Veilleux Heather D, Donelson Jennifer M, Munday Philip L
ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville QLD 4811, Australia.
School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia.
Conserv Physiol. 2018 Jan 6;6(1):cox077. doi: 10.1093/conphys/cox077. eCollection 2018.
Reproduction in marine fish is generally tightly linked with water temperature. Consequently, when adults are exposed to projected future ocean temperatures, reproductive output of many species declines precipitously. Recent research has shown that in the common reef fish, , step-wise exposure to higher temperatures over two generations (parents: +1.5°C, offspring: +3.0°C) can improve reproductive output in the F2 generation compared to F2 fish that have experienced the same high temperatures over two generations (F1 parents: +3.0°C, F2 offspring: +3.0°C). To investigate how a step-wise increase in temperature between generations improved reproductive capacity, we tested the expression of well-known teleost reproductive genes in the brain and gonads of F2 fish using quantitative reverse transcription PCR and compared it among control (+0.0°C for two generations), developmental (+3.0°C in second generation only), step (+1.5°C in first generation and +3.0°C in second generation), and transgenerational (+3.0°C for two generations) treatments. We found that levels of gonadotropin receptor gene expression ( and ) in the testes were reduced in developmental and transgenerational temperature treatments, but were similar to control levels in the step treatment. This suggests and may be involved in regulating male reproductive capacity in . In addition, lower expression in the brain of females in all temperature treatments compared to control, suggests that expression, which is involved in vitellogenesis, is sensitive to high temperatures. Our results help elucidate key genes that facilitate successful reproduction in reef fishes when they experience a gradual increase in temperature across generations consistent with the trajectory of climate change.
海洋鱼类的繁殖通常与水温紧密相关。因此，当成年鱼暴露在预计的未来海洋温度下时，许多物种的繁殖产量会急剧下降。最近的研究表明，对于常见的珊瑚礁鱼类，与两代都经历相同高温（F1代亲本：+3.0°C，F2代后代：+3.0°C）的F2代鱼相比，在两代中逐步暴露于更高温度（亲本：+1.5°C，后代：+3.0°C）可提高F2代的繁殖产量。为了研究代际间温度的逐步升高如何提高繁殖能力，我们使用定量逆转录PCR检测了F2代鱼大脑和性腺中著名的硬骨鱼繁殖基因的表达，并在对照（两代均为+0.0°C）、发育（仅第二代+3.0°C）、逐步（第一代+1.5°C，第二代+3.0°C）和跨代（两代均为+3.0°C）处理组之间进行了比较。我们发现，在发育和跨代温度处理组中，睾丸中促性腺激素受体基因（ 和 ）的表达水平降低，但在逐步处理组中与对照水平相似。这表明 和 可能参与调节 的雄性繁殖能力。此外，与对照相比，所有温度处理组中雌性大脑中的 表达均较低，这表明参与卵黄发生的 表达对高温敏感。我们的研究结果有助于阐明当珊瑚礁鱼类经历与气候变化轨迹一致的代际间温度逐渐升高时，促进其成功繁殖的关键基因。
