Transcriptomic response to GnRH down regulation by RNA interference in clam Ruditapes philippinarum, suggest possible role in reproductive function

Gonadotropin-releasing hormone (GnRH) plays a key role in the control of the reproductive axis in vertebrates, however, little is known about its function in reproductive endocrine regulation in molluscs. In the present study, RNA-seq was used to construct transcriptomes of Ruditapes philippinarum testis and ovaries of control and GnRH suppressed individuals using RNA interference. GnRH suppression caused 112 and 169 enriched KEGG pathways in testis and ovary, with 92 pathways in common in both comparisons. The most enriched KEGG pathways occurred in the Oxidative phosphorylation, Dorso-ventral axis formation, Thyroid hormone synthesis and Oxytocin signaling pathway etc. A total of 1838 genes in testis and 358 genes in ovaries were detected differentially expressed in GnRH suppressed clams. Among the differentially expressed genes, a suit of genes related to regulation of steroid hormones synthesis and gonadal development, were found in both ovary and testis with RNAi of GnRH. These results suggest that GnRH may play an important role in reproductive function in bivalves. This study provides a preliminary basis for studying the function and regulatory mechanism of GnRH in bivalves.

Automated summary

GnRH plays a crucial role in reproductive endocrine regulation in molluscs. Suppression of GnRH resulted in enriched KEGG pathways, including oxidative phosphorylation, dorso-ventral axis formation, thyroid hormone synthesis, and oxytocin signaling pathway. Genes related to steroid hormone synthesis and gonadal development were differentially expressed in both ovaries and testes with GnRH suppression. These findings suggest the importance of GnRH in reproductive function in bivalves and provide a basis for further investigating its function and regulatory mechanism.