Abstract: 【Aim】This study aims to identify the G-protein β-subunit gene (NlGβ) in the brown planthopper, Nilaparvata lugens, and analyze its function, so as to supply a potential novel target gene for RNAi-based control of N. lugens. 【Methods】The coding sequence (CDS) of NlGβ of N. lugens was cloned and verified using PCR, and subjected to bioinformatics analysis. The spatiotemporal expression patterns of NlGβ were analyzed based on its transcriptome expression profiles in different developmental stages (egg, 1st-5th instar nymphs, and female and male adults) and adult tissues (head, leg, gut, cuticle, fat body, female reproductive system, and male reproductive system) of N. lugens. Microinjection of dsRNA against NlGβ was performed on the 2nd and 5th instar nymphs to silence NlGβ. Individual and female reproductive system phenotypes were observed, and the survival rate, number of eggs laid per female, and egg hatching rate were counted. Additionally, transmission electron microscopy was employed to observe the lateral oviduct intumescent region. 【Results】 The CDS of NlGβ (GenBank accession no.: XP_022200908.1) of N. lugens was 948 bp in length. The NlGβ protein comprised seven WD40 domains and four WD_REPEATS_1 motifs, indicating its conservation. Apart from the homologous proteins found in orthopteran insects, homologous NlGβs from other insect orders clustered well within the same evolutionary branch. The expression level of NlGβ exhibited periodic change during the 1st-3rd instar nymphal stages, and those in the 5th instar female nymphs and female adults were higher than those in the 5th instar male nymphs and male adults. NlGβ was expressed in various tissues of adults, with the highest expression level in the fat body, and the expression level of NlGβ in female reproductive system was higher than that in male reproductive system. Silencing NlGβ in the 2nd instar nymphs resulted in molting difficulty, leading to a significant decrease in the survival rate compared to the dsGFP control group. Silencing NlGβ in the 5th instar nymphs resulted in abnormal abdominal swelling in adult females, malformed ovarian development, a significant decrease in the number of eggs laid per female compared to the dsGFP control group, failure of egg hatching, an increase in secretion within the lateral oviduct intumescent region, and degradation of epithelial cells. 【Conclusion】 NlGβ is closely associated with the growth and development of N. lugens and the reproduction of its female individuals.

Key words: Nilaparvata lugens, G-protein β-subunit gene, molting, reproduction, RNA interference