Publications

• Stemar-13-ene synthase, a diterpene cyclase involved in the biosynthesis of the phytoalexin oryzalexin S in rice.

  Nemoto T., Cho E.-M., Okada A., Okada K., Otomo K., Kanno Y., Toyomasu T., Mitsuhashi W., Sassa T., Minami E., Shibuya N., Nishiyama M., Nojiri H., Yamane H.

  In suspension-cultured rice cells, diterpenoid phytoalexins are produced in response to exogenously applied elicitors. We isolated a cDNA encoding a diterpene cyclase, OsDTC2, from suspension-cultured rice cells treated with a chitin elicitor. The OsDTC2 cDNA was overexpressed in Escherichia coli ... >> More

  In suspension-cultured rice cells, diterpenoid phytoalexins are produced in response to exogenously applied elicitors. We isolated a cDNA encoding a diterpene cyclase, OsDTC2, from suspension-cultured rice cells treated with a chitin elicitor. The OsDTC2 cDNA was overexpressed in Escherichia coli as a fusion protein with glutathione S-transferase, and the recombinant OsDTC2 was indicated to function as stemar-13-ene synthase that converted syn-copalyl diphosphate to stemar-13-ene, a putative diterpene hydrocarbon precursor of the phytoalexin oryzalexin S. The level of OsDTC2 mRNA in suspension-cultured rice cells began to increase 3 h after addition of the elicitor and reached the maximum after 8 h. The expression of OsDTC2 was also induced in UV-irradiated rice leaves. In addition, we indicated that stemar-13-ene accumulated in the chitin-elicited suspension-cultured rice cells and the UV-irradiated rice leaves. << Less

  FEBS Lett. 571:182-186(2004) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Evident and latent plasticity across the rice diterpene synthase family with potential implications for the evolution of diterpenoid metabolism in the cereals.

  Morrone D., Hillwig M.L., Mead M.E., Lowry L., Fulton D.B., Peters R.J.

  The evolution of natural product biosynthetic pathways can be envisioned to occur via a number of mechanisms. In the present study we provide evidence that latent plasticity plays a role in such metabolic evolution. In particular, rice (Oryza sativa) produces both ent- and syn-CPP (copalyl diphosp ... >> More

  The evolution of natural product biosynthetic pathways can be envisioned to occur via a number of mechanisms. In the present study we provide evidence that latent plasticity plays a role in such metabolic evolution. In particular, rice (Oryza sativa) produces both ent- and syn-CPP (copalyl diphosphate), which are substrates for downstream diterpene synthases. In the present paper we report that several members of this enzymatic family exhibit dual reactivity with some pairing of ent-, syn- or normal CPP stereochemistry. Evident plasticity was observed, as a previously reported ent-sandaracopimaradiene synthase also converts syn-CPP into syn-labda-8(17),12E,14-triene, which can be found in planta. Notably, normal CPP is not naturally found in rice. Thus the presence of diterpene synthases that react with this non-native metabolite reveals latent enzymatic/metabolic plasticity, providing biochemical capacity for utilization of such a novel substrate (i.e. normal CPP) which may arise during evolution, the implications of which are discussed. << Less

  Biochem. J. 435:589-595(2011) [PubMed] [EuropePMC]

  This publication is cited by 4 other entries.

• Characterization of a rice gene family encoding type-A diterpene cyclases.

  Kanno Y., Otomo K., Kenmoku H., Mitsuhashi W., Yamane H., Oikawa H., Toshima H., Matsuoka M., Sassa T., Toyomasu T.

  We have previously isolated and characterized the rice (Oryza sativa) cDNAs, OsCyc1/OsCPS4, OsCyc2/OsCPS2, OsKS4, OsDTC1/OsKS7, OsDTC2/OsKS8 and OsKS10, which encode cyclases that are responsible for diterpene phytoalexin biosynthesis. Among the other members of this gene family, OsCPS1 and OsKS1 ... >> More

  We have previously isolated and characterized the rice (Oryza sativa) cDNAs, OsCyc1/OsCPS4, OsCyc2/OsCPS2, OsKS4, OsDTC1/OsKS7, OsDTC2/OsKS8 and OsKS10, which encode cyclases that are responsible for diterpene phytoalexin biosynthesis. Among the other members of this gene family, OsCPS1 and OsKS1 have been suggested as being responsible for gibberellin biosynthesis, OsKSL11 has recently been shown to encode stemodene synthase, and the functions of the three other diterpene cyclase genes in the rice genome, OsKS3, OsKS5 and OsKS6, have not yet been determined. In this study, we show that recombinant OsKS5 and OsKS6 expressed in E. coli converted ent-copalyl diphosphate into ent-pimara-8(14),15-diene and ent-kaur-15-ene, respectively. Neither product is a hydrocarbon precursor required in the biosynthesis of either gibberellins or phytoalexins. OsKS3 may be a pseudogene from which the translated product is a truncated enzyme. These results suggest that the diterpene cyclase genes responsible for gibberellin and phytoalexin biosynthesis are not functionally redundant. << Less

  Biosci. Biotechnol. Biochem. 70:1702-1710(2006) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Diterpene cyclases responsible for the biosynthesis of phytoalexins, momilactones A, B, and oryzalexins A-F in rice.

  Otomo K., Kanno Y., Motegi A., Kenmoku H., Yamane H., Mitsuhashi W., Oikawa H., Toshima H., Itoh H., Matsuoka M., Sassa T., Toyomasu T.

  Rice (Oryza sativa L.) produces diterpene phytoalexins, such as momilactones, oryzalexins, and phytocassanes. Using rice genome information and in vitro assay with recombinant enzymes, we identified genes (OsKS4 and OsKS10) encoding the type-A diterpene cyclases 9beta-pimara-7,15-diene synthase an ... >> More

  Rice (Oryza sativa L.) produces diterpene phytoalexins, such as momilactones, oryzalexins, and phytocassanes. Using rice genome information and in vitro assay with recombinant enzymes, we identified genes (OsKS4 and OsKS10) encoding the type-A diterpene cyclases 9beta-pimara-7,15-diene synthase and ent-sandaracopimaradiene synthase which are involved in the biosynthesis of momilactones A, B and oryzalexins A-F respectively. Transcript levels of these two genes increased remarkably after ultraviolet (UV) treatment, which is consistent with elevated production of phytoalexins by UV. These two genes might prove powerful tools for understanding plant defense mechanisms in rice. << Less

  Biosci. Biotechnol. Biochem. 68:2001-2006(2004) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.