Ahrens Collin W, Mazanec Richard A, Paap Trudy, Ruthrof Katinka X, Challis Anthea, Hardy Giles, Byrne Margaret, Tissue David T, Rymer Paul D
Hawkesbury Institute for the Environment Western Sydney University Penrith New South Wales Australia.
Biodiversity and Conservation Science, Bentley Delivery Centre Western Australian Department of Biodiversity, Conservation and Attractions Perth Western Australia Australia.
Evol Appl. 2019 Apr 15;12(6):1178-1190. doi: 10.1111/eva.12796. eCollection 2019 Jun.
Natural ecosystems are under pressure from increasing abiotic and biotic stressors, including climate change and novel pathogens, which are putting species at risk of local extinction, and altering community structure, composition and function. Here, we aim to assess adaptive variation in growth and fungal disease resistance within a foundation tree, to determine local adaptation, trait heritability and genetic constraints in adapting to future environments. Two experimental planting sites were established in regions of contrasting rainfall with seed families from 18 populations capturing a wide range of climate origins (~4,000 individuals at each site). Every individual was measured in 2015 and 2016 for growth (height, basal diameter) and disease resistance to a recently introduced leaf blight pathogen (). Narrow-sense heritability was estimated along with trait covariation. Trait variation was regressed against climate-of-origin, and multivariate models were used to develop predictive maps of growth and disease resistance. Growth and blight resistance traits differed significantly among populations, and these differences were consistent between experimental sites and sampling years. Growth and blight resistance were heritable, and comparisons between trait differentiation ( ) and genetic differentiation ( ) revealed that population differences in height and blight resistance traits are due to divergent natural selection. Traits were significantly correlated with climate-of-origin, with cool and wet populations showing the highest levels of growth and blight resistance. These results provide evidence that plants have adaptive growth strategies and pathogen defence strategies. Indeed, the presence of standing genetic variation and trait heritability of growth and blight resistance provide capacity to respond to novel, external pressures. The integration of genetic variation into adaptive management strategies, such as assisted gene migration and seed sourcing, may be used to provide greater resilience for natural ecosystems to both biotic and abiotic stressors.
自然生态系统正面临着日益增加的非生物和生物压力源的压力，包括气候变化和新出现的病原体，这些因素正使物种面临局部灭绝的风险，并改变群落结构、组成和功能。在此，我们旨在评估一种基础树种在生长和真菌病害抗性方面的适应性变异，以确定局部适应性、性状遗传力以及适应未来环境的遗传限制。在降雨情况不同的地区建立了两个实验种植点，使用来自18个种群的种子家系，涵盖了广泛的气候起源（每个种植点约4000株个体）。在2015年和2016年对每一株个体的生长情况（高度、基径）以及对一种最近引入的叶枯病病原体的抗病性进行了测量。估计了狭义遗传力以及性状协方差。将性状变异与起源地气候进行回归分析，并使用多变量模型绘制生长和抗病性的预测图。种群之间的生长和抗叶枯病性状存在显著差异，并且这些差异在实验地点和采样年份之间是一致的。生长和抗叶枯病性状是可遗传的，性状分化（ ）和遗传分化（ ）之间的比较表明，高度和抗叶枯病性状的种群差异是由于自然选择的分歧。性状与起源地气候显著相关，凉爽湿润的种群表现出最高水平的生长和抗叶枯病能力。这些结果提供了证据，表明植物具有适应性生长策略和病原体防御策略。事实上，生长和抗叶枯病性状的现存遗传变异和性状遗传力的存在为应对新的外部压力提供了能力。将遗传变异整合到适应性管理策略中，如辅助基因迁移和种子来源选择，可用于为自然生态系统提供更大的恢复力，以应对生物和非生物压力源。
