RNAi-based bioinsecticide for Aedes mosquito control

Abstract

Zika virus infection and dengue and chikungunya fevers are emerging viral diseases that have become public health threats. Their aetiologic agents are transmitted by the bite of genus Aedes mosquitoes. Without effective therapies or vaccines, vector control is the main strategy for preventing the spread of these diseases. Increased insecticide resistance calls for biorational actions focused on control of the target vector population. The chitin required for larval survival structures is a good target for biorational control. Chitin synthases A and B (CHS) are enzymes in the chitin synthesis pathway. Double-stranded RNA (dsRNA)-mediated gene silencing (RNAi) achieves specific knockdown of target proteins. Our goal in this work, a new proposed RNAi-based bioinsecticide, was developed as a potential strategy for mosquito population control. DsRNA molecules that target five different regions in the CHSA and B transcript sequences were produced in vitro and in vivo through expression in E. coli HT115 and tested by direct addition to larval breeding water. Mature and immature larvae treated with dsRNA targeting CHS catalytic sites showed significantly decreased viability associated with a reduction in CHS transcript levels. The few larval and adult survivors displayed an altered morphology and chitin content. In association with diflubenzuron, this bioinsecticide exhibited insecticidal adjuvant properties.

Mosquito-Borne Diseases Emergence/Resurgence and How to Effectively Control It Biologically

“…Paratransgenic strategies based on genetically modified symbiotic bacteria reintroduced in mosquitoes reveal a very high potential of casually controlling all-important mosquito species, including Culex, which is difficult to transform [14]. New studies on RNAi-based bioinsecticides (RNA interference) show promising results [108].…”

“…Recently, a new RNAi-based bioinsecticide was developed from D-RNA molecules, which was subsequently tested on Aedes larval breeding water [108]. A significant reduction in the viability of the larvae treated with dsRNA was reported while in the surviving larvae and adults, altered morphology and chitin content was observed.…”

“…A significant reduction in the viability of the larvae treated with dsRNA was reported while in the surviving larvae and adults, altered morphology and chitin content was observed. In combination with diflubenzuron, this innovative bioinsecticide had insecticidal adjuvant properties [108].…”

Programmable CRISPR interference for gene silencing using Cas13a in mosquitoes

“…The last is perhaps the most immediately impactful, as, with increasing insecticide resistance, the array of options for vector control is shrinking and in dire need of replenishment. RNA interference (RNAi) based approaches have been widely used to identify genes that are relevant to vector competence, and RNAi-based effectors for mosquito control have been developed [1][2][3][4][5]. As an alternative or complement to RNAi-based tools, CRISPR-Cas9 based genome editing tools have been developed for gene function study in mosquito research field [6][7][8].…”

Programmable CRISPR interference for gene silencing using Cas13a in mosquitoes

“…RNA interference (RNAi) is a defense mechanism that eukaryotic organisms use to target invading RNA viruses. RNAi based approaches have been widely used in gene function study to identify genes that are relevant to vector competence, and recently has been developed into effectors for mosquito control [1][2][3][4][5] . The RNAi machinery consists of Dicer and RNA-inducible silencing complex (RISC).…”