title: Phytoalexin production elicited by exogenously applied jasmonic acid in rice leaves (Oryza sativa L.) is under the control of cytokinins and ascorbic acid.
abstract: Jasmonic acid (JA) has been shown to be a signaling compound which elicits the production of secondary metabolites including phytoalexins in plants. It has been shown that the phytoalexin production is elicited by exogenously applied JA in rice leaves. We now show that this phytoalexin production by exogenously applied JA is significantly counteracted by cytokinins, kinetin and zeatin. Kinetin and zeatin also inhibit the induction of naringenin-7-O-methyltransferase (a key enzyme in rice phytoalexin production) by JA. A natural free radical scavenger, ascorbic acid (AsA) shows both counteractive and enhancing effects on JA-inducible phytoalexin production, depending on its concentration. This effect of AsA suggests that active oxygen species (AOS) may play important roles in phytoalexin production by JA in rice leaves.
authors.affiliation: Laboratory of Phytochemical Ecology, School of Agriculture, Ibaraki University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tamogami
authors.forename: R
authors.initials: R
authors.lastname: Rakwal
authors.forename: O
authors.initials: O
authors.lastname: Kodama
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000890:Anti-Infective Agents; D001205:Ascorbic Acid / Q000494:pharmacology*; D003517:Cyclopentanes / Q000494:pharmacology*; D003583:Cytokinins / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D007701:Kinetin; D008780:Methyltransferases / Q000037:antagonists & inhibitors; D012275:Oryza / Q000378:metabolism*; D054883:Oxylipins; D010936:Plant Extracts / Q000096:biosynthesis*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000378:metabolism*; D012717:Sesquiterpenes; D013729:Terpenes; D015026:Zeatin / Q000494:pharmacology; D000094162:Phytoalexins
chemical_list: D000890:Anti-Infective Agents; D003517:Cyclopentanes; D003583:Cytokinins; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D054883:Oxylipins; D010936:Plant Extracts; D010937:Plant Growth Regulators; D012717:Sesquiterpenes; D013729:Terpenes; C011006:jasmonic acid; D015026:Zeatin; D008780:Methyltransferases; C099725:naringenin 7-O-methyltransferase; D000225:Adenine; D007701:Kinetin; D001205:Ascorbic Acid; D000094162:Phytoalexins