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2C-S-1445 PDF
マススペクトルを活用したイネの二次代謝における多様性の解明
Plants accumulate diverse secondary metabolites to survive in their environment. We have studied the diversity of secondary metabolites (chemodiversity) in rice by using mass spectrometry, mainly LC-MS. Rice (Oryza sativa) is the crop domesticated from the ancestral wild species O. rufipogon, and rice cultivars were classified into three subgroups, japonica, indica, and aus. Reflecting complex domestication process and vast cultivation area, its secondary metabolism is considered to contain a great diversity.
We examined the differences in metabolite composition among the subgroups. We analyzed leaf extracts from various cultivars by LC-QTOF-MS, applied non-linear dimensionality reduction methods to the detected ions, and found the clusters corresponding to the subgroups. This finding indicated that the genetic difference among subgroups is reflected to metabolite composition.
Rice leaves accumulate antimicrobial compounds, phytoalexins, in response to pathogen attack. The phytoalexin contents were analyzed in various cultivars. Major phytoalexins, such as momilactone A and phytocassanes, are commonly accumulated, whereas other phytoalexins, oryzalexins and oryzalactone were cultivar specific. In addition, new cultivar specific phytoalexins, abietorysins, were indentifed.
These findings indicate that although rice is a single species, multiple chemotypes are present within the species, and that rice has the pronounced chemodiversity