Volis Sergei, Ormanbekova Danara, Yermekbayev Kanat, Song Minshu, Shulgina Irina
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650204, China.
Institute of Plant Biology and Biotechnology, 45 Timiryazev St., Almaty 050040, Kazakhstan.
PLoS One. 2015 Mar 20;10(3):e0121153. doi: 10.1371/journal.pone.0121153. eCollection 2015.
Detecting local adaptation and its spatial scale is one of the most important questions of evolutionary biology. However, recognition of the effect of local selection can be challenging when there is considerable environmental variation across the distance at the whole species range. We analyzed patterns of local adaptation in emmer wheat, Triticum dicoccoides, at two spatial scales, small (inter-population distance less than one km) and large (inter-population distance more than 50 km) using several approaches. Plants originating from four distinct habitats at two geographic scales (cold edge, arid edge and two topographically dissimilar core locations) were reciprocally transplanted and their success over time was measured as 1) lifetime fitness in a year of planting, and 2) population growth four years after planting. In addition, we analyzed molecular (SSR) and quantitative trait variation and calculated the QST/FST ratio. No home advantage was detected at the small spatial scale. At the large spatial scale, home advantage was detected for the core population and the cold edge population in the year of introduction via measuring life-time plant performance. However, superior performance of the arid edge population in its own environment was evident only after several generations via measuring experimental population growth rate through genotyping with SSRs allowing counting the number of plants and seeds per introduced genotype per site. These results highlight the importance of multi-generation surveys of population growth rate in local adaptation testing. Despite predominant self-fertilization of T. dicoccoides and the associated high degree of structuring of genetic variation, the results of the QST - FST comparison were in general agreement with the pattern of local adaptation at the two spatial scales detected by reciprocal transplanting.
检测局部适应性及其空间尺度是进化生物学最重要的问题之一。然而，当整个物种分布范围内的距离存在相当大的环境变异时，识别局部选择的影响可能具有挑战性。我们使用几种方法，在两个空间尺度上分析了野生二粒小麦（Triticum dicoccoides）的局部适应模式，小尺度（种群间距离小于1公里）和大尺度（种群间距离大于50公里）。来自两个地理尺度上四个不同栖息地（寒冷边缘、干旱边缘和两个地形不同的核心位置）的植物进行了相互移栽，并将它们随时间的成功情况衡量为：1）种植年份的终生适合度，以及2）种植四年后的种群增长。此外，我们分析了分子（SSR）和数量性状变异，并计算了QST/FST比率。在小空间尺度上未检测到本土优势。在大空间尺度上，通过测量引入年份的终生植物表现，检测到核心种群和寒冷边缘种群的本土优势。然而，干旱边缘种群在其自身环境中的优越表现仅在几代之后才明显，这是通过使用SSR进行基因分型来测量实验种群增长率得以实现的，该方法能够统计每个引入基因型在每个地点的植物和种子数量。这些结果突出了在局部适应测试中对种群增长率进行多代调查的重要性。尽管野生二粒小麦主要进行自花授粉且遗传变异具有高度的结构化，但QST - FST比较的结果总体上与通过相互移栽检测到的两个空间尺度上的局部适应模式一致。
