Giovannini Ilaria, Manfrin Chiara, Greco Samuele, Vincenzi Joel, Altiero Tiziana, Guidetti Roberto, Giulianini Piero, Rebecchi Lorena
Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy.
NBFC, National Biodiversity Future Center, Palermo, Italy.
Front Physiol. 2023 Sep 12;14:1258932. doi: 10.3389/fphys.2023.1258932. eCollection 2023.
The Antarctic region has been experiencing some of the planet's strongest climatic changes, including an expected increase of the land temperature. The potential effects of this warming trend will lead ecosystems to a risk of losing biodiversity. Antarctic mosses and lichens host different microbial groups, micro-arthropods and meiofaunal organisms (e.g., tardigrades, rotifers). The eutardigrade is considered a model animal to study the effect of increasing temperature due to global warming on Antarctic terrestrial communities. In this study, life history traits and fitness of this species are analyzed by rearing specimens at two different and increasing temperatures (5°C vs. 15°C). Moreover, the first transcriptome analysis on is performed, exposing adult animals to a gradual increase of temperature (5°C, 10°C, 15°C, and 20°C) to find differentially expressed genes under short- (1 day) and long-term (15 days) heat stress. specimens reared at 5°C live longer (maximum life span: 686 days), reach sexual maturity later, lay more eggs (which hatch in longer time and in lower percentage) compared with animals reared at 15°C. The fitness decreases in animals belonging to the second generation at both rearing temperatures. The short-term heat exposure leads to significant changes at transcriptomic level, with 67 differentially expressed genes. Of these, 23 upregulated genes suggest alterations of mitochondrial activity and oxido-reductive processes, and two intrinsically disordered protein genes confirm their role to cope with heat stress. The long-term exposure induces alterations limited to 14 genes, and only one annotated gene is upregulated in response to both heat stresses. The decline in transcriptomic response after a long-term exposure indicates that the changes observed in the short-term are likely due to an acclimation response. Therefore, could be able to cope with increasing temperature over time, including the future conditions imposed by global climate change.
南极地区一直在经历地球上一些最强烈的气候变化，包括陆地温度预计会上升。这种变暖趋势的潜在影响将使生态系统面临生物多样性丧失的风险。南极苔藓和地衣栖息着不同的微生物群落、微型节肢动物和小型动物（如缓步动物、轮虫）。真缓步动物被认为是一种模式动物，用于研究全球变暖导致的温度升高对南极陆地群落的影响。在这项研究中，通过在两种不同且不断升高的温度（5°C对15°C）下饲养标本，分析了该物种的生活史特征和适应性。此外，对成年动物进行了首次转录组分析，使其逐渐暴露于温度升高（5°C、10°C、15°C和20°C）的环境中，以寻找短期（1天）和长期（15天）热应激下的差异表达基因。与在15°C下饲养的动物相比，在5°C下饲养的标本寿命更长（最大寿命：686天），性成熟较晚，产卵更多（孵化时间更长且孵化率更低）。在两种饲养温度下，第二代动物的适应性均下降。短期热暴露导致转录组水平发生显著变化，有67个差异表达基因。其中，23个上调基因表明线粒体活性和氧化还原过程发生了改变，两个内在无序蛋白基因证实了它们在应对热应激中的作用。长期暴露仅诱导14个基因发生改变，且只有一个注释基因在两种热应激下均上调。长期暴露后转录组反应的下降表明，短期观察到的变化可能是由于适应反应。因此，真缓步动物可能能够随着时间的推移应对温度升高，包括全球气候变化带来的未来状况。
