title: Secretion of momilactone A from rice roots to the rhizosphere.
abstract: The secretion levels of momilactone A from rice (Oryza sativa L.) seedlings of eight cultivars into the rhizosphere were compared with the endogenous momilactone A concentrations in their shoots and roots. All rice cultivars contained momilactone A in the shoots and roots, and concentrations differed among the cultivars. Momilactone A was also found in all culture solutions in which the rice seedlings were grown, and the concentrations differed among the cultivars. The momilactone A concentrations in the culture solutions were reflected in the momilactone A concentrations in the shoots. These results suggest that all rice cultivars may produce momilactome A and secrete momilactone A into the culture solutions. The secretion levels of momilactone A may be more dependent on their capacities for momilactone A production in the shoots than on their capacities for momilactone A transportation from the shoots into the environment via the roots. As momilactone A acts as an antimicrobial and allelopathic agent, the secretion of momilactone A into the rice rhizosphere may provide a competitive advantage for root establishment through local suppression of soil microorganisms and inhibition of the growth of competing plant species.
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa 761-0795, Japan. hisashi@ag.kagawa-u.ac.jp
authors.forename: Hisashi
authors.initials: H
authors.lastname: Kato-Noguchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ino
authors.forename: Katsumi
authors.initials: K
authors.lastname: Ota
mesh_terms: D003470:Culture Media; D004224:Diterpenes / Q000378:metabolism* / Q000494:pharmacology; D018546:Hypocotyl / Q000187:drug effects / Q000254:growth & development; D012275:Oryza / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D012996:Solutions
chemical_list: D003470:Culture Media; D004224:Diterpenes; D012996:Solutions; C116023:momilactone A