Identification and Functional Insights of Knickkopf Genes in the Larval Cuticle of .

The Colorado potato beetle () is a major pest of potato crops. While () genes are essential for insect cuticle formation, their roles in pests like remain unclear. This study aims to identify and characterize genes in and explore their functions in larval development and cuticle integrity. We used genomic and transcriptomic databases to identify -family genes, validated through RT-PCR and RACE. Gene expression was analyzed at various developmental stages and tissues using qRT-PCR. RNA interference (RNAi) and Transmission electron microscopy (TEM) were applied to determine the functional roles of these genes. Four -family genes were identified. Spatio-temporal expression analysis indicated significant gene expression during larval molting and pupal stages, especially in the epidermis. RNAi experiments showed that silencing and ' led to reduced larval weight, cuticle thinning, and increased mortality, while knockdown caused abnormal cuticle thickening and molting disruptions. knockdown increased epicuticle and endocuticle thickness without visible phenotypic changes. The study highlights the essential roles of -family genes in maintaining cuticle structure and integrity, suggesting their potential as targets for RNAi-based pest control.