RNAi in termites (Isoptera): current status and prospects for pest management

Abstract

Termites are keystone species and play an essential role in the ecosystem by decomposing plants and wood materials with adapted endogenous and symbiotic cellulase systems to obtain food and energy. However, some termites are also pests that have significant economic impacts directly or indirectly on the agricultural system, such as pastures, orchards, nurseries, and eucalyptus forests, and globally the estimated loss is $40 billion annually. Recently, scientists have focused on RNAi technology to protect plants against insect pests, and the utilization of RNAi against termites is confounded because of their social nature and habitats. Many termite species transcriptomes and genome sequencing projects are cur-rently underway, and the outputs open new avenues for the species-specific design of RNAi-based termiticides. With these genomes, symbiotic biological agents such as fungi, bacteria, viruses, and nematodes can be screened and evaluated to express RNAi bioactive molecules (dsRNA, siRNA, and shRNA). In parallel, dsRNA/siRNA can also be delivered through nanocarriers against termites. In this perspective, we highlight existing RNAi-based functional genomic studies against eusocial termite pests and further discuss the prospects for RNAi-termiticides, considering unique challenges in terms of dsRNA delivery, target efficiency, environmental risks and termite eusociality.