Conserved motif pairs in CidA-CidB dictate Wolbachia-induced cytoplasmic incompatibility patterns

Insect incompatibility technology and population replacement strategies based on the principle of cytoplasmic incompatibility (CI) have been proven to be effective in controlling mosquito-borne diseases. However, the genetic diversity of Wolbachia and the species-specificity of mosquito vectors lead to a range of CI phenotypes in the infected hosts. As key proteins regulating the CI phenomenon, CI factors (including CidA and CidB) play a critical role in this process. Studies have shown that the diversity of CI factors is closely related to the diversity of CI phenotypes, although the molecular mechanisms remain unclear. In this study, we systematically analyzed the interactions between 21 CidA types (wPip (I-IV)) and 4 CidB types (wPip-I), and identified key interaction sites located in two distinct regions of their interaction interfaces. Each region is composed of two distinct amino acid motifs. This finding suggests that different types of CidA and CidB can form four different families, resulting in 16 distinct interaction patterns. By predicting the structure of representative CidA-CidB complexes, we further analyzed the specific amino acid interaction residues and confirmed that this interaction pattern is conserved between CidA (wPip (I-IV)) and CidB (wPip (I-III)). Our findings provide an important theoretical basis and technical platform for the artificial manipulation and regulation of Wolbachia-induced CI. This work offers a new direction for the precise cross-species control of CI factors through sequence- and structure-guided molecular modification and design.