A Transgene Locus is Required for Wavy-patterned Flowers of Transgenic Torenia Plants

Modification of flower colour in torenia ( Torenia fournieri Lind.) by reintroduction of the chalcone synthase (CHS) or dihydroflavonol-4-reductase genes has been reported (Aida et al ., 2000. Plant Science 153: 33–42). The typical modified phenotype among plants with an introduced antisense gene is a uniformly lighter-coloured corolla. Of the 67 plants in which an antisense CHS gene was introduced, only a single line (411-7) showed a wavy pattern on the flower lip. In flowers of this plant, the inner part of the corolla lip was pigmented more deeply than the outer part in a wave-like pattern—a pattern that does not exist in normal cultivars. The segregation ratio of the flower colour patterns of the offspring and Southern blot analysis demonstrated that one of the two transgene loci detected may cause the wavy phenotype; the other locus is never associated with the wavy phenotype but alone it could produce the typical antisense type pattern.