Disruption of a microvitellogenin gene impairs eggshell formation in Mythimna separata

Microvitellogenin (mVg) belongs to the lepidopteran-specific lipoprotein_11 super family and is thought to be involved in insect reproduction. However, the function of mVg in reproduction has not been established. In this study, we identified and characterized in , a destructive insect pest of grain crops. is comprised of a 1,310 bp ORF encoding 437 amino acids. Structural analysis showed that MsmVg contains three conserved domains in the lipoprotein_11 super family, including the all-α-N-terminal domain (NTD), a homologous domain (PPD), and an all-β-C-terminal domain (CTD). was highly expressed in mature female adults and enriched in the ovaries of three-day-old female adults. Disruption of by RNA interference did not change the expression of , vitellogenin () or the vitellogenin receptor () in fat bodies, but it inhibited their transcription in ovaries. Phenotype analysis showed that knockdown of did not affect yolk deposition in ovaries, but impaired eggshell formation and led to a reduction in the reproductive capacity. Furthermore, knockdown of significantly inhibited the expression of genes associated with eggshell formation ( and ). Taken together, these data suggest that plays an important role in female reproduction by affecting eggshell formation in . , which provides a potential target for managing this insect pest.