Brassinolide and [26, 28-2H6]brassinolide are differently demethylated by loss of C-26 and C-28, respectively, in Marchantia polymorpha.

Metabolism of brassinolide in Marchantia polymorpha was investigated by use of in vivo suspension cultured cells. GC-MS analysis of metabolites derived from non-labelled brassinolide and [26, 28-2H6] brassinolide revealed that brassinolide was converted to 26-norbrassinolide while [26, 28-2H6]brassinolide to [26-2H3]28-norbrassinolide. It seems that Marchantia cells recognized [26, 28-2H6]brassinolide as a xenobiotic rather than brassinolide and deteriums attached to C-28 significantly affect demethylation reaction due to isotopic effect. Thus, demethylation of brassinolide in planta seems to proceed by loss of C-26 rather than C-28. The present finding is the first evidence for demethylation metabolism of brassinosteroids. The biological activity of 26-norbrassinolide was 10-fold reduced as shown by the rice lamina inclination test. However, because of its high biological activity, it remains difficult to conclude whether or not C-26 demethylation serves as an important deactivation process of brassinolide.

[1]  J. Chory,et al.  BAS1: A gene regulating brassinosteroid levels and light responsiveness in Arabidopsis. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[2]  G. Adam,et al.  Inactivation of Brassinosteroid Biological Activity by a Salicylate-inducible Steroid Sulfotransferase from Brassica napus * , 1999, The Journal of Biological Chemistry.

[3]  S. Fujioka,et al.  Synthesis and biological evaluation of extra-hydroxylated brassinolide analogs , 1999 .

[4]  T. Altmann.  Molecular physiology of brassinosteroids revealed by the analysis of mutants , 1999, Planta.

[5]  Seung-Hyun Park,et al.  In Vivo and in Vitro Conversion of Teasterone to Typhasterol in Cultured Cells of Marchantia polymorpha , 1999 .

[6]  S. Clouse.  Molecular genetic analysis of brassinosteroid action , 1997 .

[7]  J. Winter,et al.  Role of a cytochrome P450-dependent monooxygenase in the hydroxylation of 24-epi-brassinolide , 1997 .

[8]  T. Yokota.  The structure, biosynthesis and function of brassinosteroids , 1997 .

[9]  B. Schneider.  New Developments in Brassinosteroid Research , 1996 .

[10]  A. Porzel,et al.  Metabolism of 24-epi-castasterone in cell suspension cultures of Lycopersicon esculentum , 1996 .

[11]  A. Porzel,et al.  Metabolism of 24-epi-castasterone and 24-epi-brassinolide in cell suspension cultures of Ornithopus sativus , 1996 .

[12]  S. Fujioka,et al.  Biological Activities of Biosynthetically-related Congeners of Brassinolide , 1995 .

[13]  B. Schneider,et al.  Metabolic conversion of 24-epi-brassinolide into pentahydroxylated brassinosteroid glucosides in tomato cell cultures , 1995 .

[14]  S. Takatsuto.  Brassinosteroids: Distribution in plants, bioassays and microanalysts by gas chromatography—mass spectrometry , 1994 .

[15]  Hiroyuki Suzuki,et al.  Metabolism of castasterone and brassinolide in mung bean explant , 1993 .

[16]  T. Yokota,et al.  Transport and metabolism of brassinosteroids in rice , 1992 .

[17]  C. M. Karssen,et al.  Progress in Plant Growth Regulation , 1992, Current Plant Science and Biotechnology in Agriculture.

[18]  Seong-Ki Kim.  Natural Occurrences of Brassinosteroids , 1991 .

[19]  T. Yokota,et al.  Brassinosteroids. Chemistry, bioactivity, and applications. , 1991 .

[20]  Judith L. Flippen-Anderson,et al.  Plant Growth-Promoting Brassinosteroids , 1988 .

[21]  A. Reuben.  Sterols and bile acids , 1987 .

[22]  T. Goodwin.  Chapter 7 Biosynthesis of plant sterols , 1985 .

[23]  H. Rilling,et al.  Chapter 1 Biosynthesis of cholesterol , 1985 .

[24]  T. Yokota,et al.  Identification and quantification of brassinolide-related steroids in the insect gall and healthy tissues of the chestnut plant , 1984 .

[25]  J. C. Cook,et al.  Brassinolide, a plant growth-promoting steroid isolated from Brassica napus pollen , 1979, Nature.

[26]  L. Goad.  The Biosynthesis of Plant Sterols , 1977 .

[27]  Michael W. King.  BIOSYNTHESIS of cholesterol. , 1953, Journal of the American Medical Association.

[28]  N. Werthessen,et al.  Biosynthesis of cholesterol; factors regulating biosynthesis of cholesterol-like substances in isolated whole livers. , 1952, The American journal of physiology.