PDF(Pubmed)
Abstract：
Migration is one of the most energy-demanding tasks in avian life cycle. Many birds might not have sufficient fuel stores to cover long distances, so they must stop to rest and refuel at stopover sites, especially after the crossing of large ecological barriers. There, birds undergo several behavioral, morphological, and physiological trait adjustments to recover from and prepare for their journey; however, regulation of such processes at the molecular level remains largely unknown. In this study, we used transcriptomic information from the whole blood of migrating garden warblers (Sylvia borin) to identify key regulatory pathways related to adaptations for migration. Birds were temporarily caged during spring migration stopover and then sampled twice at different refueling states (lean vs. fat), reflecting different migratory stages (stopover arrival vs. departure) after the crossing of an extended ecological barrier. Our results show that top expressed genes during migration are involved in important pathways regarding adaptations to migration at high altitudes such as increase of aerobic capacity and angiogenesis. Gene expression profiles largely reflected the two experimental conditions with several enzymes involved in different aspects of metabolic activity being differentially expressed between states providing several candidate genes for future functional studies. Additionally, we identified several hub genes, upregulated in lean birds that could be involved in the extraordinary phenotypic flexibility in organ mass displayed by avian migrants. Finally, our approach provides novel evidence that regulation of water homeostasis may represent a significant adaptive mechanism, allowing birds to conserve water during long-distance flight, mainly through protein catabolism.
摘要：
迁徙是鸟类生命周期中最需要能量的任务之一。许多鸟类可能没有足够的燃料储备来覆盖长途旅行，所以他们必须停下来在中途停留点休息和加油，尤其是在跨越大型生态屏障之后。在那里,鸟类经历了几种行为，形态和生理性状的调整，以恢复和准备他们的旅程，然而，这些过程在分子水平上的调控在很大程度上仍然未知。在这项研究中，我们使用了来自迁徙花园莺（Sylviaborin）全血的转录组信息来确定与迁徙适应相关的关键调节途径。在春季迁徙中途停留期间，将鸟类暂时关在笼子里，然后在不同的加油状态（瘦肉与脂肪）下采样两次，反映了跨越延伸的生态屏障后不同的迁徙阶段(中途到达和离开)。我们的结果表明，迁移过程中最高表达的基因参与了适应高海拔地区迁移的重要途径，例如有氧能力和血管生成的增加。基因表达谱在很大程度上反映了两种实验条件，其中涉及代谢活性不同方面的几种酶在状态之间差异表达，为未来的功能研究提供了几种候选基因。此外,我们确定了几个hub基因，在瘦鸟中上调，这可能与鸟类移民显示的器官质量异常表型灵活性有关。最后,我们的方法提供了新的证据，水稳态的调节可能代表一个重要的适应机制，允许鸟类在长途飞行中节约用水，主要通过蛋白质分解代谢。
