Evaluation of the Ruditapes decussatus immune response after differential injected doses of Perkinsus olseni

Abstract

Ruditapes decussatus is a highly appreciated clam species, with a high demand, especially in European countries. However, natural populations of this species have been affected by over-exploitation, abiotic factors and also by diseases mainly caused by bacteria, virus and protozoans. Within the latter group of pathogens, Perkinsus spp. has been attracting attention for causing relevant mortality rates on bivalves around the world. From all species of this genus, Perkinsus olseni is one of the most impactful for R. decussatus, as it may cause chronic infection with fatal consequences under adverse conditions. Therefore, in this study, naïve clams were injected with two doses of P. olseni in order to better understand the response of R. decussatus against this parasite. So, one of the main goals of this experiment was to evaluate the differential response of the clams at gene expression level after injection and also to monitor the possible mortalities related to parasite. Results indicated that the methods applied for injection and detection of parasite load are effective. Furthermore, altogether, R. decussatus gene expression studies indicate differences on expression of some of the addressed genes among distinct levels of infection over time, which require further studies to confirm if these genes could be used as molecular markers of P. olseni infection. According to the results obtained, Adiponectin-C1q seems to be a promising gene to be used as molecular marker of chronic infection in claḿs haemolymph.

Keywords: Adiponectin; Immune response; Injection; Perkinsus olseni; Ruditapes decussatus.