Effect of receptor tyrosine kinase family member <i>CAD96CA</i> on hormone signalling and ontogeny of silkworm

Moulting and metamorphosis are fundamental physiological processes in the growth and development of holometabolous insects, primarily regulated by ecdysteroids and juvenile hormone (JH), which are synthesized and secreted by the prothoracic gland and corpora allata, respectively. However, the signalling regulatory network involved in the synthesis of these hormones and their effects is complex and interactive and involves many unidentified functional genes. In this study, we conducted a basic bioinformatics analysis of the CAD96CA gene and obtained CAD96CA mutants at the individual level in domestic silkworms using the CRISPR-Cas9 technology. We analysed the growth, development and silk protein synthesis phenotypes of the mutants and detected the synthesis and signalling effects of 20E and JH. The results revealed that knocking out the CAD96CA gene resulted in inhibited larval growth, reduced silk protein production, hindered larval-pupal transition and led to larval mortality. The synthesis of 20E and its signalling pathways, as well as the signalling pathways of JH, were all affected to varying degrees following CAD96CA knockout. Our study elucidates the role of CAD96CA in the growth and development of silkworms and provides a reference for studying metamorphosis mechanisms.