Octopus minor is an economically important species, but little is known about the histological pattern and regulatory mechanisms during gonadal development. In this study, we investigated the annual changes in total body weight (TW), gonad somatic index (GSI), gonadal histological features, and transcriptome of O. minor. The results indicated that both females and males showed a similar TW trend. The GSI peaked in June in females, while it remained constant at around 3% in males. Nine and four histological stages were observed in ovaries and testes, respectively. Our field sampling results implied that O. minor might have overwintering periods for both eggs and larvae. Transcriptome analysis revealed that a total of 1095 and 2468 genes were significantly expressed during ovarian and testicular development, separately. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis displayed that 126 GO terms and 5 KEGG pathways were significantly enriched in the ovarian group of advanced vitellogenic oocytes vs vitellogenic oocytes (AVO vs VO). The pathways “Ribosomal”, “Cell cycle”, and “Progesterone-mediated oocyte maturation” were predicted to promote yolk deposition. Additionally, the testicular comparison group of spent vs mature (Spent vs Mature) showed significant enrichment in 674 GO terms and 13 KEGG pathways, suggesting that energy metabolism and cell repair pathways may be involved in the spermatogenesis process. This work revealed the development process of the gonads and shed light on the potential regulatory pathways of O. minor, providing novel insights and laying a molecular basis for artificial breeding.

小章鱼是一种重要的经济物种，但人们对性腺发育过程中的组织学模式和调控机制知之甚少。在本研究中，我们调查了小圆线虫总体重（TW）、性腺体细胞指数（GSI）、性腺组织学特征和转录组的年度变化。结果表明，女性和男性都表现出相似的 TW 趋势。女性的 GSI 在 6 月份达到峰值，而男性的 GSI 保持在 3% 左右。在卵巢和睾丸中分别观察到九个和四个组织学阶段。我们的现场采样结果表明，O.minor 的卵和幼虫可能都有越冬期。转录组分析显示，共有 1095 个和 2468 个基因分别在卵巢和睾丸发育过程中显着表达。基因本体论（GO）和京都基因与基因组百科全书（KEGG）富集分析显示，126个GO术语和5个KEGG通路在晚期卵黄卵母细胞与卵黄卵母细胞（AVO vs VO）的卵巢组中显着富集。“核糖体”、“细胞周期”和“黄体酮介导的卵母细胞成熟”途径预计会促进卵黄沉积。此外，废弃与成熟（Spent vs Mature）的睾丸对照组显示出 674 个 GO term 和 13 个 KEGG 通路的显着富集，表明能量代谢和细胞修复通路可能参与精子发生过程。这项工作揭示了O.minor的性腺发育过程，揭示了O.minor的潜在调控途径，为人工育种提供了新的见解并奠定了分子基础。