TRV-mediated VIGS in N. benthamiana. TRV-based virus induced gene silencing assay covers many steps; the gene with known sequence is first selected and then genetically engineered for cloning into pTRV2. pTRV1 consists of a TRV1-based cassette (RNA-dependent RNA polymerase gene, movement protein, etc.), LB and RB site for plant transformation. The plasmids are transformed into A. tumefaciens, and then agro-inoculation is applied. Agrobacterium can be inoculated on plant into seedling by a toothpick, a syringe and a vacuum infiltration as shown in the picture.