Biology subjects

Braswell, W. E.

Publications and source records attributed to Braswell, W. E..

3 recordsLinked to original sources

bioRxiv2024

A self-limiting Sterile Insect Technique alternative for Ceratitis capitata

Genetic biocontrol systems have broad applications in population control of insects implicated in both disease spread and food security. In this study we establish and characterise a novel split-CRISPR/Cas9 system we term Sex Conversion Induced by CRISPR (SCIC) in Ceratitis capitata (the Mediterranean fruit fly), a major agricultural pest with a global distribution. Using the white eye gene for toolkit selection, we achieved up to 100% CRISPR/Cas9 efficiency, displaying the feasibility of C. capitata split-CRISPR/Cas9 systems using constitutive promoters. We then induce sex-conversion by targeting the transformer gene in a SCIC approach aimed for SIT-mediated releases upon radiation-based sterilisation. Knock-out of transformer induced partial to full female-to-male sex-conversion, with remaining individuals all being intersex and sterile. SCIC population modelling shows superior performance to traditional population control strategies, allowing for faster population elimination with fewer released sterile males. Our results build the foundation for further genetic pest control methods of C. capitata and related tephritid agricultural pests. Significance statementAgricultural industry faces increasing threat from a multitude of pests including the domineering tephritid fruit flies. Genetic engineering of these pests has been recently tested to develop more efficient and affordable population control strategies. Here, we develop a new approach to improve existing population control measures by testing it in one of the most famous and dangerous tephritids, the Mediterranean fruit fly. Through optimisation, we achieved desired outcomes: female fly absence achieved via semi and full female-to-male sex conversion by CRISPR-mediated genome editing through gene mutations. For the first time in this insect, we used a split, and thus inducible, approach for such genome editing. Our work holds the potential to significantly improve tephritid population control strategies.

genetics↗

bioRxiv2023

Next-generation genetic sexing strain establishment in the agricultural pest Ceratitis capitata

Tephritid fruit fly pests pose an increasing threat to the agricultural industry due to their global dispersion and a highly invasive nature. Here we showcase the feasibility of an early-detection SEPARATOR sex sorting approach through using the non-model Tephritid pest, Ceratitis capitata. This system relies on female-only fluorescent marker expression, accomplished through the use of a sex-specific intron of the highly-conserved transformer gene from C. capitata and Anastrepha ludens. The herein characterized strains have 100% desired phenotype outcomes, allowing accurate male-female separation during early development. Overall, we describe an antibiotic and temperature-independent sex-sorting system in C. capitata, which, moving forward, may be implemented in other non-model Tephritid pest species. This strategy can facilitate the establishment of genetic sexing systems with endogenous elements exclusively, which, on a wider scale, can improve pest population control strategies like sterile insect technique.

bioengineering↗

bioRxiv2023

CRISPR-based diagnostics detects invasive insect pests

Rapid identification of organisms is essential across many biological and medical disciplines, from understanding basic ecosystem processes and how organisms respond to environmental change, to disease diagnosis and detection of invasive pests. CRISPR-based diagnostics offers a novel and rapid alternative to other identification methods and can revolutionize our ability to detect organisms with high accuracy. Here we describe a CRISPR-based diagnostic developed with the universal cytochrome-oxidase 1 gene (CO1). The CO1 gene is the most sequenced gene among Animalia, and therefore our approach can be adopted to detect nearly any animal. We tested the approach on three difficult-to-identify moth species (Keiferia lycopersicella, Phthorimaea absoluta, and Scrobipalpa atriplicella) that are major invasive pests globally. We designed an assay that combines recombinase polymerase amplification (RPA) with CRISPR for signal generation. Our approach has a much higher sensitivity than other real time-PCR assays and achieved 100% accuracy for identification of all three species, with a detection limit of up to 120 fM for P. absoluta and 400 fM for the other two species. Our approach does not require a lab setting, reduces the risk of cross-contamination, and can be completed in less than one hour. This work serves as a proof of concept that has the potential to revolutionize animal detection and monitoring.

genetics↗