松嫩平原异质生境芦苇表型变异及其分子生态学研究

发布时间：2018-01-08 07:32

本文关键词：松嫩平原异质生境芦苇表型变异及其分子生态学研究　出处：《东北师范大学》2017年博士论文　论文类型：学位论文

【摘要】：物种形成虽然是一个漫长的时间过程,但经常从占据不同生态环境的种群的适应性分歧开始。遗传分化是生物适应异质生境的重要机制之一。异质生境间和生境内植物的遗传变异、表观遗传变异为自然选择和适应性进化提供了原材料。探讨植物在异质生境间和生境内表型差异的遗传、表观遗传机理及其与适应性进化的关系是分子生态学的主流研究内容之一。然而在小空间尺度上这方面的研究还不多见。芦苇(Phragmites australis)是世界广布种,在松嫩平原的湿地、沙地和草地广泛生长,其营养生长期为各种家畜采食的优良牧草,也是当地盐碱化草甸生态恢复的主要植物。本研究以小空间尺度上松嫩平原异质生境的芦苇(Phragmites australis)、毛芦苇(Phragmites hirsuta)为材料,通过野外调查、实验室测定、AFLP(Amplified fragment length polymorphism)和MSAP(Methylation-sensitive amplified polymorphism)分子标记检测和同质园实验,运用分子生态学的统计分析方法,探究异质生境基础上的表型差异及其遗传、表观遗传基础,以及适应性进化的意义。得到主要结果如下:(1)在土壤理化特征差异明显的4种生境,芦苇表型数量特征差异显著。季节性积水的低洼碱化草甸土生境(H1)和沙地生境(H4)的株高、叶片等生长特征和生物量明显大于典型碱化草甸土的羊草(Leymus chinensis)芦苇混生群落的生境(H3)和明碱斑的生境(H2),大多数情况下H2最低。H1和H3的茎生物量分配较大,H4的叶生物量分配较大,H2的叶鞘生物量分配较大。土壤含水量、全磷、全氮均与芦苇的生长呈正相关,它们和有机质含量与茎生物量分配呈正相关,与叶生物量分配呈负相关;土壤pH、电导率、硝态氮、Cl-、SO42-、Na+或K+与芦苇生长呈负相关,随着土壤电导率、Cl-、Na+或K+的增加,茎生物量分配呈先增后减的趋势,叶生物量分配呈先减后增、叶鞘生物量分配呈增加的趋势;Mg2+和Ca2+与芦苇生长呈正相关。叶生物量分配与茎生物量分配之间存在权衡现象。数量性状之间、生物量分配之间的相关关系以及异速生长规律在生境间存在显著差异。(2)在小空间尺度上,异质生境内和种群内芦苇存在遗传多态。H1和H3芦苇比H2和H4有更高的遗传多样性,这和生境幅度变异假说一致。生境基础上碱地(H1、H2、H3)与沙地(H4)间遗传分化更为明显。应用修饰的FDIST,Bayescan和Samβada3种方法探测到33个异常值位点,土壤Ca2+、全磷、Mg2+、pH等是自然选择压力主要环境因子。本章结果支持“带有基因流的分歧”(“divergence-with-gene-flow”)模型,为进一步研究局域适应提供了基因组水平的数据。(3)在MSAP分析中约有2/3的位点是甲基化敏感位点(MSL)。异质生境间4种类型甲基化模式所占比例不同。生境内、种群内表观遗传多样性较高,H1、H2和H3明显高于H4。4种生境间表观遗传分化显著,碱地与沙地之间更明显。H1与H3、H2与H3的表观遗传分化明显大于遗传分化。遗传变异与表观遗传变异显著相关。生境间表观遗传分化与适应性遗传分歧之间相关。植株表型特征与表观遗传多样性的关系要比与遗传多样性的关系更为密切;遗传多样性参数与土壤全磷、Cl-、Ca2+含量呈显著相关关系,而表观遗传多样性参数与土壤含水量、全磷、全氮以及有机质呈显著相关关系,表观遗传多样性受土壤营养成分的影响更大。(4)通过AFLP标记,采用UPGMA、STRUCTURE、主坐标分析方法对芦苇、毛芦苇和日本苇(Phragmites japonica)做分子水平分析,结果显示,芦苇、毛芦苇组内H3和H4明显分开,长春市南湖公园芦苇和H3、H4的芦苇遗传距离较近,意味芦苇和毛芦苇之间的分化是先于地理分化、生境分化的。MSAP标记显示芦苇和毛芦苇显著的表观遗传分化,芦苇、毛芦苇组内H3和H4也明显分开,反映出芦苇与毛芦苇之间以DNA甲基化为基础的表观遗传位点经历了比异质生境引起的分化更为强烈的分化。推测毛芦苇处在从芦苇中分化出来的早中期。(5)野外调查发现H2(碱斑)中芦苇的叶绿素a(Chla),叶绿素b(Chlb),总叶绿素(Chl(a+b)),类胡萝卜素(Car)浓度以及总叶绿素/类胡萝卜素(Chl(a+b)/Car ratio)均显著低于H1。只有Chla/Chlb没有显著变化。同质园实验中小空间尺度上Chla,、Chlb、Chl(a+b)、和Car浓度存在局域适应现象。应用种群基因组方法FDIST,Bayescan和Bayenv探测到异常值位点(outlier loci)和形态分化系数-遗传分化系数(QST-FST)比较分析均支持局域适应的结论。土壤含水量、pH和电导率均可形成自然选择压力而引起光合色素的适应性分歧。本研究有助于小尺度异质生境不同表型芦苇的遗传和表观遗传基础的理解,丰富了芦苇分子生态学的研究内容,可为生态适应性、生物抗逆性、芦苇属分类的研究、以及包括生态恢复、遗传资源保护、遗传改良在内的应用实践提供科学参考或理论依据。
[Abstract]:The formation of species although it is a long time, but often from the adaptability differences occupy different ecological environment. Population genetic differentiation is one of the important mechanisms of heterogeneous habitat biological adaptation. The genetic variation between heterogeneous habitats and habitat within plants, epigenetic variation in natural selection and adaptive evolution provides the raw material of. In plant genetic heterogeneity among habitats and habitat phenotypic differences, the epigenetic mechanism and its relationship with adaptive evolution is one of the main research contents of molecular ecology. However, research on this aspect at small spatial scales are rare. Reed (Phragmites australis) is a world wide distributed species in the Songnen Plain Wetland sand and grass, widely grown, the vegetative growth stage for various animal