Molecular and General Genetics MGG

, Volume 231, Issue 3, pp 345–352

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


  • Peter Meyer
    • Max-Delbrück-Laboratorium in der MPG
  • Felicitas Linn
    • Max-Planck-Institut für Züchtungsforschung
  • Iris Heidmann
    • Max-Delbrück-Laboratorium in der MPG
  • Heiner Meyer
    • Max-Delbrück-Laboratorium in der MPG
  • Ingrid Niedenhof
    • Max-Delbrück-Laboratorium in der MPG
  • Heinz Saedler
    • Max-Planck-Institut für Züchtungsforschung

DOI: 10.1007/BF00292701

Cite this article as:
Meyer, P., Linn, F., Heidmann, I. et al. Molec. Gen. Genet. (1992) 231: 345. doi:10.1007/BF00292701


30000 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.

Key words

A1 genePetunia hybridafield experimentDNA methylationEnvironment
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© Springer-Verlag 1992