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Genetic variation, cytotype associations and geographical parthenogenesis in the subtropical grass genus Paspalum

亚热带草属雀稗属的遗传变异、细胞型关联和地理孤雌生殖

基本信息

批准号：
262509070
负责人：
Professorin Dr. Elvira Hörandl, since 5/2018
金额：
--
依托单位：
Consejo Nacional de Investigaciones Científicas y Técnicas
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2018-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/262509070?language=en
关键词：
Genetic variation cytotype associations geographical

项目摘要

Polyploidy in flowering plants is one of the most significant spontaneous factors of evolutionary processes, promoting diversification via genome duplication and gene pool fragmentation. In polyploid complexes, the features of their reproductive modes, and pollination syndromes shape genetic variation and population structure. On the other hand, it is widely known that hybridization and polyploidization create a situation of genomic shock linked to changes in reproductive systems such as self-fertility (autogamy) or apomixis (asexually formed seeds). Breeding system character transitions are of particular interest because they affect the amount and distribution of genetic variation within species. Moreover, both self-fertility and apomixis are mechanisms that facilitate uniparental reproduction and enhance colonizing abilities where pollinators or partners for mating are limited (Baker's law). Reproductive assurance through self-fertilization and/or apomixis can promote range expansion outlining geographical cytotype diversity patterns (e.g. geographical parthenogenesis), however the benefit of reproductive assurance might be outweighed by seed discounting, loss of genetic diversity and in selfers, inbreeding depression. Other potential benefits to apomictic reproduction are partitioning of ecological niches and use of the resource space by broad arrays of clones (The Frozen Niche Variation Model) or the colonizing ability of clones with a broad ecological capacity (General Purpose Genotypes). To investigate the complex dynamics determining geographic distributions and cytotype associations in natural populations, we will take advantages of the model system Paspalum (ie. presence of sexual self-sterile / self-fertile diploids, sexual self-sterile / self-fertile tetraploids, apomictic self-fertile tetraploids), and analyse consequences of autogamy vs. allogamy, diploid vs. polyploid, sexual vs. apomictic state characters on genetic variation and cytotype diversity at population level. Ploidy levels and developmental pathways will be studied using flow cytometry. Genetic variation and structuring within and among populations will be assessed using Amplified Fragment Length Polymorphisms and microsatellite markers. The comparison of different cytotypes / reproductive systems will give insights into the importance of these factors for plant evolution and biogeography.

有花植物的多倍性是进化过程中最重要的自发因素之一，通过基因组复制和基因库片段化促进多样性。在多倍体复合体中，它们的繁殖方式和授粉综合征的特征决定了遗传变异和群体结构。另一方面，众所周知，杂交和多倍化产生了与生殖系统变化相关的基因组休克的情况，如自花受精（自花受精）或无融合生殖（无性形成的种子）。育种系统的特征转换是特别感兴趣的，因为它们会影响物种内遗传变异的数量和分布。此外，自花受精和无融合生殖的机制，促进单亲繁殖和提高殖民能力的传粉者或交配的合作伙伴是有限的（贝克定律）。通过自花受精和/或无融合生殖的生殖保证可以促进范围扩大，概述地理细胞型多样性模式（例如地理单性生殖），然而，生殖保证的好处可能超过种子折扣，遗传多样性的损失和自交，近交衰退。无融合生殖的其他潜在好处是生态位的分区和广泛的克隆阵列（冷冻生态位变异模型）或克隆的殖民能力与广泛的生态能力（通用基因型）的资源空间的使用。为了研究自然种群中决定地理分布和细胞型关联的复杂动力学，我们将利用模型系统雀稗（Paspalum）（即。存在有性自交不育/自交可育二倍体、有性自交不育/自交可育四倍体、无融合生殖的自交可育四倍体），并分析自花受精与异花受精、二倍体与多倍体、有性与无融合生殖状态特征对群体水平遗传变异和细胞型多样性的影响。将使用流式细胞术研究倍性水平和发育途径。将使用扩增片段长度多态性和微卫星标记评估群体内和群体间的遗传变异和结构。不同的细胞型/生殖系统的比较将深入了解这些因素对植物进化和植物地理学的重要性。