青藏高原裂腹鱼血细胞的分子发育与适应机制研究

The molecular mechanisms underpinning hypoxia and cold adaptation is a fundamental question in biology, and is also important for aquaculture. The teleost subfamily schizothoracinae diverged in the phased uplifting of the Tibetan Plateau is the dominant fish fauna in the poorly oxygenated and cold waters of the environments, providing an excellent system to study the molecular mechanisms of hypoxia and cold adaptation. Compared to the low altitude, primitive schizothoracinae, both high- and sub-high altitudes schizothoracines demonstrated elevated dN/dS ratios in genes involved in blood circulation, immunity and metabolic processes. It suggested that hematopoietic adaptation is a crucial aspect of adaptation to the hypoxia and cold environments in the Tibetan Plateau schizothoracines. In this project, we will compare blood parameters of different grades of specialized schizothoracines, link specific traits of blood cells of the high plateau adaptation with the molecular developmental mechanism, and unfold the key signal pathways and regulatory mechanisms underlying the hypoxia and cold adaptation. We will also use the cold-adapted Antarctic notothenioids to compare with the Tibetan fishes to reveal the differences in hematopoiesis which adapted to either a constantly cold environment (Antarctic) or an environment with both hypoxia and cold stresses, thus unfold the correlations between the long-term hypoxia adaptation and long-term cold adaptation in hematopoiesis. In summary, we aim to illuminate the molecular nature of hypoxia and cold adaptations of hematopoiesis, and provide theoretical bases for improving the hypoxia and cold resistance traits in breeding of aquaculture varieties.

水生生物对低氧、低温适应的机制是生物学基础问题，对水产养殖具有重要意义。裂腹鱼亚科鱼类伴随着青藏高原的隆升，在低氧、低温的环境压力下逐渐分化，成为多特化等级的高原鱼类，是研究低氧、低温适应机制的极佳体系。前期工作发现，与低海拔的原始裂腹鱼相比，特化的高海拔高原裂腹鱼在血液生成、免疫反应、代谢等生物过程的进化速度明显加快，其血细胞的分子发育是适应该极端环境的重要方面。本项目从比较不同特化等级裂腹鱼的血细胞发育过程出发，把适应高原极端环境的血细胞生理性状与分子发育机制紧密结合起来，挖掘其关键信号通路与调控机制，并与极端低温环境压力下的南极亚目鱼类血细胞发生的适应机制相比较，揭示血细胞发生的长期低温与低氧适应的相关性，从而阐明鱼类血细胞发生耐低氧、耐低温的分子生物学本质。本项目研究结果可为水产养殖的耐低氧、耐低温的良种培育提供理论依据。

裂腹鱼亚科鱼类伴随着青藏高原的隆升，在低氧、低温的环境压力下逐渐分化，成为多特化等级的高原鱼类，是研究低氧、低温适应机制的极佳体系。本课题以不同特化等级的裂腹鱼为研究对象，比较研究了多个高原裂腹鱼的血液学指标与特征，揭示了不同特化等级裂腹鱼血细胞的形态差异与发育过程差异。对不同特化等级裂腹鱼血液发生相关组织进行转录组比较，揭示了高原裂腹鱼血细胞发生相关的重要基因及信号通路。与极端低温环境下南极亚目鱼类血细胞发生的适应机制相比较，揭示高原裂腹鱼长期低温低氧下的血细胞发生与南极鱼类的长期极端低温下血细胞发生的分子适应机制的差异。利用长期低氧驯化的斑马鱼重演低氧对鱼类血液细胞发生造成的影响，阐释鱼类血细胞发生耐低氧的分子生物学本质。获得了几个低氧条件下影响鱼类心血管发生的关键基因的功能，筛选出一批与低氧适应相关的功能基因，为养殖鱼类的低氧育种指出了新的方向。