Genome-Wide Identification, Expression Profiling, and Characterization of Cyclin-like Genes Reveal Their Role in the Fertility of the Diamondback Moth.

Cyclin-like genes are primarily considered as cell cycle regulators and have shown to be crucial for insect growth, development, reproduction, and fertility. However, no research has been performed on the cyclin-like genes in the diamondback moth ( Plutella xylostella ). Here, we identified the 21 cyclin genes in the genome of P. xylostella and clustered them into four groups. Most cyclin genes showed a well-maintained gene structure and motif distribution within the same group. The putative promoter regions of cyclin genes contained several transcription binding factors related to reproduction, along with growth and development. Furthermore, 16 miRNAs were identified targeting the 13 cyclin genes. Transcriptome and quantitative real-time PCR (qRT-PCR)-based expression profiling of cyclin-like genes at different stages and tissues were evaluated, revealing that 16 out of 21 cyclin genes were highly expressed in reproductive tissues of adult females and males. The Cyclin B1 gene ( PxCyc B1 ) was only expressed in the ovary of the adult female and selected for the subsequent analysis. RNAi-mediated suppression of PxCyc B1 interrupted the external genitalia and length of the ovariole of female adults. Furthermore, the egg-laying capacity and hatching rate were also significantly decreased by suppressing the PxCyc B1 , indicating the importance of cyclin genes in the reproduction and fertility of P. xylostella . The current study explained the detailed genome-wide analysis of cyclin-like genes in P. xylostella , which provided a basis for subsequent research to assess the roles of cyclin genes in reproduction, and the cyclin gene may be considered an effective target site to control this pest.