CRISPR/Cas9 Mediated Disruption of Seminal Fluid Protein Sfp62 Induces Male Sterility in Bombyx mori

SIMPLE SUMMARY: In gamogenetic animals, seminal fluid proteins are essential for male fertility. In this study, we investigated the function of the seminal fluid protein Sfp62 by using the CRISPR/Cas9 system in lepidopteran model insect Bombyx mori. Sfp62 mutation led to male sterility and can be inherited stably. The mutation did not affect growth and developmental nor female fertility. These data indicate that Sfp62 is an ideal target for sterile insect technology (SIT), in which genetically modified insects are released on a large scale to mate with wild-type insects in order to reduce or even eradicate the target pests. The determining factors for the effective implementation of SIT include the strong competitiveness of the modified individuals and multi-generational effects resulting from the mutation. Sfp62 meets these criteria and is therefore a promising target for biological pest control. ABSTRACT: Seminal fluid proteins provide factors necessary for development, storage, and activation of sperm. Altered expression of seminal fluid proteins can lead to defect in male infertility. We investigated the function of seminal fluid protein Sfp62 in the model lepidopteran insect Bombyx mori using CRISPR/Cas9 mediated mutagenesis. The knockout of BmSfp62 gene led to male sterility but has no effect on female fertility. The mutation did not affect growth and development of the silkworm of both sexes. Motility of sperm in male mutants was decreased and the mRNA expression levels of other genes encoding seminal fluid proteins were altered in BmSfp62 mutants compared to the wild-type controls. The male sterility caused by mutation of BmSfp62 was stably inherited. As the proteins encoded by Sfp62 genes are conserved among lepidopteran species, Sfp62 is a potential target for the biological management of lepidopteran pests.