Intraspecific hybridization as a mitigation strategy of ocean acidification in marine bivalve noble scallop Chlamys nobilis

bivalves. Hybridization is one of the important methods to improve environmental tolerance of animals and plants. In this study, we explored the feasibility of intraspecific hybridization as an OA mitigation strategy in noble scallop Chlamys nobilis (ecologically and economically important bivalve species). The results of this study revealed that exposure of C. nobilis to OA condition significantly reduced the hatching rate, survival rate, growth rate (shell height, shell length, shell width and shell weight), and total carotenoid content (TCC), as well as increased the deformity rate of C. nobilis larvae. Interestingly, under both ambient water and OA condition, the intraspecific hybridization of C. nobilis exhibited heterosis in terms of hatching rate, survival rate and growth rate (excepted for growth in shell length under OA). Transcriptome sequencing of C. nobilis (inbreed and hybrid under ambient and OA conditions) identified four main differentially expressed genes involved in signal transduction, biological process maintenances, nucleic acid binding and post-translational modification. In addition, the expression of these four genes in hybrid C. nobilis was significantly higher than that in inbreed C. nobilis. In conclusion, hybrid C. nobilis showed heterosis in growth rate and survival rate under both ambient water and acidified seawater condition, which may be the result of enhanced expression of genes related to signal transduction, DNA replication and post-translational modification.

Automated summary

This study investigated the feasibility of intraspecific hybridization as a strategy to mitigate the negative effects of ocean acidification (OA) on noble scallop Chlamys nobilis. It was found that intraspecific hybridization resulted in heterosis in terms of growth rate and survival rate under both ambient water and acidified seawater conditions. Transcriptome sequencing revealed that the expression of genes involved in signal transduction, biological process maintenance, nucleic acid binding, and post-translational modification was significantly higher in hybrid C. nobilis compared to inbreed C. nobilis.