Divergent pattern between phenotypic and genetic variation in Scots pine

第一作者：David Hall

第一单位：于默奥大学

通讯作者：Xiao-Ru Wang

 Abstract 

背景回顾：In boreal forests, autumn frost tolerance in seedlings is a critical fitness component because it determines survival rates during regeneration. 

研究目的与方法：To understand the forces that drive local adaptation in this trait, we conducted freezing tests in a common garden setting for 54 Pinus sylvestris (Scots pine) populations (>5000 seedlings) collected across Scandinavia into Western Russia, and genotyped 24 of these populations (>900 seedlings) at >10,000 SNPs.

结果1-表型变异：Variation in cold hardiness among populations, as measured by QST, was above 80% and followed a distinct cline along latitude and longitude, demonstrating significant adaptation to climate at origin.

结果2-遗传分化：In contrast, the genetic differentiation was very weak (mean FST 0.37%).

结果3-SNP标记分布特征：Despite even allele frequency distribution in the vast majority of SNPs among all populations, a few rare alleles appeared at very high or at fixation in marginal populations restricted to Northwestern Fennoscandia.

结果4-基因型与环境、表型关联：Genotype-environment associations showed that climate variables explained 2.9% of the genetic differentiation, while genotype-phenotype associations revealed a high marker-estimated heritability of frost hardiness 0.56, but identified no major loci.

展望：Very extensive gene flow, strong local adaptation and signals of complex demographic history across markers are interesting topics of forthcoming studies on this species to better clarify signatures of selection and demography.

 摘 要 

在北方森林中，幼苗的秋霜耐受性是非常关键的适应性状，其决定了再生过程中的存活率。为了了解驱动该性状局域适应的因素，作者在试验地中对从斯堪的纳维亚到俄罗斯西部采集的54个樟子松种群（>5000株幼苗）进行了抗冻测试，并对其中的24个种群（>900株幼苗）在超过10000个SNP位点上进行了基因型分型。经QST测定，种群间耐寒性的变异在80%以上，并沿纬度和经度呈明显的梯度变化，表明不同地域的种群对气候有明显的局域适应性。相反，这些种群的遗传分化很弱，平均FST值仅为0.37%。尽管等位基因频率在绝大多数SNP中分布均匀，但在分布在芬诺斯坎迪亚西北部的边缘群体中，少数罕见的等位基因出现频率非常高或者固定。基因型-环境的关联显示，气候变量解释了2.9%的遗传分化；而基因型-表型的关联显示，标记估计的抗冻性遗传力较高，为0.56，但未能鉴定到主效基因座。广泛的基因流、较强的局域适应以及复杂的群体历史信号是未来对于该物种的几个比较有意思的研究方向，有助于我们更好地阐明选择和群体特征。

 通讯作者 

doi: https://doi.org/10.1016/j.xplc.2020.100139

Journal: Plant Communications

Published online: Dec 29, 2020