Transforming insect population control with precision guided sterile males with demonstration in\xa0flies

Nikolay P Kandul,Sean L Wu,Junru Liu,Omar S Akbari,John M Marshall,Hector M Sanchez C

doi:10.1038/s41467-018-07964-7

Nikolay P Kandul, Sean L Wu + Show 4 more

Open Access

https://doi.org/10.1038/s41467-018-07964-7

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Abstract

The sterile insect technique (SIT) is an environmentally safe and proven technology to suppress wild populations. To further advance its utility, a novel CRISPR-based technology termed precision guided SIT (pgSIT) is described. PgSIT mechanistically relies on a dominant genetic technology that enables simultaneous sexing and sterilization, facilitating the release of eggs into the environment ensuring only sterile adult males emerge. Importantly, for field applications, the release of eggs will eliminate burdens of manually sexing and sterilizing males, thereby reducing overall effort and increasing scalability. Here, to demonstrate efficacy, we systematically engineer multiple pgSIT systems in Drosophila which consistently give rise to 100% sterile males. Importantly, we demonstrate that pgSIT-generated sterile males are fit and competitive. Using mathematical models, we predict pgSIT will induce substantially greater population suppression than can be achieved by currently-available self-limiting suppression technologies. Taken together, pgSIT offers to potentially transform our ability to control insect agricultural pests and disease vectors.

Highlights

The sterile insect technique (SIT) is an environmentally safe and proven technology to suppress wild populations
100% females from crosses between each Cas[9] strain and dgRNAβTub,Tra (N = 24, n = 1697) or dgRNAβTub,Dsx protein—female (DsxF) (N = 24, n = 1791) were masculinized into sterile intersexes due to disruption of either tra or dsx, and 100% male offspring were sterile due to simultaneous disruption of βTubulin 85D (βTub) (N = 48, n = 4231). These findings demonstrate that the ability to form highly active Cas9-guide RNAs (gRNAs) complexes was not saturated by double-guide RNAs (dgRNAs), and the precision guided SIT (pgSIT) approach works reproducibly with unprecedented efficiency (Fig. 2a, b; Supplementary Table 3)
We found that the 100% of the dgRNAβTub,Sex Lethal (Sxl) knockout females perished during preadult stages with the majority dying during pupal transition (Supplementary Fig. 3; Supplementary Tables 4, 5)

Summary

Introduction

The sterile insect technique (SIT) is an environmentally safe and proven technology to suppress wild populations. Notwithstanding, current drive designs are limited by the rapid evolution of resistance[10], and future research is necessary to develop drives that can limit and overcome evolved resistance[11,12] While these discussions and developments are advancing, given the precision, simplicity, and efficiency of CRISPR, we aimed to develop a novel, safe, and controllable, noninvasive, CRISPR-based genetic technology that could be transferred across species and implemented worldwide in the short term to combat wild populations. Damaging agents for sterilization, substantially reducing overall fitness and mating competitiveness of released males To overcome these limitations, microbe-mediated infertility techniques such as Wolbachia-based incompatible insect technique (IIT)[18,19], and modern genetic SIT-like systems such as the release of insects carrying a dominant lethal (RIDL)[20], and other methodologies to release fertile males that genetically kill females such as female-specific RIDL (fsRIDL)[21], and autosomal-linked X-chromosome shredders[22] have been developed We show that pgSIT males are fit and can successfully compete for mates

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