Abstract: This study systematically investigated the molecular characteristics, expression patterns of the vitellogenin (Vg) gene EonuVg, and its response to imidacloprid in Empoasca onukii. The full-length cDNA sequences of two EonuVg genes, EonuVg1 (PP128347) and EonuVg2 (PP128348) were cloned and designated. Their open reading frames (ORFs) are 6 066 bp and 6 138 bp, encoding 2 021 and 2 045 amino acids, respectively. Both proteins contain conserved structural domains of Vg, including a signal peptide, Vitellogenin-N superfamily (Vit-N), Vit_open_b-sht (Vit-b) and Von Willebrand factor type D (VWD) domains, along with insect-specific motifs such as N-terminal poly-serine tracts, an RNPR cleavage site, a GLCG conserved motif, and C-terminal cysteine residues. The RT-qPCR results show that EonuVg1 and EonuVg2 exhibited low expressions during the early developmental stages (eggs and nymphs), and their expression peaks appreared in the newly emerged female adults. Tissue-specific expression analysis shows that the two genes were highly expressed in the ovary and fat body. After silencing the two genes by RNAi technology, the female duration, oviposition duration and oviposition quantity show a downward trend, but there was no significant difference compared with the control group feeding with dsGFP. The results of imidacloprid stress experiment show that sublethal and higher concentrations of imidacloprid significantly downregulated the expressions of EonuVg1 and EonuVg2 in female adults. This study preliminarily discussed the possible function of EonuVgs in the development and their response to imidacloprid in E. onukii, which provided theoretical basis and data support for further study on the function of Vg genes.

Key words: Empoasca onukii, vitellogenin, expression pattern, sublethal concentration