title: UV-induced momilactone B accumulation in rice rhizosphere.
abstract: UV-irradiation increased the concentration of momilactone B in shoots and roots of rice seedlings, and increasing the irradiation increased the concentration. The concentration in 90-min UV-irradiated shoots and roots, respectively, was 31.8- and 3.6-fold higher than that in non-irradiated shoots and roots. After UV-irradiation the concentration of momilactone B in rice shoots decreased. There was, however, an accumulation of momilactone B in the medium in which UV-irradiated seedlings were grown. Five days after UV-irradiation, momilactone B in the medium was at a level 2.5 times greater than on day 0, which was 47% of momilactone B in the seedlings, suggesting that rice may actively secrete momilactone B into medium. Therefore, UV-irradiation increased not only production of momilactone B in rice seedlings but also secretion of momilactone B into rice rhizosphere. As momilactone B acts as an antimicrobial and allelopathic agent, secretion of momilactone B into the rhizosphere may provide a competitive advantage for root establishment through local suppression of soil microorganism 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: Hiroya
authors.initials: H
authors.lastname: Kujime
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ino
mesh_terms: D004224:Diterpenes / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D007783:Lactones / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism* / Q000528:radiation effects*; D018517:Plant Roots / Q000378:metabolism* / Q000528:radiation effects*; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D004224:Diterpenes; D007783:Lactones; C477203:momilactone B