Pearlscale angelfish Centropyge vrolikii is a kind of protogynous hermaphrodite fish with a natural sexual reversion. Under appropriate social conditions, a female fish can transform into a male fish spontaneously. It is an important prerequisite for artificial breeding to understand the process of its gonadal development and sexual reversion. Gonadal development is regulated by many sex-related genes. In this study, we used unreferenced RNA-Seq technology to sequence the ovary at the perinucleolus stage (O_II), ovary at the yolk vesicle stage (O_IV),IV and testis (T), respectively; screened the gonadal differential expression genes (DEGs); and analyzed the expression of these genes in different developmental stages of ovary and different sex gonads. The results showed that a total of 142,589 all-unigene samples were assembled, and gene annotation was performed by COG, GO, KEGG, KOG, Pfam, Swissprot, eggNOG, and NR functional database. Comparative analysis revealed that there were 1919 genes that were up-regulated and 1289 genes were down-regulated in comparison to O_IV vs O_II, while there were 3653 genes that were up-regulated and 2874 genes were down-regulated in comparison of O_IV vs T, there were 3345 genes that were up-regulated and 2995 genes were down-regulated in comparison of the O_II vs the T. At the same time, the results verified by RT-qPCR were consistent with the variation trend of transcriptome data. Among the results, amh, sox9b, dmrt1, dmrt2, cyp11a, cyp17a, and cyp19a were significantly expressed in the testes, while sox3, sox4, sox11, sox17, and hsd3b7 were significantly expressed in the ovaries. And, the expression of the amh, sox9b, dmrt2, and dmrt1 were low in the O_II and O_IV, while significantly increased during the ovotestis in the hermaphroditic period (O_T), and finally reached the highest level in pure testis after sex reversal. The expression of sox3, sox4, hsd3b7, sox11, and sox17 was significantly reduced during the hermaphroditic period (O_T). These results suggested that these genes may play an important role in the process of sex reversal. This study is helpful to further understand the molecular regulation mechanism of gonadal development and sexual reversion in Pearlscale angelfish and also provide important clues for future studies.

珍珠鳞神仙鱼Centropyge vrolikii是一种具有自然性反转的雌雄同体的原始鱼。在适当的社会条件下，雌鱼可以自发地转变为雄鱼。了解其性腺发育和性逆转的过程是人工育种的重要前提。性腺发育受许多性相关基因的调控。在本研究中，我们使用未参考的 RNA-Seq 技术对处于核周阶段 (O _II ) 的卵巢、处于卵黄囊泡阶段 (O _IV),IV 和睾丸 (T)，分别；筛选性腺差异表达基因（DEGs）；并分析了这些基因在卵巢不同发育阶段和不同性腺的表达情况。结果表明，共组装了142,589个all-unigene样本，并通过COG、GO、KEGG、KOG、Pfam、Swissprot、eggNOG、NR功能数据库进行基因注释。比较分析显示，与O _IV vs O _II相比，上调基因1919个，下调基因1289个，而与O相比，上调基因3653个，下调基因2874个。_IV vs T，与O _II相比，有3345个基因上调，2995个基因下调同时，RT-qPCR验证的结果与转录组数据的变化趋势一致。结果中，amh、sox9b、dmrt1、dmrt2、cyp11a、cyp17a和cyp19a在睾丸中显着表达，而sox3、sox4、sox11、sox17和hsd3b7在卵巢中显着表达。并且，amh、sox9b、dmrt2和dmrt1在 O _{II 中}的表达较低和O _IV，而在雌雄同体期（O _T）的卵睾期间显着增加，最终在性逆转后在纯睾丸中达到最高水平。的表达SOX3，SOX4，hsd3b7，的Sox11，和SOX17在雌雄同体期间（O物显著降低_Ť）。这些结果表明这些基因可能在性别逆转过程中发挥重要作用。本研究有助于进一步了解珍珠鳞神仙鱼性腺发育和性逆转的分子调控机制，也为今后的研究提供重要线索。