Molecular and functional characterization of a β-tubulin gene in Plutella xylostella

The β-tubulin gene is essential for reproductive development, especially for male fertility, in different insects including Bombyx mori and Drosophila melanogaster. Targeting reproductive genes such as β-tubulin offers a promising approach to pest control that is more sustainable than chemical pesticides. However, there is limited research on the functional role of β-tubulin in Plutella xylostella, a highly damaging pest of vegetable crops. In the present study, we first identified and cloned the β-tubulin gene in P. xylostella (Pxβtubulin-1). Pxβtubulin-1 protein contains two conserved domains of Tubulin and Tubulin-C, and β-tubulin were conserved in the Lepidoptera. Spatiotemporal expression analysis revealed that Pxβtubulin-1 was highly expressed in male pupae, adult males, and testes, suggesting its testis-specific function. Using CRISPR/Cas9 technology, we generated two homozygous Pxβtubulin-1 mutant strains of P. xylostella. Mutant strains exhibited significantly lower egg production and hatching rates compared with the wild type. Dissection and measurement of reproductive organs revealed that the testes and bursa copulatrix in mutant strains were significantly reduced in size compared with the wild type. In conclusion, Pxβtubulin-1 is vital for male fertility as it influences the development of reproductive organs and can be a potential target for the control of P. xylostella.