The role of transcriptome and proteome in developmental competence of eggs of Sander lucioperca

Molecular profiling of the eggs is an excellent approach aiming at understanding biological processes and mechanisms conditioning developmental competence in finfishes and, consequently, reproductive fitness. Despite many efforts, it is still unclear what is the specific role of transcriptome and proteome in determination of egg quality in Teleostei fishes. The aim of this study was to perform integrated transcriptomic-proteomic analysis of eggs of pikeperch – a commercially relevant freshwater fish species. Additionally, comparative analysis of transcriptome and proteome in eggs characterized by either high or low egg quality has been performed, in order to identify mechanisms leading to early embryonic lethality in pikeperch. Our study provides a novel insight into the understanding of the role of maternally-derived molecular cargo in finfishes. The data obtained sheds light on the importance of transcriptome in development of nervous system suggesting neurogenesis-related mRNAs as a very important, non-genetic inheritance factor. Proteomic analysis highlights specific role of proteins in the immune response in ovulated eggs. Integrated analysis brings attention to the galactose-specific lectin nattectin gene and protein as the frontline defense molecule for the egg and developing embryo. The molecular analysis of egg developmental competence emphasizes post-vitellogenic processes (final oocyte maturation and ovulation) as the ones potentially compromising transcriptomic profile, but not affecting proteomic cargo. It highlights the need for careful reconsideration of the commercial reproductive protocols as the very strong modulators of egg quality and their molecular profile. Considering the mechanisms driving these alterations as well as consequences stemming from the differential abundance of the transcripts are still to be explored, the candidate quality markers, first time provided for pikeperch along with the current study, are creating valuable resource for further studies. Comparative analysis of transcriptome in 10 eggs characterized by either high or low egg quality has been performed in pikeperch.