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Transcriptomes reveal the involved genes in the sea urchin Mesocentrotus nudus exposed to high flow velocities

Despite the importance of flow velocity in marine ecosystems, molecular mechanisms of the water flow induced behavioral and growth changes remain largely unknown in sea urchins. The present study compared the gene expressions of the sea urchin Mesocentrotus nudus at high flow velocities (10 cm/s and 20 cm/s) and low flow velocity (2 cm/s) using transcriptomes. A total of 490 and 470 differentially expressed genes (DEGs) were discovered at 10 cm/s and 20 cm/s, respectively. There were 235 up-regulated and 255 down-regulated genes at 10 cm/s, 213 up-regulated and 257 down-regulated genes at 20 cm/s, compared with sea urchins at 2 cm/s. Further, there were 72 overlapped DEGs involved in regulation at both 10 cm/s and 20 cm/s. Gene Ontology (GO) functional annotation showed that DEGs were mainly enriched to cellular process, cell part, binding, and metabolism process. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis found that DEGs were enriched in three pathways related to amino acid metabolism and lipid metabolism. A number of genes related to growth and metabolism of sea urchins were mobilized in high flow velocity environment. We further highlighted a muscle-associated gene ankyrin-1, which is correlated with the movement of tube feet at different flow velocities. The present study provides valuable information on the molecular mechanisms of changed behaviors and growth when sea urchins are exposed to high flow velocity.