title: Role of camalexin, indole glucosinolates, and side chain modification of glucosinolate-derived isothiocyanates in defense of Arabidopsis against Sclerotinia sclerotiorum.
abstract: Plant secondary metabolites are known to facilitate interactions with a variety of beneficial and detrimental organisms, yet the contribution of specific metabolites to interactions with fungal pathogens is poorly understood. Here we show that, with respect to aliphatic glucosinolate-derived isothiocyanates, toxicity against the pathogenic ascomycete Sclerotinia sclerotiorum depends on side chain structure. Genes associated with the formation of the secondary metabolites camalexin and glucosinolate were induced in Arabidopsis thaliana leaves challenged with the necrotrophic pathogen S. sclerotiorum. Unlike S. sclerotiorum, the closely related ascomycete Botrytis cinerea was not identified to induce genes associated with aliphatic glucosinolate biosynthesis in pathogen-challenged leaves. Mutant plant lines deficient in camalexin, indole, or aliphatic glucosinolate biosynthesis were hypersusceptible to S. sclerotiorum, among them the myb28 mutant, which has a regulatory defect resulting in decreased production of long-chained aliphatic glucosinolates. The antimicrobial activity of aliphatic glucosinolate-derived isothiocyanates was dependent on side chain elongation and modification, with 8-methylsulfinyloctyl isothiocyanate being most toxic to S. sclerotiorum. This information is important for microbial associations with cruciferous host plants and for metabolic engineering of pathogen defenses in cruciferous plants that produce short-chained aliphatic glucosinolates.
authors.affiliation: RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan. henrik.stotz@uni-wuerzburg.de
authors.forename: Henrik U
authors.initials: HU
authors.lastname: Stotz
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sawada
authors.forename: Yukihisa
authors.initials: Y
authors.lastname: Shimada
authors.forename: Masami Y
authors.initials: MY
authors.lastname: Hirai
authors.forename: Eriko
authors.initials: E
authors.lastname: Sasaki
authors.forename: Markus
authors.initials: M
authors.lastname: Krischke
authors.forename: Paul D
authors.initials: PD
authors.lastname: Brown
authors.forename: Kazuki
authors.initials: K
authors.lastname: Saito
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kamiya
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001203:Ascomycota / Q000502:physiology*; D020171:Botrytis / Q000502:physiology; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D005961:Glucosinolates / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D051548:Histone Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D007211:Indoles / Q000378:metabolism*; D017879:Isothiocyanates / Q000378:metabolism*; D009154:Mutation; D057865:Plant Immunity; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome; D000094162:Phytoalexins; D000099224:p300-CBP-Associated Factor
chemical_list: D029681:Arabidopsis Proteins; D003577:Cytochrome P-450 Enzyme System; D005961:Glucosinolates; D051548:Histone Acetyltransferases; D007211:Indoles; D017879:Isothiocyanates; D012333:RNA, Messenger; D018749:RNA, Plant; D013844:Thiazoles; D014157:Transcription Factors; C102405:camalexin; D000094162:Phytoalexins; C530432:cytochrome P-450 79B2 protein, Arabidopsis; C530433:cytochrome P-450 79B3, Arabidopsis; C417307:PAD3 protein, Arabidopsis; C474636:GCN5 protein, Arabidopsis; D000099224:p300-CBP-Associated Factor