RNAi targeting Myzus persicae (Hemiptera) stylet cuticle proteins reduces ZYMV transmission

Aphids are one of the most important groups of agricultural pests due to their ability to transmit a wide range of plant viruses. The development of more sustainable and specific methods for plant virus control is an ongoing and active avenue of research. In this study, we demonstrate by feeding dsRNA to aphids via artificial diet assay, the knockdown of two M. persicae (green peach aphid) stylet cuticle proteins (ST-1 and ST-2) implicated in the attachment and retention of the non-persistent, Potyviridae family member, zucchini yellow mosaic virus (ZYMV) (Potyvirus cucurbitaflavitesselati). We further enhanced ST-1 and ST-2 transcript knockdown by co-administering Nuclease dsRNA (NUC1/ -2_dsRNA) as an RNAi of RNAi approach, enhancing the survivability of orally co-delivered ST1 and ST2_dsRNA molecules against endonucleases in the aphid's midgut. Functionally, we successfully show significant knockdown of the ST1 and ST2 gene upon co-administered with Nuc1_dsRNA translates to a significant reduction of virus particle retention of up to 84% and 90%, respectively in aphids. Particle reduction translated to a 60 - 73% reduction in the infection rate when zucchini plants were challenged with treated aphids. This study demonstrates the successful application of an RNAi of RNAi approach to significantly disrupt the virus-vector interaction effectively reducing virus transmission to plants and laying a solid foundation towards effective multi-stage life cycle targeting with RNAi-based viricidal applications.