Beld M et al. 1989
- Authors:
Beld M. Martin C. Huits H. Stuitje AR. Gerats AG.
- Title:
Flavonoid synthesis in Petunia hybrida: partial characterization of
dihydroflavonol-4-reductase genes.
- Reference location:
Plant Molecular Biology. 13(5):491-502, 1989 Nov.
- Abstract:
In this paper we describe the organization and expression of the genes
encoding the flavonoid-biosynthetic enzyme dihydroflavonol-4-reductase
(DFR) in Petunia hybrida. A nearly full-size DFR cDNA clone (1.5 kb),
isolated from a corolla-specific cDNA library was compared at the
nucleotide level with the pallida gene from Antirrhinum majus and at the
amino acid level with enzymes encoded by the pallida gene and the A1 gene
from Zea mays. The P. hybrida and A. majus DFR genes transcribed in
flowers contain 5 introns, at identical positions; the three introns of
the A1 gene from Z. mays coincide with the first three introns of the
other two species. P. hybrida line V30 harbours three DFR genes (A, B, C)
which were mapped by RFLP analysis on three different chromosomes (IV, II
and VI respectively). Steady-state levels of DFR mRNA in the line V30
follow the same pattern during development as chalcone synthase (CHS) and
chalcone flavanone isomerase (CHI) mRNA. Six mutants that accumulate
dihydroflavonols in mature flowers were subjected to Northern blot
analysis for the presence of DFR mRNA. Five of these mutants lack
detectable levels of DFR mRNA. Four of these five also show drastically
reduced levels of activity for the enzyme UDPG:
flavonoid-3-O-glucosyltransferase (UFGT), which carries out the next step
in flavonoid biosynthesis; these mutants might be considered as containing
lesions in regulatory genes, controlling the expression of the structural
genes in this part of the flavonoid biosynthetic pathway. Only the an6
mutant shows no detectable DFR mRNA but a wild-type level for UFGT
activity. Since both an6 and DFR-A are located on chromosome IV and DFR-A
is transcribed in floral tissues, it is postulated that the An6 locus
contains the DFR structural gene. The an9 mutant shows a wild-type level
of DFR mRNA and a wild-type UFGT activity.
This page is part of the
Snapdragon Home Page.
The URL of the Snapdragon Home Page is
http://www.mpiz-koeln.mpg.de/snapdragon/snapdragon.html
If you have any comments, additions or corrections to this page of general
interest you are invited to use the
Snapdragon Guest Book.
For personal comments please write to the author(s) of this page or to
Kurt Stueber.
This page has last been modified on May 26, 1997.