authors: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D06466, Stadt Seeland, Gatersleben, Germany.
authors: Goetz
authors: G
authors: Hensel
authors: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D06466, Stadt Seeland, Gatersleben, Germany.
authors: Jochen
authors: J
authors: Kumlehn
authors: Institute of Organic Chemistry, University of Zurich, Winterthurerstrasse 190, CH8057, Zurich, Switzerland.
authors: Laurent
authors: L
authors: Bigler
authors: Neuchâtel Platform of Analytical Chemistry, Institut de Chimie, Université de Neuchâtel, Avenue de Bellevaux 51, 2000, Neuchâtel, Switzerland.
authors: Gaëtan
authors: G
authors: Glauser
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Thomas
authors: T
authors: Wicker
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Simon G
authors: SG
authors: Krattinger
authors: Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, CH8008, Zurich, Switzerland.
authors: Beat
authors: B
authors: Keller
mesh_terms: D060467:Disease Resistance / Q000235:genetics*; D001467:Hordeum / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*
chemical_list: D010940:Plant Proteins
keywords: Lr34; allele mining; durable resistance; molecular breeding; transcriptomics