Light is an essential ecological factor that has been demonstrated to affect aquatic animals’ behavior, growth performance, and energy metabolism. Our previous study found that the full-spectrum light and cyan light could promote growth performance and molting frequency of Scylla paramamosain while it was suppressed by violet light. Hence, the purpose of this study is to investigate the underlying molecular mechanism that influences light spectral composition on the growth performance and molting of S. paramamosain. RNA-seq analysis and qPCR were employed to assess the differentially expressed genes (DEGs) of eyestalks from S. paramamosain reared under full-spectrum light (FL), violet light (VL), and cyan light (CL) conditions after 8 weeks trial. The results showed that there are 5024 DEGs in FL vs. VL, 3398 DEGs in FL vs. CL, and 3559 DEGs in VL vs. CL observed. GO analysis showed that the DEGs enriched in the molecular function category involved in chitin binding, structural molecular activity, and structural constituent of cuticle. In addition, the DEGs in FL vs. VL were mainly enriched in the ribosome, amino sugar and nucleotide sugar metabolism, lysosome, apoptosis, and antigen processing and presentation pathways by KEGG pathway analysis. Similarly, ribosome, lysosome, and antigen processing and presentation pathways were major terms that enriched in FL vs. CL group. However, only the ribosome pathway was significantly enriched in up-regulated DEGs in VL vs. CL group. Furthermore, five genes were randomly selected from DEGs for qPCR analysis to validate the RNA-seq data, and the result showed that there was high consistency between the RNA-seq and qPCR. Taken together, violet light exposure may affect the growth performance of S. paramamosain by reducing the ability of immunity and protein biosynthesis, and chitin metabolism.

光是一个重要的生态因素，已被证明会影响水生动物的行为、生长性能和能量代谢。我们前期的研究发现，全光谱光和青色光可以促进拟青青蟹的生长性能和蜕皮频率，而紫光则抑制其生长性能和蜕皮频率。因此，本研究的目的是研究影响光谱组成对S. paramamosain生长性能和蜕皮的潜在分子机制。经过8周的试验后，采用RNA-seq分析和qPCR来评估在全光谱光（FL）、紫光（VL）和青色光（CL）条件下饲养的S. paramamosain眼柄的差异表达基因（DEG） 。结果显示，FL与VL有5024个DEG，FL与CL有3398个DEG，VL与CL有3559个DEG。GO分析表明DEGs富集于涉及几丁质结合、结构分子活性和角质层结构组成的分子功能类别。此外，通过KEGG通路分析发现，FL与VL中的DEG主要富集于核糖体、氨基糖和核苷酸糖代谢、溶酶体、细胞凋亡以及抗原加工和呈递途径。同样，核糖体、溶酶体以及抗原加工和呈递途径是 FL 组与 CL 组中丰富的主要术语。然而，与 CL 组相比，VL 组中只有核糖体途径在上调的 DEG 中显着富集。此外，从DEG中随机选择5个基因进行qPCR分析以验证RNA-seq数据，结果表明RNA-seq与qPCR之间具有较高的一致性。综上所述，紫光照射可能会降低免疫、蛋白质生物合成和几丁质代谢的能力，从而影响副毛沙星的生长性能。