title: Deregulation of Plant Cell Death Through Disruption of Chloroplast Functionality Affects Asexual Sporulation of Zymoseptoria tritici on Wheat.
abstract: Chloroplasts have a critical role in plant defense as sites for the biosynthesis of the signaling compounds salicylic acid (SA), jasmonic acid (JA), and nitric oxide (NO) and as major sites of reactive oxygen species production. Chloroplasts, therefore, regarded as important players in the induction and regulation of programmed cell death (PCD) in response to abiotic stresses and pathogen attack. The predominantly foliar pathogen of wheat Zymoseptoria tritici is proposed to exploit the plant PCD, which is associated with the transition in the fungus to the necrotrophic phase of infection. In this study virus-induced gene silencing was used to silence two key genes in carotenoid and chlorophyll biosynthesis, phytoene desaturase (PDS) and Mg-chelatase H subunit (ChlH). The chlorophyll-deficient, PDS- and ChlH-silenced leaves of susceptible plants underwent more rapid pathogen-induced PCD but were significantly less able to support the subsequent asexual sporulation of Z. tritici. Conversely, major gene (Stb6)-mediated resistance to Z. tritici was partially compromised in PDS- and ChlH-silenced leaves. Chlorophyll-deficient wheat ears also displayed increased Z. tritici disease lesion formation accompanied by increased asexual sporulation. These data highlight the importance of chloroplast functionality and its interaction with regulated plant cell death in mediating different genotype and tissue-specific interactions between Z. tritici and wheat.
authors.affiliation: 1Wheat Pathogenomics Team, Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, AL5 2JQ, U.K.;
authors.forename: Wing-Sham
authors.initials: WS
authors.lastname: Lee
authors.affiliation: 2Bioimaging, Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, AL5 2JQ, U.K.
authors.forename: B Jean
authors.initials: BJ
authors.lastname: Devonshire
authors.affiliation: 1Wheat Pathogenomics Team, Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, AL5 2JQ, U.K.;
authors.forename: Kim E
authors.initials: KE
authors.lastname: Hammond-Kosack
authors.affiliation: 1Wheat Pathogenomics Team, Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, AL5 2JQ, U.K.;
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Rudd
authors.affiliation: 1Wheat Pathogenomics Team, Plant Biology and Crop Science Department, Rothamsted Research, Harpenden, AL5 2JQ, U.K.;
authors.forename: Kostya
authors.initials: K
authors.lastname: Kanyuka
mesh_terms: D001203:Ascomycota / Q000502:physiology*; D016923:Cell Death; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D014908:Triticum / Q000382:microbiology* / Q000648:ultrastructure
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010940:Plant Proteins; D002734:Chlorophyll; C011006:jasmonic acid; D006861:Hydrogen Peroxide; D020156:Salicylic Acid