Brassinosteroid-6-Oxidases from Arabidopsis and Tomato Catalyze Multiple C-6 Oxidations in Brassinosteroid Biosynthesis

• Yukihisa Shimada

  Plant Science Center, RIKEN, Wako-shi, Saitama 351–0198, Japan (Y.S., S.F., N.M., M.K., Y.K., S.Y.);

• Shozo Fujioka

  Plant Science Center, RIKEN, Wako-shi, Saitama 351–0198, Japan (Y.S., S.F., N.M., M.K., Y.K., S.Y.);

• Narumasa Miyauchi

  Plant Science Center, RIKEN, Wako-shi, Saitama 351–0198, Japan (Y.S., S.F., N.M., M.K., Y.K., S.Y.);

• Masayo Kushiro

  Plant Science Center, RIKEN, Wako-shi, Saitama 351–0198, Japan (Y.S., S.F., N.M., M.K., Y.K., S.Y.);

• Suguru Takatsuto

  Department of Chemistry, Joetsu University of Education, Joetsu-shi, Niigata 943–8512, Japan (S.T.);

• Takahito Nomura

  Department of Biosciences, Teikyo University, Utsunomiya 320–8551, Japan (T.N., T.Y.); and

• Takao Yokota

  Department of Biosciences, Teikyo University, Utsunomiya 320–8551, Japan (T.N., T.Y.); and

• Yuji Kamiya

  Plant Science Center, RIKEN, Wako-shi, Saitama 351–0198, Japan (Y.S., S.F., N.M., M.K., Y.K., S.Y.);

• Gerard J. Bishop

  Institute of Biological Sciences, The University of Wales, Cledwyn Building, Aberystwyth, Ceredigion SY23 3DD, United Kingdom (G.J.B.)

• Shigeo Yoshida

  Plant Science Center, RIKEN, Wako-shi, Saitama 351–0198, Japan (Y.S., S.F., N.M., M.K., Y.K., S.Y.);

抄録

Brassinosteroids (BRs) are steroidal plant hormones that are essential for growth and development. It has been proposed that BRs are synthesized via two parallel pathways, the early and late C-6 oxidation pathways according to the C-6 oxidation status. The tomato (Lycopersicon esculentum) Dwarf gene encodes a cytochrome P450 that has been shown to catalyze the C-6 oxidation of 6-deoxocastasterone to castasterone. We isolated an Arabidopsis ortholog (AtBR6ox gene) of the tomatoDwarf gene. The encoded polypeptide has characteristics of P450s and is classified into the CYP85 family. TheAtBR6ox and tomato Dwarf gene were expressed in yeast and the ability of the transformed yeast cells to metabolize 6-deoxo-BRs was tested. Metabolites were analyzed by gas chromatography-mass spectrometry. Both enzymes catalyze multiple steps in BR biosynthesis: 6-deoxoteasterone to teasterone, 3-dehydro-6-deoxoteasterone to 3-dehydroteasterone, 6-deoxotyphasterol to typhasterol, and 6-deoxocastasterone to castasterone. Our results indicate that the AtBR6ox gene and the tomatoDwarf gene encode steroid-6-oxidases and that these enzymes have a broad substrate specificity. This suggests that the BR biosynthetic pathway consists of a metabolic grid rather than two separate parallel pathways.

収録刊行物

• Plant Physiology

  Plant Physiology 126 (2), 770-779, 2001-06-01

  Oxford University Press (OUP)

キーワード

• Plant Science
• Genetics
• Physiology

詳細情報

• CRID: 1362544420521549824
• NII論文ID: 80012490525
• DOI: 10.1104/pp.126.2.770
• ISSN: 15322548
• ISSN: 00320889
• ISSN: http://id.crossref.org/issn/00320889
• Web Site: http://academic.oup.com/plphys/article-pdf/126/2/770/38680914/plphys_v126_2_770.pdf
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