PLANT PHYSIOLOGY , Vol 104, Issue 4 1167-1176, Copyright © 1994 by American Society of Plant Biologists
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MOLECULAR BIOLOGY AND GENE REGULATION |
Temporal and Tissue-Specific Regulation of a Brassica napus Stearoyl-Acyl Carrier Protein Desaturase Gene
S. P. Slocombe, P. Piffanelli, D. Fairbairn, S. Bowra, P. Hatzopoulos, M. Tsiantis and D. J. Murphy
Brassica and Oilseeds Research Department, Cambridge Laboratory, John Innes Centre, Norwich NR4 7UJ, United Kingdom
The nucleotide sequence of a Brassica napus stearoyl-acyl carrier protein
desaturase gene (Bn10) is presented. This gene is one member of a family of
four closely related genes expressed in oilseed rape. The expression of the
promoter of this gene in transgenic tobacco was found to be temporally
regulated in the developing seed tissues. However, the promoter was also
particularly active in other oleogenic tissues such as the tapetum and
pollen grains. This raises the interesting question of whether
seed-expressed lipid synthesis genes are regulated by separate
tissue-specific determinants or by a single factor common to all oleogenic
tissues. Parts of the plants undergoing rapid development such as the
components of immature flowers and seedlings also exhibited high levels of
promoter activity. These tissues are likely to have an elevated requirement
for membrane lipid synthesis. Stearoyl-acyl carrier protein desaturase
transcript levels have previously been shown to be temporally regulated in
the B. napus embryo (S.P. Slocombe, I. Cummins, R.P. Jarvis, D.J. Murphy
[1992] Plant Mol Biol 20: 151-155). Evidence is presented demonstrating the
induction of desaturase mRNA by abscisic acid in the embryo.
