Ecdysone receptor suppression affects chromatin-associated transcriptional programs during vitellogenesis in the black tiger shrimp Penaeus monodon

Ecdysone is a major steroid hormone regulating growth, molting, and reproduction in arthropods; however, its role in crustacean ovarian development remains still not fully understood. Here, we investigated ovarian regulatory mechanisms downstream of the ecdysone receptor (EcR) in the black tiger shrimp Penaeus monodon. Building on our previous finding that EcR negatively regulates Vg expression, we sought to characterize this inhibitory mechanism during shrimp vitellogenesis. Together with previous evidence implicating EcR in the regulation of gonad-inhibiting hormone (GIH), these findings raise the possibility that EcR may influence vitellogenesis through parallel regulatory pathways in the eyestalk and ovary. Transcriptomic analysis of ovaries following EcR suppression identified 3158 differentially expressed genes, including coordinated changes in genes associated with cell-cycle regulation, DNA repair, and chromatin remodeling. Several components of ATP-dependent chromatin remodeling complexes and transcriptional regulators exhibited EcR-dependent expression patterns, which were validated by RT-qPCR. Their stage-specific expression during ovarian development and tissue-specific distribution in reproductive and regulatory organs suggest potential roles in coordinating neuroendocrine networks that integrate hormonal and neural signals to regulate reproduction. Collectively, these findings suggest that EcR influences shrimp vitellogenesis through transcriptional programs linked to chromatin organization and cell-cycle dynamics. Further functional and epigenetic investigations of chromatin-associated regulators may identify targets for non-ablative broodstock management in shrimp aquaculture.