Table4_Expression Regulation Mechanisms of Sea Urchin (Strongylocentrotus intermedius) Under the High Temperature: New Evidence for the miRNA-mRNA Interaction Involvement.DOCX

In the context of global warming and continuous high temperatures in the northern part of China during summer, the mortality rate of our main breeding species, Strongylocentrotus intermedius, reached 80% in 2020. How sea urchins respond to high temperatures is of great concern to academia and industry. In this study, we examined the antioxidant enzyme activities of different color tube-footed sea urchins under heat stress and compared their transcriptome and microRNA (miRNA) profiles using RNA-Seq. The results showed that the antioxidant enzyme activities of sea urchins were altered by thermal stress, and the changes in peroxidase activities of red tube-footed sea urchins were particularly significant. Investigations revealed that 1,079 differentially expressed genes (DEGs), 11 DE miRNAs, and 104 “DE miRNA-DEG” pairs in total were detected in sea urchins under high temperature stress. Several mRNA and miRNAs were significantly changed (e.g. HSP70, DnaJ11, HYAL, CALR, miR-184-p5, miR-92a, miR-92c, and miR-124-p5), suggesting these genes and miRNAs exerted important functions in response to high temperature. At the transcriptional level, red tube-footed sea urchins were found to be more sensitive to high temperature and could respond to high temperature rapidly. DE miRNA-mRNA network showed that miR-92b-3p and PC-5p-7420 were the most corresponding miRNAs. Five mRNAs (DnaJ11, SAR1B, CALR, HYOU1, TUBA) may be potential markers of sea urchin response to high temperature. Possible interaction between miRNA-mRNA could be linked to protein folding in the endoplasmic reticulum, Phagosomes, and calcium transport. This study provides a theoretical basis for the molecular mechanism of sea urchin heat tolerance and information that will aid in the selection and breeding of sea urchins with high temperature tolerance.

在全球变暖背景下，中国北方夏季持续出现高温天气，2020年我们的主要养殖物种中间球海胆（Strongylocentrotus intermedius）的死亡率高达80%。海胆对高温的响应机制是学界与产业界共同关注的重要课题。本研究针对不同管足颜色的海胆，检测其在热应激条件下的抗氧化酶活性，并通过RNA测序（RNA-Seq）比较各组的转录组与微小RNA（microRNA, miRNA）表达谱。研究结果显示，热应激会改变海胆的抗氧化酶活性，其中红色管足海胆的过氧化物酶活性变化最为显著。经检测，高温应激下海胆中共鉴定出1079个差异表达基因（differentially expressed genes, DEGs）、11个差异表达miRNA（DE miRNAs）以及104对"DE miRNA-DEG"调控组合。多个mRNA与miRNA的表达量发生显著变化（如HSP70、DnaJ11、HYAL、CALR、miR-184-p5、miR-92a、miR-92c及miR-124-p5），提示这些基因与miRNA在海胆应对高温胁迫的过程中发挥了关键调控功能。转录组层面的分析表明，红色管足海胆对高温胁迫更为敏感，能够快速启动高温响应机制。差异表达miRNA-mRNA调控网络分析显示，miR-92b-3p与PC-5p-7420是关联靶基因最多的miRNA。另有5个mRNA（DnaJ11、SAR1B、CALR、HYOU1、TUBA）或可作为海胆响应高温胁迫的潜在分子标志物。miRNA与mRNA的潜在互作通路可能涉及内质网蛋白质折叠、吞噬体功能以及钙离子转运过程。本研究为解析海胆耐热性的分子调控机制提供了理论依据，同时也为耐高温海胆的选育工作提供了重要参考信息。