DsRNA as pathogen-associated molecular pattern in innate immunity and multiple functions of the RNAi machinery complicate the use of RNAi in pest control

Summary

In contrast to mammals, insects possess a separate machinery for processing of long dsRNAs into siRNAs for the cleavage of viral RNAs. The process of RNAi is considered very efficient in all insects once the delivery in the cytoplasm occurs such as during RNA virus replication. For the application of RNAi as insecticide to succeed, efficient uptake of intact dsRNA into the cytoplasm therefore is necessary, which seems to occur by natural mechanisms in the leaf beetles for which RNAi-based insecticides already have been marketed. In most insects, relatively high amounts of dsRNA are required to trigger gene silencing which raises questions regarding potential side effects. Besides, RNAi is considered as the major antiviral defense mechanism, at least in <i>Drosophila</i>, but not necessaril