Homozygous transgenic wheat plants with increased luciferase activity do not maintain their high level of expression in the next generation

In an effort to assess transgene expression and stability in wheat (Triticum aestivum L.), we followed expression of the luciferase gene through T-1 and T-2 generations. We showed that only 48% of T-1 homozygous plants expressed the luciferase gene at double the level of hemizygous plants. The homozygous state of these T-1 plants was confirmed by studying the segregation of the transgene in the next generation and by using fluorescence in situ hybridisation. We showed that in all homozygous T-1 plants showing transgene dosage, the level of luciferase expression was reduced in the next generation. On the contrary, all T-1 low expressing plants conserved their expression levels in T-2 generation. Possible reasons for this reduction in transgene activity are discussed. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.