title: Ectopic accumulation of linalool confers resistance to Xanthomonas citri subsp. citri in transgenic sweet orange plants.
abstract: In order to clarify whether high linalool content in citrus leaves alone induces strong field resistance to citrus canker caused by Xanthomonas citri subsp. citri (Xcc), and to assess whether this trait can be transferred to a citrus type highly sensitive to the bacterium, transgenic 'Hamlin' sweet orange (Citrus sinensis L. Osbeck) plants over-expressing a linalool synthase gene (CuSTS3-1) were generated. Transgenic lines (LIL) with the highest linalool content showed strong resistance to citrus canker when spray inoculated with the bacterium. In LIL plants inoculated by wounding (multiple-needle inoculation), the linalool level was correlated with the repression of the bacterial titer and up-regulation of defense-related genes. The exogenous application of salicylic acid, methyl jasmonate or linalool triggered responses similar to those constitutively induced in LIL plants. The linalool content in Ponkan mandarin leaves was significantly higher than that of leaves from six other representative citrus genotypes with different susceptibilities to Xcc. We propose that linalool-mediated resistance might be unique to citrus tissues accumulating large amounts of volatile organic compounds in oil cells. Linalool might act not only as a direct antibacterial agent, but also as a signal molecule involved in triggering a non-host resistance response against Xcc.
authors.affiliation: Institute of Fruit Tree and Tea Science (NIFTS), National Agriculture and Bio-Oriented Research Organization (NARO), Shizuoka 424-0292, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Shimada
authors.affiliation: Institute of Fruit Tree and Tea Science (NIFTS), National Agriculture and Bio-Oriented Research Organization (NARO), Shizuoka 424-0292, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Endo
authors.affiliation: Fundecitrus, Av. Dr. Adhemar de Barros Pereira, 201, 14807-040 Vila Melhado, Araraquara, Sao Paulo, Brazil.|Instituto de Biología Molecular y Celular de Plantas (IBMCP/CSIC-UPV), Ingeniero Fausto Elio, Valencia 46022, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Rodríguez
authors.affiliation: Institute of Fruit Tree and Tea Science (NIFTS), National Agriculture and Bio-Oriented Research Organization (NARO), Shizuoka 424-0292, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujii
authors.affiliation: Institute of Fruit Tree and Tea Science (NIFTS), National Agriculture and Bio-Oriented Research Organization (NARO), Shizuoka 424-0292, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Goto
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.
authors.forename: Takakazu
authors.initials: T
authors.lastname: Matsuura
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Hojo
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Ikeda
authors.affiliation: Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki 710-0046, Japan.
authors.forename: Izumi C
authors.initials: IC
authors.lastname: Mori
authors.affiliation: Institute of Fruit Tree and Tea Science (NIFTS), National Agriculture and Bio-Oriented Research Organization (NARO), Shizuoka 424-0292, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujikawa
authors.affiliation: Fundecitrus, Av. Dr. Adhemar de Barros Pereira, 201, 14807-040 Vila Melhado, Araraquara, Sao Paulo, Brazil.|Instituto de Biología Molecular y Celular de Plantas (IBMCP/CSIC-UPV), Ingeniero Fausto Elio, Valencia 46022, Spain.
authors.forename: Leandro
authors.initials: L
authors.lastname: Peña
authors.affiliation: Faculty of Agriculture, Shizuoka University, Shizuoka 422-8529, Japan.
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Omura
mesh_terms: D000080462:Acyclic Monoterpenes; D002957:Citrus / Q000235:genetics* / Q000382:microbiology; D060467:Disease Resistance / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006836:Hydro-Lyases / Q000235:genetics; D039821:Monoterpenes / Q000032:analysis*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000382:microbiology; D014974:Xanthomonas / Q000472:pathogenicity*
chemical_list: D000080462:Acyclic Monoterpenes; D039821:Monoterpenes; C018584:linalool; D006836:Hydro-Lyases; C092055:S-linalool synthase
keywords: canker; citrus; non-host resistance; systematic acquired resistance