Scientists Review RNAi-induced Effects in GM Plants

Experts from Fraunhofer Institute for Molecular Biology and Applied Ecology and partners in Germany conducted a review to classify mechanisms of RNA interference (RNAi) effects induced by short interfering RNA from different sources in plants and to identify technologies that can be used to detect these effects. The review paper is published in the Frontiers in Plant Science.

Gene silencing through RNAi offers two main approaches: endogenous (host-induced gene silencing or HIGS) using genetically modified (GM) plants, and exogenous (spray-induced gene silencing or SIGS). Both rely on introducing double-stranded RNA (dsRNA), which is processed into short interfering RNAs (siRNAs) that silence specific messenger RNAs (mRNAs). However, potential risks include unintended effects on non-target organisms and the GM plants themselves, due to sequence similarities or siRNA-induced epigenetic changes. Regulatory bodies like the EPA and EFSA mandate thorough risk assessments. Detecting these unintended effects is challenging, often requiring bioinformatics and untargeted analyses such as transcriptomics and metabolomics, which depend on comprehensive genomic data.

According to the review, recent research suggests RNAi is relatively specific with few off-target effects in GM crops, but more studies are necessary to fully assess and mitigate potential risks. This is especially true for transcriptional gene silencing  which is less predictable than post-transcriptional gene silencing. Comprehensive risk assessments should include untargeted approaches like small RNA sequencing and transcriptomics.

Read more from Frontiers in Plant Science.