LAUSR

Abstract The scallop Argopecten purpuratus is a species of importance for aquaculture in Chile and Peru, but in recent years, they have decreased their growth rates and experienced massive mortalities potentially associated with pathogenic infections. Characterization of proteins involved in the immunity status of A. purpuratus is of interest to develop molecular markers to support its culture. Here we report the characterization of a new Peroxiredoxin (Prx) homologue, the first one identified in A. purpuratus. Prxs are a ubiquitous family of cysteine-dependent peroxidase enzymes that play a dominant role in the regulation of peroxide levels in cells, as rapidly detoxify peroxynitrite, hydrogen peroxide and organic hydroperoxides. The molecular and phylogenetic analyses of this gene showed that it is a new member of the PrxV family, thus, it was designated as ApPrxV. This gene showed to be constitutively expressed in each examined tissue, but at a higher level in the striated adductor muscle. ApPrxV expression was highly upregulated in haemocytes in response to an immune challenge with pathogen bacteria Vibrio splendidus. Overall results indicate that ApPrxV is a constitutive and inducible protein that can play an important role in the immune response of A. purpuratus against bacterial infection. Therefore, the results of this study can (i) provide the bases for future functional studies to assess the health status of A. purpuratus; and (ii) can guide the development of molecular markers for future selective breeding of this bivalve.