Department of Biology, Centre for Biomedical Research, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia, V8W 3N5, Canada.
Mol Ecol. 2014 Apr;23(8):1952-64. doi: 10.1111/mec.12713. Epub 2014 Apr 5.
Divergent life history strategies occur in steelhead or rainbow trout Oncorhynchus mykiss, and many populations produce both migrant (anadromous fish that move to the ocean after rearing) and resident (do not migrate and remain in fresh water) individuals. Mechanisms leading to each type are only partially understood; while the general tendency of a population is heritable, individual tendency may be plastic, influenced by local environment. Steelhead hatchery programmes aim to mitigate losses in wild stocks by producing trout that will migrate to the ocean and not compete with wild trout for limited freshwater resources. To increase our understanding of gill function in these migratory or resident phenotypes, here we compare gill transcriptome profiles of hatchery-released fish either at the release site (residents) or five river kilometres downstream while still in full fresh water (migrants). To test whether any of these genes can be used as predictive markers for smoltification, we compared these genes between migrant-like and undifferentiated trout while still in the hatchery in a common environment (prerelease). Results confirmed the gradual process of smoltification, and the importance of energetics, gill remodelling and ion transport capacity for migrants. Additionally, residents overexpressed transcripts involved in antiviral defences, potentially for immune surveillance via dendritic cells in the gills. The best smoltification marker candidate was protein s100a4, expression of which was highly correlated with Na(+) , K(+) ATPase (NKA) activity and smolt-like morphology in pre- and postrelease trout gills.
虹鳟或海三文鱼的生活史策略存在分歧，许多种群既产生洄游型（幼鱼在海洋中育肥后洄游）个体，也产生定居型（不洄游，留在淡水中）个体。导致每种类型的机制仅部分被理解；虽然种群的总体趋势是可遗传的，但个体趋势可能是可塑性的，受局部环境的影响。虹鳟养殖场项目旨在通过生产将迁移到海洋的鳟鱼来减轻野生种群的损失，这些鳟鱼不会与野生鳟鱼争夺有限的淡水资源。为了增加我们对这些洄游或定居表型中鳃功能的理解，我们比较了在释放地点（定居者）或仍在全淡水下游五公里处（洄游者）释放的养殖场释放的鱼的鳃转录组图谱。为了测试这些基因中的任何一个是否可以用作变态的预测标记，我们在共同环境中（释放前）比较了仍在养殖场中的洄游型和未分化鳟鱼之间的这些基因。结果证实了变态的渐进过程，以及能量学、鳃重塑和离子转运能力对洄游者的重要性。此外，定居者过度表达了与抗病毒防御相关的转录本，这可能是通过鳃中的树突状细胞进行免疫监视。最好的变态标记候选物是蛋白 s100a4，其表达与 Na(+) 、K(+) ATPase (NKA) 活性和预释放和释放后鳟鱼鳃的变态样形态高度相关。
