Genetic, plastic and epigenetic sources of variation for climate change responses in conifers

针叶树种群适应新气候条件的能力很重要，因为它们在全球碳循环中发挥着重要作用，在许多生态系统中扮演着基础物种的生态角色，对资源生产也很重要。考虑到气候变化，我们应该在多大程度上改变森林养护和管理战略，将取决于人口的自然应对能力。我的研究小组将探索核心和边缘种群的立地变异、对亲本环境的表观遗传反应、通过表型可塑性对新条件的耐受性以及体细胞突变对立地变异的贡献的适应反应的可能性。拟议的项目将解决以下问题。*树木种群能否通过现有的遗传变异来适应新的气候条件？我们将使用新的建模和分析方法来分析现有的50K候选和控制AB和BC的284个种群的SNPs序列变异数据，并为育空和美国的边缘种群生成新的数据来预测适应能力。我们还将通过分析阿拉斯加迁徙前沿的锡特卡云杉(Picea Sitchens)的年龄队列，研究在殖民过程中遗传变异的积累、近亲繁殖的变化和等位基因冲浪。*亲代环境的表观遗传效应是否有助于他们的后代适应新的气候条件？我们将对12年生的室内云杉普通花园进行表型，其中包含来自相同亲本的80个受控交配的大量后代，并克隆并种植在两个截然不同的环境中：不列颠哥伦比亚省弗农(年平均气温7.5摄氏度)和乔治王子(4.3C摄氏度)。如果检测到表型效应，我们将对与表观遗传效应相关联的标记进行全基因组关联作图。*表型可塑性是否足以使树木调整其生长和休眠周期，以与新的气候条件同步？我们将利用受控环境箱中的温度、水分和光周期处理来研究锡特卡云杉(Picea Sitchensis)幼苗表型的可塑性，重点是物候学和确定与不确定(塑料)初级生长的机制。*体细胞突变对适应新条件的站立变化有实质性贡献吗？大树在种子萌发和种子产生之间发生的大量有丝分裂细胞分裂可以导致树冠的遗传嵌合体，其中一些变异可能有助于适应潜力或造成有害影响，但对针叶树的体细胞突变率没有很好的估计。在与不列颠哥伦比亚省的大树攀登者合作的基础上，我们将对不列颠哥伦比亚省一些最大的锡特卡云杉的树冠中的许多基因进行采样和测序，以估计突变率。

The capacity of conifer populations to adapt to new climatic conditions is important because of their large roles in the global carbon cycle, ecological roles as foundation species in many ecosystems, and importance for resource production. The extent to which we should change forest conservation and management strategies in consideration of climate change will depend on the natural capacity of populations to respond. My research group will explore the potential for adaptive responses from standing variation in core and marginal populations, epigenetic responses to parental environments, tolerance of new conditions through phenotypic plasticity, and contributions to standing variation from somatic mutations. The proposed projects will address the following questions. ***Can tree populations adapt to new climatic conditions from standing genetic variation? We will use new modelling and analytical approaches to analyze existing data on sequence variation in 50K candidate and control SNPs generated for 284 populations of lodgepole pine in AB and BC, and generate new data for marginal populations in Yukon and the US to predict capacity for adaptation. We will also study accumulation of genetic variation, changes in inbreeding, and allele surfing during colonization by analyzing age cohorts of Sitka spruce (Picea sitchensis) at the leading edge of migration in Alaska.***Will epigenetic effects of parental environments help adapt their progeny to new climatic conditions? We will phenotype 12-year-old interior spruce common gardens containing a large number of progeny from 80 controlled matings of the same parents cloned and planted in two contrasting environments: Vernon, BC (mean annual temperature 7.5C) and Prince George (4.3C). If phenotypic effects are detected, we will conduct genome-wide association mapping of markers linked to epigenetic effects.***Is phenotypic plasticity sufficient to allow trees to adjust their growth and dormancy cycles to synchronize with new climatic conditions? We will use temperature, moisture and photoperiodic treatments in controlled environment chambers to study the plasticity of Sitka spruce (Picea sitchensis) seedling phenotypes, with an emphasis on phenology and mechanisms of determinate versus indeterminate (plastic) primary growth.***Do somatic mutations contribute substantively to standing variation for adaptation to new conditions? The large number of mitotic cell divisions that occur between seed germination and seed production in large trees can result in genetic mosaicism in their crowns, and some of that variation may contribute to adaptive potential or cause deleterious effects, but no good estimates exist for somatic mutation rates in conifers. Building on a partnership with big tree climbers in BC, we will sample and sequence many genes in the crowns of some of BC's largest Sitka spruce to estimate mutation rates.**