title: A peroxidase gene expressed during early developmental stages of the parasitic plant Orobanche ramosa.
abstract: Broomrapes (Orobanche spp.) are holoparasitic weeds that cause devastating losses in many economically important crops. The molecular mechanisms that control the early stages of host infection in Orobanche are poorly understood. In the present study, the role of peroxidase has been examined during pre-infection growth and development of O. ramosa, using an in vitro model system. Peroxidase activity was histochemically localized at the tips of actively growing radicles and nascent attachment organs. Addition of exogenous catalase resulted in a significant reduction in the apical growth rate of the radicle. The prx1 gene encoding a putative class III peroxidase was cloned from a cDNA library of O. ramosa and was found to be expressed specifically during the early stages of the parasitic life cycle. The exogenous addition of sucrose resulted in significantly reduced prx1 transcript levels and in a dramatic change in radicle development from polarized apical growth to isotropic growth and the formation of tubercle-like structures. The results indicate an important role of peroxidases during the early parasitic stages of Orobanche.
authors.affiliation: Departamento de Genética, Universidad de Córdoba, Campus de Rabanales C5, E-14071 Córdoba, Spain. clara2gonzalez@yahoo.com
authors.forename: Clara Isabel
authors.initials: CI
authors.lastname: González-Verdejo
authors.forename: Xabier
authors.initials: X
authors.lastname: Barandiaran
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Moreno
authors.forename: José Ignacio
authors.initials: JI
authors.lastname: Cubero
authors.forename: Antonio
authors.initials: A
authors.lastname: Di Pietro
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D015870:Gene Expression; D015723:Gene Library; D018525:Germination; D006651:Histocytochemistry; D006861:Hydrogen Peroxide / Q000378:metabolism; D008969:Molecular Sequence Data; D031672:Orobanche / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D009195:Peroxidase / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013395:Sucrose / Q000494:pharmacology
chemical_list: D017382:Reactive Oxygen Species; D013395:Sucrose; D006861:Hydrogen Peroxide; D009195:Peroxidase