title: Salicylic acid production in response to biotic and abiotic stress depends on isochorismate in Nicotiana benthamiana.
abstract: Salicylic acid (SA) is an important signal involved in the activation of defence responses against abiotic and biotic stress. In tobacco, benzoic acid or glucosyl benzoate were proposed to be precursors of SA. This is in sharp contrast with studies in Arabidopsis thaliana, where SA derives from isochorismate. We have determined the importance of isochorismate for SA biosynthesis in Nicotiana benthamiana using virus-induced gene silencing of the isochorismate synthase (ICS) gene. Plants with silenced ICS expression do not accumulate SA after exposure to UV or to pathogen stress. Plants with silenced ICS expression also exhibit strongly decreased levels of phylloquinone, a product of isochorismate. Our data provide evidence for an isochorismate-derived synthesis of SA in N. benthamiana.
authors.affiliation: Department of Biology, University of Fribourg, Ch. du Musée 10, 1700 Fribourg, Switzerland.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Catinot
authors.forename: Antony
authors.initials: A
authors.lastname: Buchala
authors.forename: Eliane
authors.initials: E
authors.lastname: Abou-Mansour
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Métraux
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002827:Chorismic Acid / Q000378:metabolism*; D053138:Cyclohexenes / Q000378:metabolism*; D017931:DNA Primers; D019751:Intramolecular Transferases / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D020156:Salicylic Acid / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000201:enzymology / Q000378:metabolism*
chemical_list: D053138:Cyclohexenes; D017931:DNA Primers; C052985:isochorismic acid; D019751:Intramolecular Transferases; C058486:isochorismate synthase; D002827:Chorismic Acid; D020156:Salicylic Acid