Sun Yan-Qiang, Zhao Wei, Xu Chao-Qun, Xu Yulan, El-Kassaby Yousry A, De La Torre Amanda R, Mao Jian-Feng
Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China.
Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Southwest Forestry University, Kunming, China.
Front Genet. 2020 Feb 11;10:1405. doi: 10.3389/fgene.2019.01405. eCollection 2019.
Local adaptation, adaptation to specialized niches and environmental clines have been extensively reported for forest trees. Investigation of the adaptive genetic variation is crucial for forest resource management and breeding, especially in the context of global climate change. Here, we utilized a common garden experiments established at high and low elevation sites to assess the differences in growth and survival among populations and between the two common garden sites. The studied traits showed significant variation between the two test sites and among populations, suggesting adaptive divergence. To detect genetic variation related to environment, we captured 103,608 high quality SNPs based on RNA sequencing, and used them to assess the genetic diversity and population structure. We identified 321 outlier SNPs from 131 genes showing significant divergence in allelic frequency between survival populations of two sites. Functional categories associated with adaptation to high elevation were found to be related to flavonoid biosynthesis, response to UV, DNA repair, response to reactive oxygen species, and membrane lipid metabolic process. Further investigation of the outlier genes showed overrepresentation of the flavonoid biosynthesis pathway, suggesting that this pathway may play a key role in adaptation to high elevation environments. The outlier genes identified, and their variants, provide a basic reference for advanced investigations.
林木的局部适应、对特殊生态位和环境渐变群的适应已有大量报道。对适应性遗传变异的研究对于森林资源管理和育种至关重要，尤其是在全球气候变化的背景下。在此，我们利用在高海拔和低海拔地点建立的共同园试验，评估种群之间以及两个共同园地点之间在生长和存活方面的差异。所研究的性状在两个试验地点之间以及种群之间表现出显著差异，表明存在适应性分化。为了检测与环境相关的遗传变异，我们基于RNA测序捕获了103,608个高质量单核苷酸多态性（SNP），并利用它们评估遗传多样性和种群结构。我们从131个基因中鉴定出321个异常SNP，这些基因在两个地点的存活种群之间的等位基因频率存在显著差异。发现与高海拔适应相关的功能类别与类黄酮生物合成、对紫外线的反应、DNA修复、对活性氧的反应以及膜脂代谢过程有关。对异常基因的进一步研究表明类黄酮生物合成途径过度富集，这表明该途径可能在适应高海拔环境中起关键作用。所鉴定的异常基因及其变体为深入研究提供了基本参考。
