TRANSCRIPTIONAL AND POSTTRANSCRIPTIONAL PLANT GENE SILENCING IN RESPONSE TO A PATHOGEN

Plants are able to respond to pathogen attack to restrain development of a systemic infection. The response of Brassica napus (oilseed rape) to systemic infection with the DNA virus cauliflower mosaic virus was shown to result in enhancement and subsequent suppression of viral ge ne expression in parallel with changes in symptom expression, Transgen es with homology to viral sequences were also affected, This phenomeno n, which was shown to be mediated by both transcriptional and posttran scriptional mechanisms, might be related to regulation of highly expre ssed genetic elements.