Application of Virus-Induced Gene Silencing to Arbuscular Mycorrhizal Fungi

Downregulation of AM fungal genes using a plant viral vector is feasible. A partial sequence of a target gene is cloned into the multicloning site of the CMV2-A1 vector developed from RNA2 of Cucumber mosaic virus Y strain, and the RNA2, together with RNA1 and RNA3 of the virus, are in vitro-transcribed. Inoculation of Nicotiana benthamiana with these viral RNAs results in reconstitution of the virus in the plant, which triggers silencing of the fungal gene. Here, we describe not only the methods but also several tips for the successful application of virus-induced gene silencing to AM fungi.