Transgene silencing in the moss, Physcomitrella (Physcomitrium patens)

Gene targeting is a powerful tool for functional genetic analysis. It has proved especially effective in the model plant, Physcomitrella (Physcomitrium patens (Hedw.) Mitt.), in which integration of exogenous DNA into the genome occurs with very high efficiency at targeted positions by homologous recombination. Here, we present a preliminary characterisation of a poorly documented property of Physcomitrella targeted gene knockout lines, namely, silencing of reporter and selective marker genes of integrated targeting constructs. We discovered a high incidence of transgene silencing among Physcomitrella knockout lines and, as is the case in seed plants, cytosine (DNA) methylation of the transgenes is correlated with their silencing. Silencing in Physcomitrella is characterised by metastable epigenetic inheritance through repetitive mitosis and variable stability through meiosis.

Automated summary

This study provides a preliminary characterization of transgene silencing in Physcomitrella targeted gene knockout lines. The research reveals that cytosine methylation of transgenes is correlated with their silencing in Physcomitrella, and this silencing occurs through metastable epigenetic inheritance via repetitive mitosis and variable stability through meiosis.