Abstract
Since its discovery, RNA interference (RNAi, also known as gene silencing) has been a key tool to downregulate gene expression in plants for a range of applications, including protection against viruses. Many of these applications require the silencing of multiple genes concomitantly. Multi-gene silencing, however, can be difficult to achieve owing to challenges in generating single RNAi constructs targeting unrelated genes or due to molecular instability linked to those constructs. Here, we show that microRNA-induced gene silencing (MIGS) can overcome many of these limitations and can be an important tool for multi-gene silencing in plants. We demonstrate how MIGS targeting several genes enhances the RNAi-based inhibition of one or more viruses. We also define several key features for optimising the use of MIGS in plants, including modular design, effective targeting length and phased first-base composition.