Virus resistance and gene silencing in plants can be induced by simultaneous expression of sense and antisense RNA

TLDR

Transgenic plants expressing sense or antisense transgenes can exhibit extreme virus resistance and posttranscriptional gene silencing, suggesting a plant surveillance system that degrades both transgene and target RNAs. The authors present a model that explains the induction and execution of posttranscriptional gene silencing, integrating their data with previous studies. They achieved this by generating sense–antisense RNA duplexes through colocated sense and antisense genes, self‑complementary transcripts, or by crossing plants carrying complementary transgenes. Transforming plants with constructs that produce duplex‑forming RNAs conferred virus immunity or gene silencing.

Abstract

Many examples of extreme virus resistance and posttranscriptional gene silencing of endogenous or reporter genes have been described in transgenic plants containing sense or antisense transgenes. In these cases of either cosuppression or antisense suppression, there appears to be induction of a surveillance system within the plant that specifically degrades both the transgene and target RNAs. We show that transforming plants with virus or reporter gene constructs that produce RNAs capable of duplex formation confer virus immunity or gene silencing on the plants. This was accomplished by using transcripts from one sense gene and one antisense gene colocated in the plant genome, a single transcript that has self-complementarity, or sense and antisense transcripts from genes brought together by crossing. A model is presented that is consistent with our data and those of other workers, describing the processes of induction and execution of posttranscriptional gene silencing.