Molecular characterization of Vitellogenin-like1 gene in Sogatella furcifera (Hemiptera: Delphacidae), and its function on reproduction.

In this study, a vitellogenin like1 gene (SfVg-like1) in Sogatella furcifera was identified. The open reading frame (ORF) encoded 1,321 amino acid sequence. Structure analysis reveals that the amino acid sequence of SfVg-like1 has 3 conserved LPD_N, DUF1943 and VWFD domains. Phylogenetic analyses showed that SfVg-like1 was clustered in the same branch with the Vg-like1 of Nilaparvata lugens (100% bootstrap value) compared with other Hemiptera insects Vgs associated with vitellogenesis. Temporo-spatial expression analyses showed that SfVg-like1 expressed during all stages, and in both genders. The relative expression levels of SfVg-like1 mRNA were higher in adults than in nymph developmental stages. The knockdown of SfVg-like1 gene resulted in the inhibition of the ovarian development in female adults, whereas the morphology of the testis in male adults was not been affected. The silence of SfVg-like1 could decrease the relative expression levels of target of rapamycin (SfTOR, GenBank MW193765) and vitellogenin (SfVg, GenBank MH271114) genes significantly in female adults. However, the knockdown of SfTOR or SfVg genes in female adults did not affect the transcript level of SfVg-like1. Therefore, it demonstrated that SfVg-like1 might locate on the upstream signaling pathways of SfTOR and SfVg. These results demonstrate that SfVg-like1 is essential for S. furcifera reproduction, and it could be the potential target for the control of this pest.