Successive silencing of tandem reporter genes in potato (Solanum tuberosum) over 5 years of vegetative propagation
Abstract
Transgenic plants represent an excellent tool for experimental plant biology and are an important component of modern agriculture. Transgenes can be silenced long after their integration.
To study the long-term changes in transgene expression in potato, the activity of two reporter genes, encoding GFP and NPTII, was monitored in a set of 17 transgenic lines over 5 years of vegetative propagation in vitro. Complete silencing of the reporter genes was observed in four lines (nearly 25 %), all of which successively silenced the two reporter genes, indicating an interconnection between their silencing.
We suggest a hypothetical mechanism involving the successive silencing of the two reporter genes that involves the switch of GFP silencing from the post-transcriptional to transcriptional level and subsequent spreading of methylation to the NPTII gene.