title: A single-electron reducing quinone oxidoreductase is necessary to induce haustorium development in the root parasitic plant Triphysaria.
abstract: Parasitic plants in the Orobanchaceae develop haustoria in response to contact with host roots or chemical haustoria-inducing factors. Experiments in this manuscript test the hypothesis that quinolic-inducing factors activate haustorium development via a signal mechanism initiated by redox cycling between quinone and hydroquinone states. Two cDNAs were previously isolated from roots of the parasitic plant Triphysaria versicolor that encode distinct quinone oxidoreductases. QR1 encodes a single-electron reducing NADPH quinone oxidoreductase similar to zeta-crystallin. The QR2 enzyme catalyzes two electron reductions typical of xenobiotic detoxification. QR1 and QR2 transcripts are upregulated in a primary response to chemical-inducing factors, but only QR1 was upregulated in response to host roots. RNA interference technology was used to reduce QR1 and QR2 transcripts in Triphysaria roots that were evaluated for their ability to form haustoria. There was a significant decrease in haustorium development in roots silenced for QR1 but not in roots silenced for QR2. The infrequent QR1 transgenic roots that did develop haustoria had levels of QR1 similar to those of nontransgenic roots. These experiments implicate QR1 as one of the earliest genes on the haustorium signal transduction pathway, encoding a quinone oxidoreductase necessary for the redox bioactivation of haustorial inducing factors.
authors.affiliation: Department of Crop Science, Faculty of Agriculture, University of Peradeniya, Peradeniya, Sri Lanka 20400.
authors.forename: Pradeepa C G
authors.initials: PC
authors.lastname: Bandaranayake
authors.forename: Tatiana
authors.initials: T
authors.lastname: Filappova
authors.forename: Alexey
authors.initials: A
authors.lastname: Tomilov
authors.forename: Natalya B
authors.initials: NB
authors.lastname: Tomilova
authors.forename: Denneal
authors.initials: D
authors.lastname: Jamison-McClung
authors.forename: Quy
authors.initials: Q
authors.lastname: Ngo
authors.forename: Kentaro
authors.initials: K
authors.lastname: Inoue
authors.forename: John I
authors.initials: JI
authors.lastname: Yoder
mesh_terms: D018076:DNA, Complementary / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006790:Host-Parasite Interactions; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics / Q000378:metabolism*; D031670:Orobanchaceae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000469:parasitology*; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics; D015398:Signal Transduction
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D018749:RNA, Plant; D016660:NAD(P)H Dehydrogenase (Quinone)