Systematic identification and evolutionary analysis of cytochrome P450 genes in Platanus acerifolia induced by Corythucha ciliata damage

The sycamore lace bug Corythucha ciliata (say) is the most important pest attacked the London planetree Platanus acerifolia worldwide. We propose that plant cytochrome P450s (CYP450s) are important and play key roles in P. acerifolia and C. ciliata interactions. Therefore, the identification of transcriptionally active CYP450 genes is considered essential for revealing the mechanisms involved in their interactions. So far, the CYP450 genes of P. acerifolia have not yet been reported. In this study, we identified and characterized 96 CYP450 genes in P. acerifolia. These genes were categorized into 8 clans, 41 families, and 60 subfamilies. Notably, 48 genes demonstrated a strong negative selection when compared with the CYP450 genes of Arabidopsis thaliana. The results of post-feeding induction of P. acerifolia by C. ciliata revealed ten CYP450 genes, which exhibited significant up-regulation. Gene expression levels of several identified CYP450 genes were validated by quantitative RT- PCR. Further, a putative allene oxide synthase gene encoding the key enzyme involved in the jasmonic acid biosynthesis (PaCYP74A187) was cloned, homology modeled, and subjected to molecular docking analysis. We propose PaCYP74A187 as a key candidate CYP450 gene in P. acerifolia induced by C. ciliata damage, altogether our findings enhance comprehensive understanding of the mechanisms associated with insect-plant interactions that will undoubtedly offer new targets for controlling C. ciliata populations.