Ren Jing, Chen Liang, Jin Xiaoli, Zhang Miaomiao, You Frank M, Wang Jirui, Frenkel Vladimir, Yin Xuegui, Nevo Eviatar, Sun Dongfa, Luo Ming-Cheng, Peng Junhua
Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University Dezhou, China.
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Chinese Academy of Sciences Wuhan, China.
Front Plant Sci. 2017 Mar 14;8:258. doi: 10.3389/fpls.2017.00258. eCollection 2017.
Whole-genome scans with large number of genetic markers provide the opportunity to investigate local adaptation in natural populations and identify candidate genes under positive selection. In the present study, adaptation genetic differentiation associated with solar radiation was investigated using 695 polymorphic SNP markers in wild emmer wheat originated in a micro-site at Yehudiyya, Israel. The test involved two solar radiation niches: (1) sun, in-between trees; and (2) shade, under tree canopy, separated apart by a distance of 2-4 m. Analysis of molecular variance showed a small (0.53%) but significant portion of overall variation between the sun and shade micro-niches, indicating a non-ignorable genetic differentiation between sun and shade habitats. Fifty SNP markers showed a medium (0.05 ≤ ≤ 0.15) or high genetic differentiation ( > 0.15). A total of 21 outlier loci under positive selection were identified by using four different -outlier testing algorithms. The markers and genome locations under positive selection are consistent with the known patterns of selection. These results suggested that genetic differentiation between sun and shade habitats is substantial, radiation-associated, and therefore ecologically determined. Hence, the results of this study reflected effects of natural selection through solar radiation on EST-related SNP genetic diversity, resulting presumably in different adaptive complexes at a micro-scale divergence. The present work highlights the evolutionary theory and application significance of solar radiation-driven natural selection in wheat improvement.
使用大量遗传标记进行全基因组扫描，为研究自然种群的局部适应性以及识别正选择下的候选基因提供了机会。在本研究中，利用来自以色列耶胡迪亚一个微地点的野生二粒小麦中的695个多态性SNP标记，研究了与太阳辐射相关的适应性遗传分化。试验涉及两个太阳辐射生态位：（1）阳光充足、树木之间的区域；（2）树荫下、树冠遮蔽的区域，两者相距2 - 4米。分子方差分析表明，阳光充足和树荫下的微生态位之间总体变异中有一小部分（0.53%）但具有显著差异，这表明阳光充足和树荫下的栖息地之间存在不可忽视的遗传分化。50个SNP标记显示出中等（0.05≤Fst≤0.15）或高度（Fst＞0.15）的遗传分化。通过使用四种不同的Fst - 离群值检验算法，共鉴定出21个正选择下的离群位点。正选择下的标记和基因组位置与已知的选择模式一致。这些结果表明，阳光充足和树荫下栖息地之间的遗传分化很大，与辐射相关，因此是由生态因素决定的。因此，本研究结果反映了太阳辐射引起的自然选择对与EST相关的SNP遗传多样性的影响，可能导致在微观尺度差异上形成不同的适应性复合体。目前的工作突出了太阳辐射驱动的自然选择在小麦改良中的进化理论和应用意义。
