Fagbémi Mohammed Nambyl A, Nivelle Renaud, Muller Marc, Mélard Charles, Lalèyè Philippe, Rougeot Carole
Aquaculture Research and Education Centre (CEFRA), Liège University, query author on which is prefered, 10 Chemin de la Justice B-4500, Tihange, Belgium.
Laboratory of Hydrobiology and Aquaculture (LHA), Faculty of Agricultural Sciences, University of Abomey-Calavi, 01 BP: 526, Cotonou, Benin.
Environ Epigenet. 2024 Jan 13;9(1):dvad009. doi: 10.1093/eep/dvad009. eCollection 2023.
The high temperature sex reversal process leading to functional phenotypic masculinization during development has been widely described in Nile tilapia () under laboratory or aquaculture conditions and in the wild. In this study, we selected five wild populations of from different river basins in Benin and produced twenty full-sib families of mixed-sex (XY and XX) by natural reproduction. Progenies were exposed to room temperature or high (36.5°C) temperatures between 10 and 30 days post-fertilization (dpf). In control groups, we observed sex ratios from 40% to 60% males as expected, except for 3 families from the Gobé region which showed a bias towards males. High temperature treatment significantly increased male rates in each family up to 88%. Transcriptome analysis was performed by RNA-sequencing (RNA-seq) on brains and gonads from control and treated batches of six families at 15 dpf and 40 dpf. Analysis of differentially expressed genes, differentially spliced genes, and correlations with sex reversal was performed. In 40 dpf gonads, genes involved in sex determination such as , and were upregulated. In 15 dpf brains, a negative correlation was found between the expression of and the reversal rate, while at 40 dpf a negative correlation was found between the expression of , and and positive correlation was found between expression and reversal rate. Ontology analysis of the genes affected by high temperatures revealed that male sex differentiation processes, primary male sexual characteristics, autophagy, and cilium organization were affected. Based on these results, we conclude that sex reversal by high temperature treatment leads to similar modifications of the transcriptomes in the gonads and brains in offspring of different natural populations of Nile tilapia, which thus may activate a common cascade of reactions inducing sex reversal in progenies.
在实验室、水产养殖条件及野外环境下，尼罗罗非鱼（）在发育过程中通过高温性逆转过程导致功能性表型雄性化的现象已被广泛描述。在本研究中，我们从贝宁不同流域选取了五个野生尼罗罗非鱼种群，通过自然繁殖产生了20个全同胞混合性别（XY和XX）家系。子代在受精后10至30天（dpf）暴露于室温或高温（36.5°C）环境。在对照组中，除了来自戈贝地区的3个家系显示出雄性偏倚外，我们观察到雄性比例在40%至60%之间，符合预期。高温处理显著提高了每个家系的雄性比例，最高可达88%。在15 dpf和40 dpf时，对来自六个家系的对照和处理批次的脑和性腺进行了RNA测序（RNA-seq）转录组分析。进行了差异表达基因、差异剪接基因分析以及与性逆转的相关性分析。在40 dpf的性腺中，参与性别决定的基因如、和被上调。在15 dpf的脑中，与逆转率之间发现负相关，而在40 dpf时，、和的表达与逆转率之间发现负相关，的表达与逆转率之间发现正相关。对受高温影响的基因进行本体分析表明，雄性性别分化过程、初级雄性性特征、自噬和纤毛组织受到影响。基于这些结果，我们得出结论，高温处理导致的性逆转在尼罗罗非鱼不同自然种群的后代性腺和脑中引起了相似的转录组修饰，从而可能激活了一个共同的反应级联，诱导子代发生性逆转。
