CRISPR/Cas9-Mediated Vitellogenin Receptor Knockout Leads to Functional Deficiency in the Reproductive Development of .

The vitellogenin receptor (VgR) belongs to the low-density lipoprotein receptor (LDLR) gene superfamily and plays an indispensable role in Vg transport, yolk deposition, and oocyte development. For this reason, it has become a promising target for pest control. The involvement of in Vg transport and reproductive functions remains unclear in diamondback moths, (L.), a destructive pest of cruciferous crops. Here, we cloned and identified the complete cDNA sequence of , which encoded 1805 amino acid residues and contained four conserved domains of LDLR superfamily. was mainly expressed in female adults, more specifically in the ovary. VgR protein also showed the similar expression profile with the transcript. CRISPR/Cas9-mediated knockout created a homozygous mutant of with 5-bp-nucleotide deletion in the . The expression deficiency of VgR protein was detected in the ovaries and eggs of mutant individuals. Vg protein was still detected in the eggs of the mutant individuals, but with a decreased expression level. However, transcripts were not significantly affected by the knockout. Knockout of resulted in shorter ovarioles of newly emerged females. No significant difference was detected between wild and mutant individuals in terms of the number of eggs laid in the first 3 days after mating. The loss of gene resulted in smaller and whiter eggs and lower egg hatching rate. This study represents the first report on the functions of in Vg transport, ovary development, oviposition, and embryonic development of using CRISPR/Cas9 technology. This study lays the foundation for understanding molecular mechanisms of reproduction, and for making use of as a potential genetic-based molecular target for better control of the