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

针叶树气候变化反应的遗传、塑料和表观遗传变异来源

• 批准号: RGPIN-2015-04683
• 负责人: Aitken, Sally
• 金额: $ 2.91万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=613106
• 关键词: Genetic; plastic; epigenetic; sources; variation

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.

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，在许多生态系统中作为基础物种发挥着生态作用，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，这将取决于人口作出反应的自然能力。我的研究小组将探索从核心和边缘种群的常设变异，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，以及体细胞突变对常设变异的贡献的适应性反应的潜力。拟议的项目将解决以下问题。 树木种群能从现存的遗传变异中适应新的气候条件吗？我们将使用新的建模和分析方法来分析为AB和BC的284个黑松种群生成的50 K候选和对照SNP的序列变异的现有数据，并为育空地区和美国的边缘种群生成新数据，以预测适应能力。我们还将研究积累的遗传变异，近亲繁殖的变化，和等位基因冲浪在殖民化过程中，通过分析年龄组的锡特卡云杉（云杉）在阿拉斯加的前沿迁移。 亲代环境的表观遗传效应是否有助于它们的后代适应新的气候条件？我们将表型12岁的室内云杉常见的花园包含大量的后代从80个控制交配的相同的父母克隆和种植在两个截然不同的环境：弗农，公元前（年平均温度7.5摄氏度）和王子乔治（4.3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？我们将使用温度，湿度和光周期的控制环境室的处理，以研究的可塑性的锡特卡云杉（Picea sitchensis）幼苗表型，重点是物候和机制确定与不确定（塑料）的初级生长。 体细胞突变是否对适应新环境的持续变异有实质性贡献？在大树的种子萌发和种子生产之间发生的大量有丝分裂细胞分裂可能导致其树冠中的遗传嵌合体，其中一些变异可能有助于适应潜力或造成有害影响，但对于针叶树的体细胞突变率没有很好的估计。在与卑诗省大树攀爬者合作的基础上，我们将对卑诗省一些最大的锡特卡云杉树冠中的许多基因进行采样和测序，以估计突变率。