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林业科学 ›› 2019, Vol. 55 ›› Issue (3): 43-53.doi: 10.11707/j.1001-7488.20190305

• 论文与研究报告 • 上一篇    下一篇

基于ITS和cpDNA序列的梭梭和白梭梭物种分化

孙芳芳1,2, 聂迎彬3, 马松梅1, 魏博2, 吉万全4   

  1. 1. 石河子大学理学院 石河子 832000;
    2. 石河子大学生命科学学院 绿洲城镇与山盆系统生态兵团重点实验室 石河子 832000;
    3. 新疆农垦科学院作物研究所 石河子 832000;
    4. 西北农林科技大学农学院 杨凌 712100
  • 收稿日期:2018-04-25 修回日期:2018-06-21 出版日期:2019-03-25 发布日期:2019-04-17
  • 基金资助:
    国家自然科学基金项目(41561007;41261011);旱区作物逆境生物学国家重点实验室(西北农林大学)开放基金项目(CSBAA2015014)。

Species Differentiation of Haloxylon ammodendron and Haloxylon persicum Based on ITS and cpDNA Sequences

Sun Fangfang1,2, Nie Yingbin3, Ma Songmei1, Wei Bo2, Ji Wanquan4   

  1. 1. College of Science, Shihezi University Shihezi 832000;
    2. Key Laboratory of Ecological Corps for Oasis City and Mountain Basin System College of Life Sciences, Shihezi University Shihezi 832000;
    3. Institute of Crop Research, Xinjiang Academy of Agri-Reclamation Sciences Shihezi 832000;
    4. College of Agronomy, Northwest A & F University Yangling 712100
  • Received:2018-04-25 Revised:2018-06-21 Online:2019-03-25 Published:2019-04-17

摘要: [目的]基于nrDNA和cpDNA 2种基因,探讨中国同域分布的梭梭和白梭梭的物种分化,分析2种基因的单片段及其片段组合对2种植物的物种鉴别力,并分析生态位分化的程度及其对物种进化的影响,为梭梭和白梭梭的系统发育和谱系地理等研究提供基础数据。[方法]基于2个nrDNA序列(ITS2、ITS1-ITS4)和3个cpDNA非编码区序列(trnS-trnG、rps4和trnV),对古尔班通古特沙漠南缘同域分布的梭梭和白梭梭共30个个体进行序列分析;利用距离法(基于Kimura 2-parameter)研究2种植物的遗传分化;基于贝叶斯方法分析个体间的分子系统关系;并利用距离法、系统发育树法、BLAST比对法和诊断特征法评价ITS和cpDNA的单序列及其组合对2种植物的物种鉴别力。在此基础上,利用生态位分析软件ENMTools V1.4定量分析梭梭与白梭梭生态位分化的程度。[结果] 1)对于梭梭和白梭梭,2个ITS序列拼接比对的总长均为1 117 bp,G+C含量平均分别为34.74%和34.82%,总的信息位点数分别占片段总长的2.33%和1.43%;3个cpDNA序列拼接比对的总长均为2 344 bp,G+C含量平均分别为59.62%和59.39%,信息位点数分别占片段总长的0.68%和0.43%。2)基于ITS和cpDNA序列组合构建的贝叶斯系统发育树都表明梭梭和白梭梭各聚为一支。3)基于ITS和cpDNA序列组合计算的2种植物的种间最小遗传距离均大于种内的最大遗传距离,并且种间种内都存在1个明显的距离间隙,表明本研究所用的ITS和cpDNA的序列组合可以作为鉴定梭梭和白梭梭的DNA条形码序列。4)基于4种方法评价的ITS和cpDNA序列对梭梭和白梭梭的物种鉴别力表明:2个ITS的单序列及其序列组合的鉴别率均为100%;cpDNA序列中,rps4的单序列及其与trnS-trnG,trnV的两两序列组合的鉴别率均为0,而trnS-trnG,trnV的单序列及其序列组合,以及trnS-trnG+trnV+rps4组合的鉴别率均为100%。5)生态位参数D值和I值的观察值和一致性检验的模拟值都集中在0.65和0.90左右,表明梭梭和白梭梭的生态位分化不明显。[结论]基于ITS和cpDNA序列组合,梭梭和白梭梭物种间的遗传分化明显,分子系统关系清楚;ITS和cpDNA序列组合都可以作为鉴定梭梭和白梭梭的DNA条形码序列;梭梭和白梭梭的生态位分化不明显,说明生态因素很可能对2种植物的分化与进化没有起到明显的作用,2种植物很可能也具有相近的进化历史。本研究的结论可以为梭梭和白梭梭的系统发育、遗传和进化研究提供重要的理论依据和数据支撑。

