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Brassinosteroid biosynthesis and inactivation
Author(s) -
Choe Sunghwa
Publication year - 2006
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2006.00681.x
Subject(s) - brassinosteroid , brassinolide , hydroxylation , biosynthesis , mutant , biochemistry , biology , enzyme , arabidopsis , cytochrome p450 , metabolic pathway , gene , botany , plant growth
The term brassinosteroids (BRs) refers to the growth‐promoting plant steroidal hormones. Various developmental programs including but not limited to cell elongation, stress tolerance, and skoto‐/photo‐morphogenesis are controlled by subnanomolar concentrations of BRs. Accordingly, BR mutants that are defective in BR biosynthetic or signaling pathways usually display dwarfism. Characterization of numerous BR dwarf mutants isolated from Arabidopsis , pea, tomato, and rice greatly contributed to our understanding of BR biology. Recently, an enzyme that mediates the final step in the BR biosynthetic pathways has been characterized by two different groups. The brassinolide synthases (Cytochrome P450s 85A2 and 85A3) are multifunctional enzymes that catalyze the last three consecutive steps in BR biosynthetic pathways, namely, C‐6 hydroxylation, dehydrogenation, and Baeyer‐Villiger type oxidation. In addition, many of the previously unknown steps have been genetically characterized. This review aims to summarize the knowledge that has been developed during the last 2–3 years in this field of BR biosynthesis and inactivation research.