College of Life Sciences, Zhejiang Normal University, Jinhua 321004, China.
Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada.
Int J Mol Sci. 2024 May 29;25(11):5967. doi: 10.3390/ijms25115967.
Extreme weather poses huge challenges for animals that must adapt to wide variations in environmental temperature and, in many cases, it can lead to the local extirpation of populations or even the extinction of an entire species. Previous studies have found that one element of amphibian adaptation to environmental stress involves changes in mitochondrial gene expression at low temperatures. However, to date, comparative studies of gene expression in organisms living at extreme temperatures have focused mainly on nuclear genes. This study sequenced the complete mitochondrial genomes of five Asian hylid frog species: , , , and . It compared the phylogenetic relationships within the Hylidae family and explored the association between mitochondrial gene expression and evolutionary adaptations to cold stress. The present results showed that in , transcript levels of 12 out of 13 mitochondria genes were significantly reduced under cold exposure ( < 0.05); hence, we put forward the conjecture that . adapts by entering a hibernation state at low temperature. In , the transcripts of 10 genes (, , , , , , , , and ) were significantly reduced in response to cold exposure, and five mitochondrial genes in (, , , and ) also showed significantly reduced expression and transcript levels under cold conditions. By contrast, transcript levels of and in . were significantly increased at low temperatures, possibly related to the narrow distribution of this species primarily at low latitudes. Indeed, has little ability to adapt to low temperature (4 °C), or maybe to enter into hibernation, and it shows metabolic disorder in the cold. The present study demonstrates that the regulatory trend of mitochondrial gene expression in amphibians is correlated with their ability to adapt to variable climates in extreme environments. These results can predict which species are more likely to undergo extirpation or extinction with climate change and, thereby, provide new ideas for the study of species extinction in highly variable winter climates.
极端天气给动物带来了巨大的挑战，因为它们必须适应环境温度的广泛变化，在许多情况下，这可能导致局部种群灭绝，甚至整个物种灭绝。先前的研究发现，两栖动物适应环境压力的一个因素涉及到线粒体基因表达在低温下的变化。然而，迄今为止，对生活在极端温度下的生物体的基因表达的比较研究主要集中在核基因上。本研究对五种亚洲树蛙物种的完整线粒体基因组进行了测序： 、 、 、 、 。它比较了树蛙科家族内的系统发育关系，并探讨了线粒体基因表达与对冷应激的进化适应之间的联系。本研究结果表明，在 中，13 个线粒体基因中有 12 个基因的转录水平在低温暴露下显著降低（ < 0.05）；因此，我们提出了 的假设。通过在低温下进入冬眠状态来适应。在 中，10 个基因（ 、 、 、 、 、 、 、 和 ）的转录水平在冷暴露下显著降低，而 中的 5 个线粒体基因（ 、 、 、 和 ）在低温下也表现出显著降低的表达和转录水平。相比之下， 在 中的 和 转录水平在低温下显著升高，可能与该物种主要分布在低纬度有关。事实上， 适应低温（4°C）的能力较弱，或者可能进入冬眠状态，在寒冷中表现出代谢紊乱。本研究表明，两栖动物线粒体基因表达的调控趋势与其在极端环境中适应多变气候的能力相关。这些结果可以预测哪些物种在气候变化中更有可能灭绝，并为高度多变的冬季气候下物种灭绝的研究提供新的思路。
