Post‐transcriptional β‐1,3‐glucanase gene silencing involves increased transcript turnover that is translation‐independent

Abstract

Summary: In tobacco line T17, basic β‐1,3‐glucanases are silenced when a β‐1,3‐glucanase (gn1) transgene of Nicotiana plumbaginifolia is present in a homozygous condition. Co‐suppression of endogenous and transgenic basic β‐1,3‐glucanases occurs via a post‐transcriptional process. This study shows that silencing correlates with a reduced stability of the transcripts encoded by gn1 and the co‐suppressed endogenous glucanase genes. The observed decreases in mRNA stability at least partially explain the reductions in mRNA level. Furthermore, the results show that the enhanced, silencing‐related turnover of gn1 mRNA does not require continued protein synthesis. The implications of these findings for the mechanism of gene silencing are discussed.