18.コムギにおける環状ジテルペン生合成について(口頭発表)

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Previously, we isolated three cDNAs, TaCPS1 to 3, from wheat (Triticum aestivum). TaCPS1 and TaCPS2 were homologous to OsCPS2/OsCyc2 and OsCPS4/OsCyc1, both of which are responsible for phytoalexin biosynthesis in rice (Oryza sativa), and TaCPS3 was homologous to ent-copalyl diphosphate synthases for gibberellin biosynthesis in other plant species, including rice (OsCPS1). In the present study, we characterized TaCPS1 to 3. It was suggested that all of TaCPS1 to 3 encode ent-copalyl diphosphate synthases by in vitro assays using the recombinant enzymes. The transcript levels of TaCPS1 and TaCPS2 in the wheat leaves increased after UV treatment, while that of TaCPS3 was unaffected. However, the expression levels of TaCPS1 and TaCPS2 were extremely lower than that of TaCPS3, unlike the cases in rice. Therefore, we could detect no cyclic diterpene hydrocarbons in UV-treated wheat leaves by GC-MS analysis. Furthermore, it was confirmed that phytocassanes and momilactones, rice diterpene phytoalexins, were not detected in UV-treated wheat leaves. Nevertheless, our studies suggested that ancestor genes of OsCPS2/OsCyc2 and OsCPS4/OsCyc1 have been present in Graminae.
植物化学調節学会の論文
2008-10-06