title: Ryecyanatines A and B and ryecarbonitrilines A and B, substituted cyanatophenol, cyanatobenzo[1,3]dioxole, and benzo[1,3]dioxolecarbonitriles from rye (Secale cereale L.) root exudates: Novel metabolites with allelopathic activity on Orobanche seed germination and radicle growth.
abstract: Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which represent serious weed problems causing heavy yield losses on important crops. Current control relies on the use of certain agronomic practices, resistant crop varieties, and herbicides, albeit success has been marginal. Agronomic practices such as the use of allelopathic species in intercropping or cover crops, or the use of direct seedling over residues of allelopathic species incorporate the principle of allelopathy exerted by molecules exuded from roots or released by crop residues to control broomrapes. In addition, the isolation of natural substances from root exudates of plants with potential to inhibit broomrape development opens the door to the design of new herbicides based on natural and benign sources. Ryecyanatines A and B and ryecarbonitrilines A and B, the first new substituted cyanatophenol, substituted cyanatobenzo[1,3]dioxole, and the latter two new substituted benzo[1,3]dioxolecarbonitriles were isolated from rye (Secale cereale L.) root exudates. They were characterized as 4-cyanato-2-methoxyphenol, 2-cyanato-benzo[1,3]dioxole, 2-methoxybenzo[1,3]dioxole-5-carbonitrile and benzo[1,3]dioxole-2-carbonitrile by spectroscopic (essentially NMR and HRESI MS spectra) methods. These compounds were investigated for allelopathic activity on Orobanche germination and development. Ryecarbonitriline A induced germination of Orobanche cumana seeds, and this germination can be considered as suicidal because O. cumana does not parasite rye roots and cannot survive without host resources beyond germination stage. In addition, ryecyanatine A promotes a rapid cessation of O. cumana, Orobanche crenata and Orobanche minor radicle growth with the promotion of a layer of papillae at the radicle tip in O. cumana and O. crenata hampering the contact of the parasite to the host. Ryecarbonitriline B also displayed the same activity although being less active than ryecyanatine A and mainly restricted to O. cumana.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, 4, 80126 Napoli, Italy.
authors.forename: Alessio
authors.initials: A
authors.lastname: Cimmino
authors.affiliation: Utsunomiya University, Weed Science Center, Utsunomiya, Tochigi 321-8505, Japan; INRA, UMR1347 Agroécologie, BP 86510, F-21000 Dijon, France.
authors.forename: Mónica
authors.initials: M
authors.lastname: Fernández-Aparicio
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, 4, 80126 Napoli, Italy.
authors.forename: Fabiana
authors.initials: F
authors.lastname: Avolio
authors.affiliation: Utsunomiya University, Weed Science Center, Utsunomiya, Tochigi 321-8505, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Yoneyama
authors.affiliation: Institute for Sustainable Agriculture, CSIC, Apdo. 4084, 14080 Córdoba, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: Rubiales
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, 4, 80126 Napoli, Italy. Electronic address: evidente@unina.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Evidente
mesh_terms: D064089:Allelopathy; D052117:Benzodioxoles / Q000737:chemistry* / Q000302:isolation & purification; D018525:Germination / Q000187:drug effects*; D006540:Herbicides / Q000737:chemistry / Q000302:isolation & purification; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry / Q000302:isolation & purification; D031672:Orobanche / Q000187:drug effects*; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification; D010675:Pheromones / Q000737:chemistry; D053147:Plant Exudates / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry; D057685:Plant Weeds / Q000187:drug effects; D012434:Secale / Q000737:chemistry*; D012639:Seeds / Q000254:growth & development
chemical_list: D052117:Benzodioxoles; D006540:Herbicides; D009570:Nitriles; D010636:Phenols; D010675:Pheromones; D053147:Plant Exudates; C000598220:ryecarbonitriline A; C000598221:ryecyanatine A
keywords: Orobanche; Parasitic weeds; Root exudates; Ryecarbonitrilines A and B; Ryecyanatines A and B; Secale cereale; Seed germination/inhibition