title: Enzymatic oxidation products of allelochemicals as a basis for resistance against insects: effects on the corn leafhopper Dalbulus maidis.
abstract: Oxidation products of com allelochemicals generated by peroxidases or tyrosinases were tested in 10% sucrose solutions for effects on the corn leafhopper Dalbulus maidis. Some reduction in feeding was noted with hydrogen peroxide (a cofactor for peroxidase). Significant reduction in feeding was noted with chlorogenic acid, ferulic acid, p-coumaric acid, and 6-methoxybenzoxazolinone (MBOA), but not rutin at 400 ppm in solution. Oxidation products of these compounds all caused significantly less feeding by the leafhoppers compared to the original compound. Oxidation products generated by peroxidase from ferulic acid and 6-methoxybenzoxazolinone caused significant mortality to the leafhoppers within 5 days. Thus, provided conditions are such that oxidizing enzymes and allelochemicals can interact due to damage by insects, resistance may be significantly enhanced by the oxidized products as opposed to the effects of the allelochemicals alone.
authors.affiliation: Mycotoxin Research Unit, U.S.D.A., Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, Illinois 61604, USA.
authors.forename: P F
authors.initials: PF
authors.lastname: Dowd
authors.forename: F E
authors.initials: FE
authors.lastname: Vega
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001583:Benzoxazoles / Q000378:metabolism / Q000633:toxicity; D016009:Chi-Square Distribution; D002726:Chlorogenic Acid / Q000378:metabolism / Q000633:toxicity; D003373:Coumaric Acids / Q000378:metabolism / Q000633:toxicity; D005247:Feeding Behavior / Q000187:drug effects; D016166:Free Radical Scavengers / Q000378:metabolism / Q000633:toxicity*; D006430:Hemiptera / Q000187:drug effects* / Q000502:physiology; D014442:Monophenol Monooxygenase / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000737:chemistry / Q000378:metabolism; D010946:Plants, Medicinal / Q000378:metabolism*; D011422:Propionates; D012996:Solutions; D013395:Sucrose / Q000737:chemistry; D003313:Zea mays
chemical_list: D001583:Benzoxazoles; D003373:Coumaric Acids; D016166:Free Radical Scavengers; D011422:Propionates; D012996:Solutions; D002726:Chlorogenic Acid; C031896:6-methoxybenzoxazolinone; D013395:Sucrose; C004999:ferulic acid; D010544:Peroxidases; D014442:Monophenol Monooxygenase; C495469:p-coumaric acid