RNA interference of E75 nuclear receptor gene suppresses transmission of rice stripe virus in Laodelphax striatellus

Drosophila E75 belongs to the nuclear receptor superfamily and plays key role in various physiological processes including ecdysone signaling. We identified an orthologue of Drosophila E75 from the Laodelphax striatellus (LsE75). Open reading frame (ORF) of the LsE75 contains 2454 nucleotides and encodes a protein of 817 amino acids. A phylogenetic analysis showed that the LsE75 clustered within the insect E75 group and was most closely related to the E75 from hemipteran insects. Quantitative PCR analysis revealed that transcription of the LsE75 was highly increased in RSV-viruliferous L. striatellus compared to that in non-viruliferous L. striatellus. To inhibit transmission of the RSV in L. striatellus using RNAi pathway, dsRNA against LsE75 (dsLsE75) was exogenously applied to the insects. As a result, transcription of RSV NS3 gene in L. striatellus ingested dsLsE75 was reduced in dose-dependent manner, suggesting that transmission of the RSV could be suppressed by silencing of LsE75 transcription in RSV-viruliferous L. striatellus.