RESUMO
Citrus sinensis and Citrus limonia were obtained by germination from seeds, and isotopic-labeling experiments using d-[1-13C]glucose were performed with the seedlings. After 60 days, the seedlings were analyzed by high-performance liquid chromatography-ultraviolet-solid-phase extraction-nuclear magnetic resonance, data and the 13C enrichment patterns of xanthyletin and seselin indicated that the pyran ring was formed by the methylerythritol phosphate pathway and that the coumarin moiety was derived from the shikimate pathway in both compounds. This information regarding the biosynthetic pathway can be used to increase resistance against phytopathogens, because xanthyletin and seselin are reported to have antimicrobial activity on the growth of Xylella fastidiosa, which causes citrus variegated chlorosis in orange.
Assuntos
Marcação por Isótopo/métodos , Piranocumarinas/metabolismo , Isótopos de Carbono , Cromatografia Líquida de Alta Pressão , Citrus/metabolismo , Citrus sinensis/metabolismo , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Doenças das Plantas/microbiologia , Piranocumarinas/química , Piranocumarinas/isolamento & purificação , Ácido Chiquímico/metabolismo , Extração em Fase Sólida , Espectrofotometria Ultravioleta , Xylella/efeitos dos fármacosRESUMO
Biosynthetic investigation of quinonemethide triterpenoid 22ß-hydroxy-maytenin (2) from in vitro root cultures of Peritassa laevigata (Celastraceae) was conducted using (13)C-precursor. The mevalonate pathway in P. laevigata is responsible for the synthesis of the quinonemethide triterpenoid scaffold. Moreover, anatomical analysis of P. laevigata roots cultured in vitro and in situ showed the presence of 22ß-hydroxy-maytenin (2) and maytenin (1) in the tissues from transverse or longitudinal sections with an intense orange color. MALDI-MS imaging confirmed the distribution of (2) and (1) in the more distal portions of the root cap, the outer cell layers, and near the vascular cylinder of P. laevigata in vitro roots suggesting a role in plant defense against infection by microorganisms as well as in the root exudation processes.
Assuntos
Antioxidantes/metabolismo , Magnoliaceae , Exsudatos de Plantas/metabolismo , Raízes de Plantas/metabolismo , Espermidina/análogos & derivados , Antioxidantes/química , Células Cultivadas , Técnicas In Vitro , Indolquinonas/química , Redes e Vias Metabólicas , Ácido Mevalônico/metabolismo , Exsudatos de Plantas/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espermidina/química , Espermidina/metabolismo , Triterpenos/químicaRESUMO
The biosynthetic route for epoxyangelate esters of the sesquiterpene lactones (STL) uvedalin and enhydrin from in vitro cultures of Smallanthus sonchifolius (Asteraceae) was investigated with (13)C-precursors for the first time in the literature. Photomicroscope analyses and studies using MALDI-MS imaging confirmed that glandular trichomes accumulate STL.