feed forage for food, the main plant is a local salinization meadow ecological restoration. In this study, a small space On the scale of heterogeneous habitats in Songnen Plain reed (Phragmites australis), Mao Luwei (Phragmites hirsuta) as material, through field investigation, laboratory test, AFLP (Amplified fragment length polymorphism) and MSAP (Methylation-sensitive amplified polymorphism) molecular markers and common garden experiments, using statistical analysis method to explore the molecular ecology, phenotypic differences in heterogeneous habitat based and on the genetic, epigenetic basis and significance of adaptive evolution. The main results are as follows: (1) on the physicochemical characteristics of the difference between the 4 habitats significantly soil, quantitative differences significant. Phenotypic characteristics of Phragmites low-lying meadow alkali soil habitat seasonal water (H1) and sandy habitat (H4) plant height leaves, growth characteristics and biomass was significantly higher than that of typical alkalized meadow soil of Leymus chinensis (Leymus chinensis) habitats, mixed communities (H3) and alkali spot The habitat (H2), stem biomass H2 minimum.H1 and H3 distribution in most cases is large, leaf biomass distribution of H4 large amount of leaf sheath distribution of H2 greatly. Biological soil moisture, total phosphorus, total nitrogen were positively related to growth of reed, they positively with organic matter content and stem biomass allocation correlation was negatively correlated with leaf biomass allocation; soil pH, conductivity, nitrate nitrogen, Cl-, SO42-, Na+ or K+ and reed growth was negatively correlated with soil conductivity, Cl-, Na+ or K+ increased the stem biomass allocation increased firstly and then decreased, the leaf biomass allocation was first decreased and then increased, leaf biomass allocation increased; Mg2+ and Ca2+ and reed growth was positively correlated. There is a trade-off phenomenon between leaf biomass allocation and stem biomass allocation. Quantitative traits between the relationship between biomass allocation and allometry have significant differences in habitat (2) in between. The small spatial scale, heterogeneous habitat and population genetic polymorphism of.H1 and H3 in reed reed than H2 and H4 have higher genetic diversity, and the favorable habitat. Habitat Based on amplitude variation hypothesis (H1, H2, alkaline H3) and sand (H4) genetic differentiation among the applications of modified is more obvious. FDIST, Bayescan and Sam beta ADA3 method to detect 33 outlier loci, soil Ca2+, total phosphorus, Mg2+, pH are the main environmental factors of natural selection pressure. The results of this chapter support "with gene flow differences" ("divergence-with-gene-flow") model, provides the genome level data for further study on local adaptation. (3) in the MSAP analysis about 2/3 sites methylation sensitive sites (MSL). Among the 4 types of heterogeneous habitat methylation patterns in different proportion. Chinese population apparent higher genetic diversity, H1, H2 and H3 significantly higher than the H4.4 table between habitats