Paper

White pupae genes in the Tephritids Ceratitis capitata, Bactrocera dorsalis and Zeugodacus cucurbitae: a story of parallel mutations

Leveque, Gary, Aumann, Roswitha A, Whitehead, Mark A, Nikolouli, Katerina, Caceres-Barrios, Carlos, Ragoussis, Ioannis, Fung, Elisabeth, Reiling, Sarah J, Geib, Scott, Schetelig, Marc F, Gouvi, Georgia, Choo, Amanda, Marec, Frantisek, Haecker, Irina, Bourtzis, Kostas, Baxter, Simon W, Whiteford, Sam, Sim, Sheina, Crisp, Peter, Darby, Alistair C, Hughes, Margaret A, Ngoc Minh Thu Nguyen, Ward, Christopher M, Haig Hugo Vrej Djambazian

2020

Overview

Flooding insect pest populations with huge numbers of sterilized males is an effective mean of biological control as they mate with, but cannot fertilize, wild females. The greatest challenge of the sterile insect technique (SIT) is the removal of unrequired factory reared females prior to sterilization and release. Spontaneous white-pupae (wp−) color mutations have been integrated as a dimorphic selectable marker into historical SIT strains for three major tephritid fruit fly pests, Bactrocera dorsalis, Ceratitis capitata and Zeugodacus cucurbitae. Here we identify parallel genetic mutations causing the phenotype in all three species using diverse experimental approaches. The B. dorsalis wp− locus was introgressed into a related species, Bactrocera tryoni, and whole-genome sequencing identified a 37 bp truncating mutation within a gene containing a Major Facilitator Superfamily domain (MFS). In C. capitata and Z. cucurbitae, cytogenetics, comparative genomics and transcriptomic analysis of strains carrying brown and white pupae phenotypes identified an 8,150 bp insertion of a putative transposon into the C. capitata MFS ortholog and a 13 bp deletion in the Z. cucurbitae ortholog. In B. tryoni CRISPR/Cas9-mediated knock-out of the putative Bt_wp developed mosaic white and brown puparium colors in G0, and G1 progeny with recessive white pupae phenotypes. In C. capitata, complementation crosses of CRISPR-induced wp− mutants to flies carrying the naturally occurring recessive wp− mutation confirmed the role of the gene. Gene editing technology carries the potential for engineering white pupae phenotypes and generating dimorphic SIT strains in other tephritids or insect pest species. Competing Interest Statement The authors have declared no competing interest.

• Publisher: Cold Spring Harbor Laboratory Press
• Subject: Bactrocera dorsalis / Bactrocera tryoni / Biological control / Ceratitis capitata / Complementation / CRISPR / Cytogenetics / Flooding / Genetic crosses / Genomics / Insertion / Mutation / Pest control / Pests / Phenotypes / Pupae / Species / Sterilization / Sterilized organisms / Whole genome sequencing / Zeugodacus cucurbitae