title: Tight regulation of plant immune responses by combining promoter and suicide exon elements.
abstract: Effector-triggered immunity (ETI) is activated when plant disease resistance (R) proteins recognize the presence of pathogen effector proteins delivered into host cells. The ETI response generally encompasses a defensive 'hypersensitive response' (HR) that involves programmed cell death at the site of pathogen recognition. While many R protein and effector protein pairs are known to trigger HR, other components of the ETI signaling pathway remain elusive. Effector genes regulated by inducible promoters cause background HR due to leaky protein expression, preventing the generation of relevant transgenic plant lines. By employing the HyP5SM suicide exon, we have developed a strategy to tightly regulate effector proteins such that HR is chemically inducible and non-leaky. This alternative splicing-based gene regulation system was shown to successfully control Bs2/AvrBs2-dependent and RPP1/ATR1Δ51-dependent HR in Nicotiana benthamiana and Nicotiana tabacum, respectively. It was also used to generate viable and healthy transgenic Arabidopsis thaliana plants that inducibly initiate HR. Beyond enabling studies on the ETI pathway, our regulatory strategy is generally applicable to reduce or eliminate undesired background expression of transgenes.
authors.affiliation: Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Tania L
authors.initials: TL
authors.lastname: Gonzalez
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis St, Emeryville, CA 94608, USA Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Bao N
authors.initials: BN
authors.lastname: Nguyen
authors.affiliation: Department of Plant & Microbial Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Staskawicz
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis St, Emeryville, CA 94608, USA Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Dominique
authors.initials: D
authors.lastname: Loqué
authors.affiliation: Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA Department of Chemistry, University of California, Berkeley, CA 94720, USA mingch@berkeley.edu.
authors.forename: Ming C
authors.initials: MC
authors.lastname: Hammond
mesh_terms: D017398:Alternative Splicing; D017360:Arabidopsis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology; D060467:Disease Resistance / Q000235:genetics*; D005091:Exons; D018506:Gene Expression Regulation, Plant; D009868:Oomycetes / Q000235:genetics; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000235:genetics; D011401:Promoter Regions, Genetic; D014026:Nicotiana / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: C417273:AvrBs2 protein, Xanthomonas campestris; D001426:Bacterial Proteins; D003907:Dexamethasone