view Significant genetic differentiation between soil and sand is more obvious,.H1 and H3, H2 and H3 on genetic differentiation table is significantly greater than the genetic variation and genetic differentiation. The apparent significant genetic variation among habitats. The apparent genetic differentiation and genetic differences between related plant adaptability. The phenotypic characteristics and apparent genetic diversity than genetic diversity and relationship more closely; the genetic diversity parameters and soil total phosphorus, Cl-, there was a significant correlation between the content of Ca2+, and the apparent genetic diversity parameters and soil moisture content, total phosphorus, total nitrogen and organic matter were significant correlation between the effect of apparent genetic diversity by soil nutrients more. (4) by AFLP markers, using UPGMA, STRUCTURE, principal coordinate analysis method of reed, reed and reed hair Japan (Phragmites japonica) to do the molecular analysis, results showed that reed, reed hair groups within H3 and H4 significantly separated, Changchun City South Lake Park reed and reed H3, H4's genetic distance is short, means that the differentiation between the reed and reed hairs are prior to geographical differentiation,.MSAP marker showed habitat differentiation of reed and reed hair significant epigenetic differentiation, reed, reed group H3 and H4 in hair was also separated based epigenetic site experience the differentiation caused by heterogeneous habitat is more intense than the differentiation between reed and reed of hair reflected by DNA methyl. In the early stage of differentiation that Mao reed from reed. (5) field investigation found that H2 (alkali spot) in reed chlorophyll a (Chla), chlorophyll b (Chlb), total the chlorophyll (Chl (a+b)), carotenoid (Car) concentration and total chlorophyll / carotenoid (Chl (a+b) /Car ratio) were significantly lower than that of H1. only Chla/Chlb did not change significantly. The small spatial scale common garden experiment, Chla, Chlb, Chl (a+b), and the existence of local concentration of Car To adapt to the phenomenon. The application of FDIST method Bayescan and Bayenv genome species, to detect outlier loci (outlier loci) and the morphological differentiation coefficient of genetic differentiation coefficient (QST-FST) comparative analysis to support local adaptation. The conclusion of soil moisture, pH and conductivity can be formed by natural selection pressure adaptability differences of photosynthetic pigments in this research. There are genetic help to small scale heterogeneous habitats with different phenotypes of reed and superficial understanding of the genetic basis, enrich the research content of reed for molecular ecology, ecological adaptability, biological resistance, study on genus and reed, including ecological restoration, protection of genetic resources, and provide scientific reference and theoretical basis of the application of practice, genetic improvement.

【学位授予单位】：东北师范大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：Q948

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