Local adaptation of Nothofagus pumilio along the latitudinal gradient of the Andes

由于人为气候变化导致的压力事件和压力事件的增加，适应潜力程度的研究是进化森林生态学中一个重要而活跃的研究领域。然而，这一研究领域的成功总体上仍然受到相当有限的基因组资源、缺乏小尺度环境信息以及在其自然种群中对表型树的巨大挑战的阻碍。在这个项目中，我们利用1)安第斯山脉的纬度和地形梯度提供的独特机会来研究与光和气候相关的局部适应途径，以及2)在H2020 GenTree项目框架下为7种欧洲树种创建的基因组和表型资源。本研究的目的是：(1)确定具有重要生态和经济意义的巴塔哥尼亚树种Nothofagus pumilio的局部适应的遗传和表型基础；(2)确定人口统计学历史、自然选择、基因流和主要环境驱动因素影响遗传多样性和局部适应的空间尺度；(3)检验南部山毛榉和欧洲树种之间的局部适应是否趋同进化。为此，我们将把来自相关途径的约1000个候选基因的遗传变异与来自树木年轮数据的表型（树轮表型）联系起来，以量化个体和种群对安第斯山脉纬度和气候东西梯度的环境差异的基因组反应。此外，利用树木表型，我们将研究树木对与这些梯度无关的胁迫事件的反应，即与ENSO相关的气候变异和虫害暴发。同时，我们将使用中性遗传标记在关联研究中考虑种群的人口统计学历史，并确定基因流动距离。最后，我们试图调查来自巴塔哥尼亚和欧洲的树种是否收敛地适应了所调查的选择压力。为此，我们将把我们的结果与目前正在进行的在7种欧洲树种中进行的相同实验设计的研究进行比较。这些物种包括亲缘关系相对较近的山毛榉（Fagus sylvatica）和栎树（Quercus robur），以及亲缘关系非常远的针叶树云杉（Picea abies）。除了更好地了解关键途径中地方适应的遗传基础外，确定遗传多样性、基因流动和地方适应的规模将有助于森林工作者实施更有针对性的森林遗传资源管理战略。例如，我们的结果可以转化为鉴定黑穗病菌的种源带。

In the light of increasing stress events and stress episodes due to anthropogenic climate change the investigation of the extent of adaptive potential is a crucial and vibrant research field in evolutionary forest ecology. However, the success of this research field in general is still hampered by rather limited genomic resources, by the lack of small-scale environmental information, and by the huge challenge to phenotype trees in their natural populations.In this project, we take advantage of i) the unique opportunity that the Andean latitudinal and orographic gradients offer to study local adaptation in pathways related to light and climate, and ii) the genomic and phenotypic resources created for seven European tree species in the framework of the H2020 GenTree project.The goals of this study are i) to identify the genetic and phenotypic basis of local adaptation in the ecologically and economically important Patagonian tree species Nothofagus pumilio, ii) to determine the spatial scale at which demographic history, natural selection, gene flow, and major environmental drivers shape genetic diversity and local adaptation, and iii) to test whether local adaptation evolved convergently among Southern beech and European tree species.For these purposes, we will link genetic variation in a set of ~1,000 candidate genes from relevant pathways with phenotypes derived from tree ring data (dendrophenotypes) to quantify the genomic response of individuals and populations to environmental differences along the latitudinal and the climatic east-west gradient of the Andes. In addition, using dendrophenotypes, we will investigate the response of trees to stress events unlinked to these gradients, namely ENSO related climatic variability and pest outbreaks. In parallel, we will use neutral genetic markers to take the demographic history of populations into account in association studies, and to determine gene flow distances. Finally, we seek to investigate whether tree species from Patagonia and Europe adapted convergently to the investigated selective pressures. For this, we will compare our results with currently ongoing studies of identical experimental design conducted in seven European tree species. These include the relatively closely related Fagus sylvatica and Quercus robur as well as the very distantly related conifer Picea abies. Aside from a better understanding of the genetic foundation of local adaptation in essential pathways, identifying the scale of genetic diversity, gene flow and local adaptation will help inform foresters to implement more targeted management strategies of forest genetic resources. For example, our results can be translated into the identification of provenance zones for N. pumilio.