LAUSR

BACKGROUND Mating and oviposition are essential and closely coordinated events in the reproduction of moths. Although tyramine, a biogenic amine, can affect insect reproduction by binding its receptors, the specific regulatory mechanism has not yet been fully elucidated. RESULTS Plutella xylostella mutant with TAR1 knockout (Mut7) was developed by the CRISPR/Cas9 system to investigate the effect of TAR1 knockout on the reproduction of the moth. Compared with wild-type (WT), the egg yield of Mut7F was significantly lower, no significant difference was observed in the egg size and hatching ratio between the groups. Further analysis showed that TAR1 knockout adversely affected ovary development, characterized by shorter ovarioles and fewer mature oocyte. Additionally, TAR1 knockout significantly reduced the occurrence of mating, resulting in a decrease in egg yield in Mut7F . The amounts of sex pheromones were quantified using a Gas Chromatography-Mass Spectrometer. Results showed that the amounts of sex pheromone released by Mut7F were significantly lower before mating. Correspondingly, the mRNA levels of sex pheromone biosynthesis enzymes, including acetyl-CoA carboxylase (ACC) and desaturase (DES), were significantly lower in the Mut7F pheromone gland. The decreased sex pheromone biosynthesis in Mut7F , especially before re-mating, may be related to the underexpression of pheromone biosynthesis-activating neuropeptide (PBAN). CONCLUSION Overall, this study investigated the effect of PxTAR1 on oviposition and mating of P. xylostella. We report for the first time that TAR1 knockout could reduce the sex pheromone biosynthesis. These findings provide insights for developing a novel integrated pest control strategy based on mating interference. This article is protected by copyright. All rights reserved.