miR-PC-3p-241582_34 Contributes to the Infection of Athetis lepigone by Regulating the Expression of <i>HSWP4</i> in Nosema bombycis

Athetis lepigone is a recurring\npest in the maize seedling stage under the wheat-maize no-tillage\ndirect seeding system in China’s summer maize region. Our previous\nresearch identified a highly pathogenic Nosema bombycis to A. lepigone, which spore wall\nprotein plays an important role in the infection process. However,\nthe regulatory mechanism of this spore wall protein is still unclear.\nIn this study, we explored the regulatory mechanism of miRNAs on spore\nwall proteins. Transcriptome sequencing results showed that expression\nof the spore wall protein, <i>HSWP4</i>, significantly increased\nin the germination group compared to dormancy group. Silencing of <i>HSWP4</i> reduced the number of microsporidian spores breaking\nthrough the midgut wall cells of A. lepigone. Association analysis of small RNA and mRNA revealed that the targeting\nsite of miR-PC-3p-241582_34 on <i>HSWP4</i> was located\nin the CDS region, and miR-PC-3p-241582_34 had a significant negative\nregulatory relationship with <i>HSWP4</i>. The dual luciferase\nreporter assay demonstrated that miR-PC-3p-241582_34 significantly\naffected the luciferase activity of the <i>HSWP4</i>-3′UTR\nexpression vector (<i>P</i> < 0.05). Delivery of miRNA\nmimics decreased the expression of <i>HSWP4</i> and inhibited\nthe behavior of microsporidian spores breaking through the midgut\nwall of A. lepigone. On the other hand,\ndelivery of inhibitors produced opposite results, indicating that\nthe miR-<i>HSWP4</i> pathway plays an important role in\nmicrosporidian infection of A. lepigone. This study provides a new theoretical basis for understanding the\npathogenic mechanism and gene regulation of microsporidia, as well\nas for the green control of A. lepigone.