关键词: 梭梭, 白梭梭, ITS序列, cpDNA序列, 物种分化, 分子系统关系, 生态位分化

Abstract: [Objective] The nrDNA and cpDNA were used to determine the genetic differentiation between Haloxylon ammodendron and H. persicum, two species with sympatric distribution in China. The species discrimination ability of each single fragment and its combination of two genes was compared. In addition, we investigated the degree of ecological niche divergence and its impact on species evolution. Our study could provide important basic information for the understanding of phylogeny and phylogeography of H. ammodendron and H. persicum.[Method] We sampled 30 H. ammodendron and H. persicum individuals from the southern Gurbantunggut Desert. We performed sequence analyses using two nuclear gene sequences (ITS2, ITS1-ITS4) and three cpDNA non-coding regions (trnS-trnG, rps4 and trnV). The distance method (based on Kimura 2-parameter model) was used to analyze genetic differentiation of the two species. Bayesian method were employed to explore molecular phylogeny among individuals. Four method (genetic distances, phylogenetic trees, BLAST, and character-based method) were employed to examine the species discrimination ability of each single fragment and its combination of two genes. On this basis, we used ecological niche analysis software to calculate the ecological niche divergence of H. ammodendron and H. persicum.[Result] 1) For H. ammodendron and H. persicum, the total length of the two combined ITS sequences was all 1 117 bp, the average content of G + C was 34.74% and 34.82%, and the number of information sites accounted for 2.33% and 1.43%, respectively. The total length of the three combined cpDNA non-coding regions are all 2 344 bp, and the average content of G + C was 59.62% and 59.39%, and information sites accounted for 0.68% and 0.43%, respectively. 2) Two distinct clades of H. ammodendron and H. persicum was detected in the two phylogenetic trees. 3)Based on ITS and cpDNA sequences, the minimum interspecific genetic distance of the two species was greater than the maximum intraspecific genetic distance, and an obvious interspecific and intraspecific barcoding gap was found. The sequences combination of ITS and cpDNA can therefore be used as DNA barcode for identification of H. ammodendron and H. persicum. 4) Regarding the species discrimination rate, as calculated by the four method showed:the rate of each single ITS fragment and its combination was all 100%; for trnS-trnG, trnV and its combination, the rate was all 100%; for rps4 and its combination of trnS-trnG or trnV, the identification rate was all 0%. The sequence combinations of trnS-trnG+trnV+rps4 was 100%. 5) The observed values of ecological niche parameters (D-value and I-value) and the simulated values of the identity test were concentrated around 0.65 and 0.90 respectively, indicating a similar ecological niche in H. ammodendron and H. persicum.[Conclusion] Using ITS and cpDNA sequences, we revealed a clear genetic differentiation and molecular phylogeny relationship between individuals of H. ammodendron and H. persicum. Both the ITS and cpDNA sequence combinations could be used as DNA barcode sequences to identify H. ammodendron and H. persicum. There was no evidence for an ecological niche differentiation between H. ammodendron and H. persicum, and ecological factors did not play a significant role in the divergence and evolution of the two species, and the two species were likely to have similar evolutionary history. The conclusion of this study provide an important theoretical basis and data support for studying the phylogenetics, genetics and evolution of H. ammodendron and H. persicum.

Key words: Haloxylon ammodendron, Haloxylon persicum, interspecific differentiations, ITS sequences, cpDNA sequences, molecular phylogenetic relationships, ecological niche differentiation

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