The Potential Role of the Piwi Gene in the Development and Reproduction of Plutella xylostella .

Piwi proteins play a significant role in germ cell development and the silencing of transposons in animals by associating with small non-coding RNAs known as Piwi-interacting RNAs (piRNAs). While the Piwi gene has been well characterized in various insect species, the role of the Piwi ( PxPiwi ) gene in the diamondback moth ( Plutella xylostella ), a globally distributed pest of cruciferous crops, remains unclear. Expression analysis demonstrated the upregulation of PxPiwi in pupae and testes. Furthermore, we generated a PxPiwi -knockout mutant using CRISPR/Cas9 technology, which resulted in a significantly prolonged pupal stage and the failure of pupae to develop into adults. Additionally, the knockdown of PxPiwi , through RNA interference (RNAi), led to a substantial decrease in the oviposition and hatchability of P. xylostella . These findings indicate that PxPiwi is specifically expressed and essential for the development and reproduction of P. xylostella . This is the first report indicating the involvement of the Piwi gene in the development of lepidopteran insects, except for reproduction and germ cell development, which provides a foundation for future investigations into the functions of PxPiwi .