CRISPR-based gene drive targeting doublesex for fall armyworm population control

Overview

Fall armyworm (FAW), Spodoptera frugiperda, is a globally destructive invasive pest that has caused serious damage to maize production in China since 2019. This project develops a CRISPR/Cas9-based gene drive system targeting the doublesex (dsx) gene, a master regulator of sexual differentiation and reproduction in insects. By disrupting dsx function, the technology aims to suppress FAW populations through reduced reproductive capacity, providing a sustainable and species-specific alternative to conventional insecticide-based control.

The research team has already cloned the full-length Sfdsx gene and identified two alternatively spliced transcripts, SfdsxF (female) and SfdsxM (male), confirming its role in FAW reproductive development. The project seeks to construct a functional gene drive, validate its effect on population dynamics in caged and semi-field settings, and establish a foundation for future field deployment.

Technical specifications

Core approach:

• CRISPR/Cas9-mediated gene editing of the doublesex locus in fall armyworm
• Gene drive cassette designed to bias inheritance and spread the disruptive allele through wild populations
• Targeting of sex-specific splicing isoforms (SfdsxF and SfdsxM) to interfere with sexual differentiation and reproduction

Key capabilities established:

• Functional CRISPR/Cas9 editing system in FAW
• Full-length Sfdsx gene cloned and characterized
• Preliminary evidence of Sfdsx role in reproductive development

Planned validation steps:

• Phenotypic characterization of SfdsxF mutants (sexual morphology and reproductive capacity)
• Construction and assessment of Sfdsx-targeting gene drive in caged insect populations
• Semi-field evaluation of allele spread dynamics and impact on population reproduction

Partnership needs: deep sequencing analysis support, population genetics modeling expertise, and funding for key research personnel.

Technology readiness level

The technology is at an early-to-mid development stage (TRL 3–4). Laboratory validation of CRISPR/Cas9 editing in FAW and gene characterization have been completed. The next phase involves mutant phenotype analysis, gene drive construction, and controlled population assessments in cages and semi-field environments. The projected timeline for completion of validation studies is approximately one year. Full field deployment will require additional regulatory review and ecological risk assessment beyond the current project scope.