title: Reactive oxygen species, nitric oxide, and their interactions play different roles in Cupressus lusitanica cell death and phytoalexin biosynthesis.
abstract: Beta-thujaplicin Is a natural troponoid with strong antifungal, antiviral, and anticancer activities. Beta-thujaplicin production in yeast elicitor-treated Cupressus lusitanica cell culture and its relationships with reactive oxygen species (ROS) and nitric oxide (NO) production and hypersensitive cell death were investigated. Superoxide anion radical (O2*-) induced cell death and inhibited beta-thujaplicin accumulation, whereas hydrogen peroxide (H2O2) induced beta-thujaplicin accumulation but did not significantly affect cell death. Both elicitor and O2*- induced programmed cell death, which can be blocked by protease inhibitors, protein kinase inhibitors, and Ca2+ chelators. Elicitor-induced NO generation was nitric oxide synthase (NOS)-dependent. Inhibition of NO generation by NOS inhibitors and NO scavenger partly blocked the elicitor-induced beta-thujaplicin accumulation and cell death, and NO donors strongly induced cell death. Interaction among NO, H2O2, and O2*- shows that NO production and H2O2 production are interdependent, but NO and O2*- accumulation were negatively related because of coconsumption of NO and O2*-. NO- and O2*- -induced cell death required each other, and both were required for elicitor-induced cell death. A direct interaction between NO and O2*- was implicated in the production of a potent oxidant peroxynitrite, which might mediate the elicitor-induced cell death.
authors.affiliation: Laboratory of Forest Chemistry and Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.|Children's Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030 USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Laboratory of Forest Chemistry and Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Laboratory of Forest Chemistry and Biochemistry, Faculty of Agriculture, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Kokki
authors.initials: K
authors.lastname: Sakai
mesh_terms: D016923:Cell Death; D002478:Cells, Cultured; D029781:Cupressus / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D039821:Monoterpenes / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012717:Sesquiterpenes; D013729:Terpenes / Q000378:metabolism*; D013997:Time Factors; D014334:Tropolone / Q000031:analogs & derivatives / Q000378:metabolism; D000094162:Phytoalexins
chemical_list: D039821:Monoterpenes; D017382:Reactive Oxygen Species; D012717:Sesquiterpenes; D013729:Terpenes; D009569:Nitric Oxide; D014334:Tropolone; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase; C009479:beta-thujaplicin; D000094162:Phytoalexins