Farnesol-2-14C was readily incorporated into ipomeamarone, one of the furanoterpenoids produced in sweet potato infected with the black rot fungus,Ceratocystis fumbriata. This was demonstrated by isolating labeled ipomeamarone and analyzing its radioauto-gram by silica gel thin layer chromatography of the extracts soluble in chloroformmethanol (1: 1 , v/v), after farnesol-2-14C feeding to the tissue. Further proof for farnesol-2-14C incorporation into ipomeamarone comes from the fact that the specific radioactivity of ipomeamarone semicarbazone was constant throughout the crystallizations. Fractionation of the label of farnesol-2-14C showed that radioactivity was little distributed in the methanol-water fraction and was mainly incorporated into ipomeamarone. Accordingly, it is not likely that farnesol is incorporated into ipomeamarone after its degradation to a small molecule(s) such as acetate. An additional experiment indicatedthat the incorporation of farnesol-2-14C into ipomeamarone markedly decreased under strict anaerobic conditions. This shows that some oxidative reactions are involved in ipomeamarone biosynthesis from farnesol.
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