Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Daizong Street 61, Tai'an, Shandong, China.
Mar Biotechnol (NY). 2020 Jun;22(3):367-379. doi: 10.1007/s10126-020-09956-5. Epub 2020 Feb 22.
Artificially high temperatures during critical thermosensitive periods (TSPs) can induce the sex reversal of Nile tilapia (Oreochromis niloticus) females into pseudomales; Nile tilapia is a GSD + TE (genotypic plus temperature effects) fish species. Previous studies have shown that water temperature affects the expression levels of many genes in the gonad or brain in various teleost species. However, few studies on the effect of temperature at the whole-gonad transcriptomic level in the early stage of sex differentiation have been reported in fish species exhibiting GSD + TE. In this study, RNA-Seq was performed to characterize the transcriptomic profile and identify genes exhibiting temperature- and sex-biased expressions in the Nile tilapia gonad at 21 dpf. A total of 42 genes were found to be associated with both high-temperature treatment and sex development, as the expression levels of these genes differed in both FC (female control) vs MC (male control) and FC vs FT (high temperature-treated females in the TSP). Among these genes, the transcriptional alterations of many male sex determination and differentiation genes, such as Dmrt1, Gsdf, and the DNA damage-inducible protein GADD45 alpha, suggested that the male pathway is initiated after high-temperature treatment and that its initiation may play a role in high temperature-induced masculinization in Nile tilapia. The qRT-PCR validation results for thirteen differentially expressed genes showed that the Pearson's correlation of the log fold change values between the qPCR and RNA-Seq results was 0.70 (p < 0.001), indicating the accuracy and reliability of the RNA-Seq results. Our study provides insights into how high-temperature treatment induces the sex reversal of Nile tilapia females.
在关键热敏期（TSPs）人为提高温度可诱导尼罗罗非鱼（Oreochromis niloticus）雌鱼性反转为拟雄鱼；尼罗罗非鱼是一种 GSD + TE（基因型加温度效应）鱼类。先前的研究表明，水温会影响各种硬骨鱼类性腺或脑中许多基因的表达水平。然而，在表现 GSD + TE 的鱼类中，关于性分化早期整个性腺转录组水平受温度影响的研究甚少。在这项研究中，我们通过 RNA-Seq 来描述尼罗罗非鱼性腺在 21 日龄时的转录组图谱，并鉴定出在性别分化早期表现出温度和性别偏表达的基因。共有 42 个基因与高温处理和性别发育有关，因为这些基因在 FC（雌鱼对照）与 MC（雄鱼对照）以及 FC 与 FT（TSP 中高温处理的雌鱼）之间的表达水平存在差异。在这些基因中，许多雄性性别决定和分化基因的转录变化，如 Dmrt1、Gsdf 和 DNA 损伤诱导蛋白 GADD45alpha，表明在高温处理后启动了雄性途径，其启动可能在尼罗罗非鱼高温诱导雄性化中发挥作用。13 个差异表达基因的 qRT-PCR 验证结果表明，qPCR 和 RNA-Seq 结果之间的 log 倍变化值的 Pearson 相关系数为 0.70（p<0.001），表明 RNA-Seq 结果的准确性和可靠性。我们的研究为高温处理如何诱导尼罗罗非鱼雌鱼性反转提供了新的见解。
