拟南芥在异质沙丘景观中的生活史特征和热应激性能的遗传分化。
Genetic differentiation in life history traits and thermal stress performance across a heterogeneous dune landscape in Arabidopsis lyrata.
机构信息
Department of Environmental Sciences, University of Basel, Basel, Switzerland.
Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland.
出版信息
Ann Bot. 2018 Aug 27;122(3):473-484. doi: 10.1093/aob/mcy090.
BACKGROUND AND AIMS
Over very short spatial scales, the habitat of a species can differ in multiple abiotic and biotic factors. These factors may impose natural selection on several traits and can cause genetic differentiation within a population. We studied multivariate genetic differentiation in a plant species of a sand dune landscape by linking environmental variation with differences in genotypic trait values and gene expression levels to find traits and candidate genes of microgeographical adaptation.
METHODS
Maternal seed families of Arabidopsis lyrata were collected in Saugatuck Dunes State Park, Michigan, USA, and environmental parameters were recorded at each collection site. Offspring plants were raised in climate chambers and exposed to one of three temperature treatments: regular occurrence of frost, heat, or constant control conditions. Several traits were assessed: plant growth, time to flowering, and frost and heat resistance.
KEY RESULTS
The strongest trait-environment association was between a fast switch to sexual reproduction and weaker growth under frost, and growing in the open, away from trees. The second strongest association was between the trait combination of small plant size and early flowering under control conditions combined with large size under frost, and the combination of environmental conditions of growing close to trees, at low vegetation cover, on dune bottoms. Gene expression analysis by RNA-seq revealed candidate genes involved in multivariate trait differentiation.
CONCLUSIONS
The results support the hypothesis that in natural populations, many environmental factors impose selection, and that they affect multiple traits, with the relative direction of trait change being complex. The results highlight that heterogeneity in the selection environment over small spatial scales is a main driver of the maintenance of adaptive genetic variation within populations.
背景和目的
在非常短的空间尺度上，一个物种的栖息地在多个非生物和生物因素方面可能存在差异。这些因素可能对多个特征施加自然选择，并导致种群内的遗传分化。我们通过将环境变化与基因型特征值和基因表达水平的差异联系起来，研究了沙丘景观中一种植物物种的多变量遗传分化，以找到微观地理适应的特征和候选基因。
方法
在美国密歇根州绍格塔克沙丘州立公园收集了拟南芥 lyrata 的母本种子家族，并在每个采集点记录环境参数。后代植物在气候室中生长，并暴露于三种温度处理之一：经常发生霜冻、高温或恒定控制条件。评估了几个特征：植物生长、开花时间、以及对霜冻和高温的抗性。
主要结果
最强的特征-环境关联是快速转变为有性繁殖和在霜冻下较弱的生长之间的关联，以及在远离树木的开阔处生长。第二个最强的关联是在控制条件下的小植株大小和早开花的特征组合与在霜冻下的大植株大小之间的关联，以及靠近树木、植被覆盖低、在沙丘底部生长的环境条件组合之间的关联。通过 RNA-seq 进行的基因表达分析揭示了参与多变量特征分化的候选基因。
结论
结果支持了这样一种假设，即在自然种群中，许多环境因素施加选择，并且它们影响多个特征，特征变化的相对方向是复杂的。结果强调了小空间尺度上选择环境的异质性是维持种群内适应性遗传变异的主要驱动力。
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