title: Accumulation of brachycerine, an antioxidant glucosidic indole alkaloid, is induced by abscisic acid, heavy metal, and osmotic stress in leaves of Psychotria brachyceras.
abstract: Psychotria brachyceras Muell. Arg. produces the antioxidant monoterpene indole alkaloid (MIA) brachycerine, which, besides retaining a glucose residue, has its terpenoid moiety derived not from secologanin, but probably from epiloganin, representing a new subclass of MIAs. In this work we showed that osmotic stress agents, such as sodium chloride, sorbitol and polyethylene glycol (PEG), induced brachycerine accumulation in leaf disks of P. brachyceras. Other oxidative stress inducers, such as exposure to aluminum and silver, also increased brachycerine content. Abscisic acid (ABA) treatment was shown to increase brachycerine yield, suggesting its involvement in brachycerine induction during osmotic stress. Ascorbate peroxidase activity was induced in PEG-treated leaf disks, whereas superoxide dismutase (SOD) activity remained unaltered. Assays with specific inhibitors of the cytosolic mevalonate (MVA) and plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathways showed that the terpenoid moiety of brachycerine derived predominantly from the MEP pathway. These results suggest a potential involvement of brachycerine in plant defense against osmotic/oxidative stress damage, possibly contributing to detoxification of hydroxyl radical and superoxide anion as a SOD-like molecule.
authors.affiliation: Graduate Program in Cell and Molecular Biology, Plant Physiology Laboratory, Center for Biotechnology, Federal University of Rio Grande do Sul (UFRGS), CP 15005, Porto Alegre RS 91501-970, Brazil. Electronic address: naila.cannes@gmail.com.
authors.forename: Naíla Cannes
authors.initials: NC
authors.lastname: do Nascimento
authors.forename: Paloma Koprovski
authors.initials: PK
authors.lastname: Menguer
authors.forename: Amélia Teresinha
authors.initials: AT
authors.lastname: Henriques
authors.forename: Arthur Germano
authors.initials: AG
authors.lastname: Fett-Neto
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000222:Adaptation, Physiological; D000975:Antioxidants / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism; D026121:Indole Alkaloids / Q000378:metabolism; D007211:Indoles / Q000378:metabolism*; D019216:Metals, Heavy / Q000009:adverse effects*; D039821:Monoterpenes / Q000378:metabolism*; D009997:Osmotic Pressure; D018384:Oxidative Stress; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D032069:Psychotria / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D005960:Glucosides; D026121:Indole Alkaloids; D007211:Indoles; D019216:Metals, Heavy; D039821:Monoterpenes; D010937:Plant Growth Regulators; C433964:brachycerine; D000040:Abscisic Acid
keywords: ABA; Antioxidant; Brachycerine; CAT; DW; DXR; GPX; HMGR; IPP; MEP; MEP pathway; MIA; MVA; NaCl; Osmotic stress; PEG; ROS; SOD; abscisic acid; catalase; cytosolic mevalonate; deoxyxylulose 5-phosphate reductoisomerase; dry weight; glutathione peroxidase; hydroxymethylglutaryl CoA reductase; isopentenyl diphosphate; monoterpene indole alkaloid; plastidic 2-C-methyl-d-erythritol 4-phosphate; polyethylene glycol; reactive oxygen species; sodium chloride; superoxide dismutase