Biosyn this of Brassinosteroids in Plant

Research Project

Project/Area Number	60560131
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	製造化学・食品
Research Institution	THE UNIVERSITY OF TOKYO
Principal Investigator	YOKOTA TAKAO The University of Tokyo, DEPT OF AGRICULTURE, 農学部, 助手 (40011986)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥1,500,000 (Direct Cost: ¥1,500,000) Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000) Fiscal Year 1985: ¥1,200,000 (Direct Cost: ¥1,200,000)
Keywords	Brassinosteroid / Brassinolide / Castasterone / Biosynthesis / 代謝
Research Abstract	Tritium-labelled brassinolide and castasterone were prepared by reduction of dolicholide and dolichosterone respectively. Radioactive reduction products were purified by thin-layer and high performanceliquid chromatography, affording radio-labelled brassinolide and castasterone: specipic radioactivity of them was about 4Ci/mM. 3-leaf-stage rice seedlings were fed with ( <^3H> )castasterone for 6 hr through the roots. Portion of the treated seedlings were further incubated for 10 days in castasterone-free medium. These plant materials were analysed for the metabolites of castasterone. Thus, it was found that castasterone is absorbed by roots and transported to shoots. It was also found that castasterone was found to be rapidly converted into water-soluble metabolites. The structures of them seemed to be acidic conjugates rather than glycosides on the basis of chromatographic analysis and hydrolysis. Ten days after the treatment, most of castasterone absorbed was changed into polar metabolites, while unchanged castasterone accounted for only 0.43%. Castasterone, a hypothetical precursor of brassinolide was never changed into brassinolide. Fate of ( <^3H> )brassinlode was similarly pursued and the result was analogous to that of castasterone.