Knowledge Resource Center for Ecological Environment in Arid Area
| 燕麦属系统发育及六倍体栽培燕麦基因组起源研究 | |
| 其他题名 | Molecular Phylogeny of Avena and Genomic Origins of hexaploid A. sativa and A. nuda |
| 林磊 | |
| 出版年 | 2016 |
| 学位类型 | 硕士 |
| 导师 | 刘青 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 燕麦属(Avena L.)隶属于禾本科早熟禾族(Poeae, Poaceae)，约有29种，作为粮食、饲料、工业原料具有重要经济价值，包括禾谷类作物普通栽培燕麦(A. sativa)和大粒裸燕麦(A. nuda)。本文在系统研究燕麦属植物地理分布、小穗形态学和籽实学特征的基础上，结合分子系统学证据，重建燕麦属系统发育关系，深化理解普通栽培燕麦和大粒裸燕麦的亲本来源，主要研究结果如下：一、燕麦属植物地理分布。燕麦属植物约有29种，主要分布在欧洲、地中海地区、北非、西亚、东亚和美洲。中国有4种，分布于华北、西北、西南各省（区）的高海拔地区。传统分类燕麦属下分7个组，分别是多年生燕麦组[sect. Avenotrichon (Holub) Baum]、偏凸燕麦组(sect. Ventricosa Baum)、耕地燕麦组(sect. Agraria Baum)、软果燕麦组(sect. Tenuicarpa Baum)、埃塞俄比亚燕麦组(sect. Ethiopica Baum)、厚果燕麦组(sect. Pachycarpa Baum)和真燕麦组(sect. Avena)。其中，埃塞俄比亚燕麦组分布在埃塞俄比亚、沙特阿拉伯、也门，其他6个组分布在欧洲、地中海、西北非洲、西亚、东亚和美洲地区。地中海、西北非洲、西亚地区分布有除埃塞俄比亚燕麦组之外的所有6个组，因此推断该地区可能是燕麦属的现代分布中心和多样性中心，而燕麦属的起源地尚需确证。二、燕麦属小穗形态学研究。收集、栽培燕麦属植物材料，借阅国内外标本，观察燕麦属花序及小穗形态学特征，结合文献资料编制燕麦属检索表。研究结果支持把燕麦属划分为两个组：不等颖组(Inaequaliglumes)和等颖组(Equaliglumes)，在等颖组下又可根据外稃顶端齿裂程度划分为：具小芒亚组(Aristulatae)和具细齿亚组(Denticulatae)。在具小芒亚组中，结合形态种和生物种的概念，我们将A. hispanica归并为砂燕麦(Avena strigosa)异名，将小硬毛燕麦(A. hirtula)、A. lusitanica和A. matritensis归并为沙漠燕麦(A. wiestii)异名。三、燕麦属籽实学研究。燕麦属颖果有纺锤形、倒披针形、椭圆形3种形状，条纹、棱纹、网纹3种纹饰。燕麦属颖果形状、纹饰和花柱基宿存模式具有有限的属下分类学意义，颖果大小和表面大毛密度具有种间鉴定价值，而颖果腹面形态、压扁方式、胚比不具有种间鉴定价值。大穗燕麦(Avena macrostachya)颖果纺锤形，条纹纹饰，隶属于燕麦属颖果微形态特征的变异范围。大粒裸燕麦(A. nuda)与普通栽培燕麦(A. sativa)颖果大小、形状及纹饰特征的差异支持将大粒裸燕麦作为独立种处理。燕麦属颖果大小、表面大毛密度、胚比变异幅度大，推测与分布区广幅的气候变异相适应，凹腹面颖果体积相对缩减，有利于颖果快速发育、成熟，推测与燕麦属植物在温带、寒带分布区适生期较短相适应。 四、燕麦属分子系统发育研究。本研究选择三个低拷贝核基因(ppc-B1、GBSSI和gpa1)和三个叶绿体 DNA片段(ndhA intron、rpl32-trnL和rps16 intron)，针对燕麦属27种89样品，外类群7属16种20样品，进行最大似然法和贝叶斯推测分析，分子钟估测燕麦属主要事件分化时间，研究结果包括：基于核基因ppc-B1、GBSSI、gpa1片段和叶绿体DNA片段分子系统发育证据，支持燕麦属单系性；支持燕麦属属下划分为2个遗传谱系：C基因组谱系和A基因组谱系；支持普通栽培燕麦AC基因组四倍体物种 × D基因组二倍体物种杂交起源假说，并且认为长颖燕麦(Avena longiglumis)和短燕麦(A. brevis)可能是普通栽培燕麦A/D基因组亲本供体；分子钟推测燕麦属冠群分化时间为早中新世(Miocene)20.04百万年前，本研究为燕麦属作物地中海地区最古老的禾谷类作物的假说提供证据。 |
| 英文摘要 | Avena L. (Poeae, Poaceae) is a genus of 29 species, comprising economically important species of cereal crops, fodder and industry materials. Cereal crops such as cultivated oat (A. sativa) and naked oat (A. nuda) are included in the genus. Here we used a nearly complete sampling of Avena, covering the morphological diversity and geographic ranges of seven sections, in conjunction with geographical distribution, spikelet and caryopsis morphology, phylogenetic analysis, and divergence time estimation based on nuclear and plastid DNA sequence data to address the complex interspecific phylogeny of Avena and enhance our understanding of the exact genome donors for cultivated oat and naked oat. The results are herein brief as follows:Geographical distribution of Avena: The results showed that 29 species in Avena were distributed in Europe, Mediterranean regions, Northern Africa, Western Asia, Eastern Asia, and the Americas. In China, four species of Avena distribute in high altitude areas in the northern, northwestern, and southwestern provinces. Seven sections are traditionally delimited in Avena, including sect. Avenotrichon (Holub) Baum, sect. Ventricosa Baum, sect. Agraria Baum, sect. Tenuicarpa Baum, sect. Ethiopica Baum, sect. Pachycarpa Baum, and sect. Avena. The sect. Ethiopica occurs in Ethiopia, Saudi Arabia, and Yemen, and the remaining six sections occur in Mediterranean regions, southwestern Europe, Northwestern Africa, Western Asia, Eastern Asia, and the Americas. The results suggest that the Mediterranean regions, Northwestern Africa, and Western Asia are the distribution centers and diversification centers of Avena, while the origin center of Avena needs to be further studied.Spikelet morphology of Avena: Caryopses of Avena were obtained from seedlings and dry herbarium specimens deposited at IBSC, K, and US. The inflorescence and