Comparative transcriptome analysis reveals PERP upregulated during Salmonella Enteritidis challenge in laying ducks.

Salmonella Enteritidis (SE) can be transmitted to eggs through cecum or the ovary from infected layers and causes food poisoning in humans. The mechanism of cecal transmission has been extensively studied. However, the mechanism and route of transovarian transmission of SE remain unclear. In this study, the ducks were orally inoculated with SE, and the ovarian follicles and stroma were collected to detect SE infection. The immune responses were triggered and the innate and adaptive immune genes (TLR4, NOD1, AvβD7, and IL-1β) were upregulated significantly during the SE challenge. Moreover, the ovary tissues (small follicle and stroma) of susceptible and resistant-laying ducks were performed by RNA sequencing. We obtained and identified 23 differentially expressed genes (DEGs) between susceptible and resistant-laying ducks in both small follicle and stroma tissues ( p < 0.05). The DEGs were predominately identified in the p53 signaling pathway. The expression of key genes (p53, MDM2, PERP, caspase-3, and Bcl-2) involved in the signaling pathway was significantly higher in granulosa cells (dGCs) from SE-infected ducks than those from uninfected ducks. Moreover, the overexpression of PERP resulted in further induction of p53, MDM2, caspase-3, and Bcl-2 during SE infection in dGCs. Whereas, an opposite trend was observed with the knockdown of PERP. Besides, it is further revealed that the PERP could enhance cell apoptosis, SE adhesion, and SE invasion in SE-infected dGCs overexpression. Altogether, our results demonstrate the duck PERP involved in the ovarian local immune niche through p53 signaling pathway in dGCs challenged with SE.