Inhibition of Rhopalosiphum maidis (Corn Leaf Aphid) Growth on Maize by Virus-Induced Gene Silencing with Sugarcane Mosaic Virus.

The corn leaf aphid (Rhopalosiphum maidis), a damaging pest of maize (Zea mays), is not controlled by the insecticidal proteins in commercially available transgenic crop varieties. One promising approach is to reduce aphid growth and fecundity by targeting the expression of essential genes using plant-mediated RNA interference (RNAi). Here we describe a method whereby Sugarcane Mosaic Virus (SCMV), a positive-strand RNA virus in the Potyviridae family, is used for virus-induced gene silencing (VIGS) of gene expression in R. maidis. A segment of the R. maidis target gene is cloned into SCMV, maize plants are infected with the transgenic virus, aphids are placed on the virus-infected plants and, after a few days of feeding, decreases in target gene expression and aphid reproduction are assessed. This VIGS method can be used for rapid screening of suitable RNAi targets for aphid pest control, as well as to study the in vivo function of specific aphid genes.