The Arabidopsis dwf7/ste1 mutant is defective in the Δ7 sterol C-5 desaturation step leading to brassinosteroid biosynthesis

Sunghwa Choe, Takahiro Noguchi, Shozo Fujioka, Suguru Takatsuto, Christophe P. Tissier, Brian D. Gregory, Amanda S. Ross, Atsushi Tanaka, Shigeo Yoshida, Frans E. Tax, Kenneth A. Feldmann

Research output: Contribution to journalArticlepeer-review

197 Scopus citations


Lesions in brassinosteroid (BR) biosynthetic genes result in characteristic dwarf phenotypes in plants. Understanding the regulation of BR biosynthesis demands continued isolation and characterization of mutants corresponding to the genes involved in BR biosynthesis. Here, we present analysis of a novel BR biosynthetic locus, dwarf7(dwf7). Feeding studies with BR biosynthetic intermediates and analysis of endogenous levels of BR and sterol biosynthetic intermediates indicate that the defective step in dwf7-1 resides before the production of 24-methylenecholesterol in the sterol biosynthetic pathway. Furthermore, results from feeding studies with 13C-labeled mevalonic acid and compactin show that the defective step is specifically the Δ7 sterol C-5 desaturation, suggesting that dwf7 is an allele of the previously cloned STEROL1 (STE1) gene. Sequencing of the STE1 locus in two dwf7 mutants revealed premature stop codons in the first (dwf7-2) and the third (dwf7-1) exons. Thus, the reduction of BRs in dwf7 is due to a shortage of substrate sterols and is the direct cause of the dwarf phenotype in dwf7.

Original languageEnglish (US)
Pages (from-to)207-221
Number of pages15
JournalPlant Cell
Issue number2
StatePublished - Feb 1999

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology


Dive into the research topics of 'The Arabidopsis dwf7/ste1 mutant is defective in the Δ<sup>7</sup> sterol C-5 desaturation step leading to brassinosteroid biosynthesis'. Together they form a unique fingerprint.

Cite this