“Testicular beta-defensin transcriptional profile in European sea bass (7077)” Written by marina02 on August 21, 2025. Posted in Abstracts. Abstract TESTICULAR BETA-DEFENSIN TRANSCRIPTIONAL PROFILE IN EUROPEAN SEA BASS TESTICULAR BETA-DEFENSIN TRANSCRIPTIONAL PROFILE IN EUROPEAN SEA BASS Laura Cervera1,2, Yulema Valero1,2, Alberto Cuesta2, Marta Arizcun1, Elena Chaves-Pozo1* 1 Centro Oceanográfico de Murcia (COMU-IEO), CSIC, Spain *elena.chaves@ieo.csic.es 2 University of Murcia, Spain Introduction Antimicrobial peptides (AMPs) are small peptides with immunomodulatory properties and direct lytic effects on a wide range of pathogens. Among AMPs, beta-defensins (Bdef) are characterized by the presence of conserved cysteines and three disulfide bonds. In certain species mammals or teleost species, the presence of Bdef in the reproductive tract have been reported especially in males. Their presence is key for fighting against certain pathogens which affects gonadal tissues such as betanodavirus (NNV). NNV can reach the gonad and cause a persistence infection which can be transmitted to the highly susceptible progeny. In this context, our project focuses on the role of Bdef in testes via molecular characterization. Methodology Testes and ovaries from broodstock of European sea bass were collected at the gametogenesis stage. Testes of healthy specimens were also sampled monthly to study Bdefs coding gene expression during the male reproductive cycle An in vivo infection was performed by injecting male specimens with culture medium alone or containing 106 TCID50 of RGNNV/fish. Testes were removed after 1-, 7- and 15-days post-infection (dpi). All samples were processed for gene expression analysis using qPCR. Results The expression levels of bdef1 were similar in testis and ovary while bdef2 expression was higher in testis. Besides, the transcriptional levels of bdef2 were higher than bdef1 in testis. During the male reproductive cycle, the highest expression of bdef1 occurred during spermatogenesis stage while bdef2 was more expressed in spawning stage. During NNV in vivo infection bdef1 was up-regulated at 7 dpi while bdef2 remained unaltered. Conclusions Bdef2 seems to be preferentially expressed in the male reproductive tract. Otherwise, bdef1 and bdef2 might have different functionalities in testes since their expression reach their peak at different stages. The pattern of expression of bdef1 is similar to other AMPs in testis upon NNV infection pointing to the antiviral role of bdef1. More efforts are needed to clarify differences in regulation of both transcripts. Funding This research was funded by the European Union NextGenerationEU/PRTR, MCIN/AEI10.13039/501100011033 and Fundación Séneca (ThinkInAzulprogramme: PRTR-C17.I1), by MCIN/AEI/10.13039/501100011033 grant PRE2020-093771 to L.C. and by MICIU/AEI/10.13039/501100011033 and the European Union NextGenerationEU/PRTR to Y.V. Acknowledgements We would like to thank to the technical staff of the Aquaculture facilities of the COMU-IEO, CSIC. Authors CHAVES-POZO, ELENA, COMU-IEO, CSIC, Presenter Cervera, Laura, University of Murcia, Author Yulema, Valero, University of Murcia, Author Cuesta, Alberto, University of Murcia, Author Arizcun, Marta, COMU-IEO, CSIC, Author Previous Next