Reference "Endogenous and environmental factors influence 35S promoter methylation of a maize A1 gene construct in transgenic petunia and its colour phenotype"

Reference ID

7171

Title

Endogenous and environmental factors influence 35S promoter methylation of a maize A1 gene construct in transgenic petunia and its colour phenotype

Source

Molecular & General Genetics, 1992, vol. 231, pp. 345-352

Authors (6)

Meyer-P	Linn-F
Heidmann-I	Meyer-H
Niedenhof-I	Saedler-H

Abstract

30,000 transgenic petunia plants carrying a single copy of the maize A1 gene,
encoding a dihydroflavonol reductase, which confers a salmon red flower colour
phenotype on the petunia plant, were grown in a field test. During the growing
season plants with flowers deviating from this salmon red colour, such as those
showing white or variegated phenotypes and plants with flowers exhibiting only
weak pigmentation were observed with varying frequencies. While four white
flowering plants were shown at the molecular level to be mutants in which part
of the A1 gene had been deleted, other white flowering plants, as well as 13
representative plants tested out of a total of 57 variegated individuals were
not mutants but rather showed hypermethylation of the 35S promoter directing A1
gene expression. This was in contrast to the homogeneous fully red flowering
plants in which no methylation of the 35S promoter was observed. While blossoms
on plants flowering early in the season were predominantly red, later flowers on
the same plants showed weaker coloration. Once again the reduction of the A1-
specific phenotype correlated with the methylation of the 35S promoter. This
variation in coloration seems to be dependent not only on exogenous but also on
endogenous factors such as the age of the parental plant from which the seed was
derived or the time at which crosses were made.