Decoding and engineering temperature-sensitive lethality in <i>Ceratitis capitata</i> for pest control.

Abstract

The Sterile Insect Technique (SIT) is a species-specific and environmentally friendly method for effectively controlling pest insect populations based on releasing reared, sterile insects into infested areas. Sex sorting in rearing facilities, enabling male-only releases, is necessary to ensure SIT programs are efficient, cost-effective and, in case of mosquito control, also safe. This can be greatly facilitated by genetic sexing strains (GSS), exhibiting sex-specific phenotypic markers. However, the development of GSS remains challenging. The construction of a <i>temperature-sensitive lethal</i> (<i>tsl</i>)-based GSS in the Mediterranean fruit fly (<i>Ceratitis capitata</i>) over three decades ago was considered a major breakthrough for SIT programs but was never successfully replicated in other pests. After over 30 y of research, we have pinpointed a specific mutation in the <i>C. capitata lysine--tRNA ligase</i> (<i>Lysyl-tRNA synthetase</i>, <i>LysRS</i>) gene responsible for the tsl phenotype. Introducing this specific mutation into a wild-type strain produced full embryonic lethality under heat stress, replicating the original mutant phenotype. The random integration of a <i>LysRS</i> minigene reversed this effect. The high conservation of <i>LysRS</i> among insects suggests that tsl-based GSS could be expanded to multiple pest species and extend applications of SIT programs for disease prevention and the protection of agriculture.