spikelet morphology of Avena has been investigated using Stereo Microscope. Avena can be divided into two sections: Inaequaliglumes(glumes markedly unequal in size); Equaliglumes (glumes equal or almost equal in size). Equaliglumes can be divided into two subclades according to lemma tip characteristic: Aristulate (lemma tips biaristulate); Denticulate (lemma tips bidenticulate). Based on glumes shape, the structure of the lemma tips, the mode of the spikelet disarticulation at maturity in morpholgical characteristics and the genome type, A. hispanica has been treated as a synonym of A. trigosa, and A. hirtula, A. lusitanica and A. matritensis were treated as synonyms of A. wiestii.Caryopsis morphology of Avena: There are three shapes of caryopses including fusiform, oblanceolate and elliptic, and three spermoderm sculpturing patterns including striate, ribbed and reticulate in Avena. Caryopsis shapes, spermoderm sculpturing patterns and stylopodium persistence patterns show limited taxonomic significance at the infrageneric level, and caryopsis size and macrohair density are of important diagnostic characters at the interspecific level, while caryopsis ventral face, compression, and embryo proportion have limited diagnostic significance at the interspecific level in Avena. Avena macrostachya Balansa ex Coss. & Durieu is treated as a member of Avena due to its caryopsis characters of fusiform and striate sculpturing pattern falling within the variation scope of caryopsis micromorphological characters of Avena. The differences of caryopsis size, shapes, spermoderm sculpturing patterns between A. nuda L. and A. sativa L. support that A. nuda should be treated as a separate species. The wide variation ranges of caryopsis size, macrohair density and embryo proportion indicate that they are the adaptive consequences of wide variation range of climate condition across the geographical distribution region of Avena. The caryopses of concave ventral face have a relatively small bulk, which may have aided rapid development and maturation, a rhythm that is of particular value in short growth period in temperate and cold distribution region for Avena.Phylogeny and temporal divergence of Avena: Sequence data of three low-copy nuclear (LCN) genes, phosphoenolpyruvate carboxylase 4 (Pepc4), granule-bound starch synthase I (GBSSI), G protein alpha subunit 1(gpa1) and three cpDNA (ndhA intron, rpl32-trnL, and rps16 intron), from 89 accessions of Avena plus 20 accessions of outgroups were used for maximum likelihood (ML) and Bayesian inference (BI) analyses. Bayesian dating based on three cpDNA region (ndhA intron, rpl32-trnL, and rps16 intron) was used to estimate the divergence ages of major lineages in Avena. The monophyly of Avena is strongly supported by nuclear (ppcB1, GBSSI, and gpa1) and plastid data. Avena was divided into two clades: C-genome clade and A-genome clade. Our results support the hypothesis that oat (Avena sativa) originated from the allopolyploidization events after the hybridization between AC genome tetraploids and unknown D-genome diploids. Avena longiglumis and A. brevis maybe the A/D genome parent of oat. Avena is one of the most ancient cereal genus of the Mediterranean Basin because the uncorrelated-rates relaxed molecular clock suggests that the crown node age of Avena was 20.04 [95% highest posterior density (HPD) 3.56–35.06] mya in the early Miocene. |
| 中文关键词 | 燕麦属 ; 地中海地区 ; 低拷贝核基因 ; 系统发育 ; 小穗和颖果形态 |
| 英文关键词 | Avena Circum-Mediterranean region Low-copy nuclear gene Phylogeny Spikelet and caryopsis morphology |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 植物学 |
| 来源机构 | 中国科学院华南植物园 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287728 |
| 推荐引用方式 GB/T 7714 | 林磊. 燕麦属系统发育及六倍体栽培燕麦基因组起源研究[D]. 中国科学院大学,2016. |
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