Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research of the Amazon, André Araújo Avenue, 2936, 69067-375, Petrópolis, Manaus, AM, Brazil.
Computational Systems Biology Laboratory, University of São Paulo, Professor Lúcio Martins Rodrigues Avenue, 370, 05508020, Butantã, São Paulo, SP, Brazil.
J Therm Biol. 2020 Apr;89:102487. doi: 10.1016/j.jtherbio.2019.102487. Epub 2020 Mar 13.
Tambaqui (Colossoma macropomum Cuvier, 1818) is an endemic fish of the Amazon and Orinoco basins, and it is the most economically important native species in Brazil being raised in five climatically distinct regions. In the face of current global warming, environmental variations in farm ponds represent additional challenges that may drive new adaptive regional genetic variations among broodstocks of tambaqui. In an experimental context based on the high-emission scenario of the 5th Intergovernmental Panel on Climate Change (IPCC) report, we used two farmed tambaqui populations to test this hypothesis. RNA-seq transcriptome analysis was performed in the liver of juvenile tambaqui from northern (Balbina Experimental Station, Balbina, AM) and southeastern (Brumado Fish Farming, Mogi Mirim, SP) Brazilian regions kept for 30 days in artificial environmental rooms mimicking the current and extreme climate scenarios. Three Illumina MiSeq runs produced close to 120 million 500 bp paired-end reads; 191,139 contigs were assembled with N50 = 1595. 355 genes were differentially expressed for both populations in response to the extreme scenario. After enrichment analysis, each population presented a core set of genes to cope with climate change. Northern fish induced genes related to the cellular response to stress, activation of MAPK activity, response to unfolded protein, protein metabolism and cellular response to DNA damage stimuli. Genes biologically involved in regulating cell proliferation, protein stabilisation and protein ubiquitination for degradation through the ubiquitin-proteasome system were downregulated. Genes associated with biological processes, including the cellular response to stress, MAPK cascade activation, homeostatic processes and positive regulation of immune responses were upregulated in southeastern fish. The downregulated genes were related to cytoskeleton organisation, energy metabolism, and the regulation of transcription and biological rhythms. Our findings reveal the signatures of promising candidate genes involved in the regional plasticity of each population of tambaqui in dealing with upcoming climate changes.
巨臀脂鲤（Colossoma macropomum Cuvier, 1818）是亚马逊和奥里诺科盆地的特有鱼类，是巴西经济上最重要的本地物种，在五个气候截然不同的地区进行养殖。面对当前的全球变暖，养殖池塘的环境变化代表了新的适应区域性遗传变异的额外挑战，这些变异可能会影响巨臀脂鲤的亲鱼。在基于政府间气候变化专门委员会（IPCC）第五次报告的高排放情景的实验背景下，我们使用了两个养殖的巨臀脂鲤种群来检验这一假设。对来自巴西北部（巴尔比纳实验站，巴尔比纳，AM）和东南部（布鲁马迪诺养鱼场，莫吉米林，SP）的幼年巨臀脂鲤肝脏进行了 RNA-seq 转录组分析，这些鱼在人工环境室中饲养了 30 天，这些环境室模拟了当前和极端气候情景。三次 Illumina MiSeq 运行产生了近 1.2 亿个 500bp 配对末端读取；组装出了 191139 个 contigs，N50 = 1595.355。对于两个种群，由于极端情况的影响，有 355 个基因表现出差异表达。经过富集分析，每个种群都有一组核心基因来应对气候变化。北方鱼类诱导的基因与细胞对压力的反应、MAPK 活性的激活、对未折叠蛋白的反应、蛋白质代谢和细胞对 DNA 损伤刺激的反应有关。生物上涉及调节细胞增殖、蛋白质稳定和通过泛素-蛋白酶体系统进行降解的蛋白质泛素化的基因被下调。与生物过程相关的基因，包括细胞对压力的反应、MAPK 级联激活、稳态过程和免疫反应的正向调节，在东南鱼类中上调。下调的基因与细胞骨架组织、能量代谢以及转录和生物节律的调节有关。我们的研究结果揭示了巨臀脂鲤每个种群在应对未来气候变化时参与区域可塑性的有希望的候选基因的特征。
