The genetic basis for local adaptation in Arabidopsis thaliana

拟南芥局部适应的遗传基础

• 批准号: BB/F00656X/1
• 负责人: Andrew Hudson
• 金额: $ 49.98万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FF00656X%2F1
• 关键词: genetic; basis; local; adaptation; Arabidopsis

That different plant species are adapted to different environments is obvious from their natural distributions - bluebells, for example, are limited to shaded woodland. Knowing which characters of the plant are important for such adaptation and how they are specified by genes is fundamental to understanding how the plant evolved, but presents a complex problem. Different species differ in a large range of characters making it difficult either to assess the importance of a particular character alone or in combination with others or to identify the genetic changes that have been involved in its evolution. Here we propose to address the question by examining the basis for adaptation within a single species - Arabidopsis thaliana. More is known about the genetics of Arabidopsis than any other plant and we have recently shown that populations of Arabidopsis within Edinburgh are unexpectedly diverse in both their genetic composition and their behaviour. Some of this variation is probably involved in adaptation - plants from higher altitudes appear genetically programmed to germinate quicker but to flower later in the year, suggesting that they might be adapted to a later spring but not to the lack of summer rain which may affect plants at lower altitude. In contrast, we find that plants from the same habitat have the potential to grow at very different rates, though we do not yet know why such differences might be advantageous to the plants. To understand the basis for this natural variaion, we will test whether genes that are already known to control flowering time are responsible for the differences that we see around Edinburgh, and from this examine whether natural selection for late flowering at higher altitude might have favoured certain genes. Because little is known of the ways in which genes control the rates at which plants grow, we will then identify the genes that are responsible for differences in growth rate within Edinburgh, using hybrids between different plants from the wild. For at least one of these genes, we will determine its DNA sequence and examine how changes in the sequence causes changes in the rate of plant growth. We will then examine whether selection of these genes might explain differences in growth rate between plants growing in the same location. Finally, we will grow plants from various locations, together with hybrids that have different combinations of characters, in habitats at different altitudes to find which combinations of genes and characters are most advantageous in each environment. This will suggest whether the pattern of variation that we see in nature might have arisen because of natural selection. Understanding why organisms are adapted to different environments is important for understanding the process of evolution and for predicting how environmental change will affect the success of crops and natural plant communities. This is particularly relevant to the use of Arabidopsis around Edinburgh where the species is close to its Northerly limit, making it possible to test the effects of unnaturally severe environments on its success (e.g. by growing it at altitudes higher than it is usually found). Identifying which genes control plant growth and how variation in their DNA can increase growth is of further relevance to crop breeding.

从它们的自然分布来看，不同的植物物种适应不同的环境是显而易见的——例如，风信子仅限于阴凉的林地。了解植物的哪些特征对这种适应是重要的，以及这些特征是如何被基因指定的，这是理解植物如何进化的基础，但也提出了一个复杂的问题。不同的物种在很大的性状范围内存在差异，这使得既难以单独评估某一特定性状的重要性，也难以与其他性状结合起来评估其重要性，也难以确定其进化过程中涉及的遗传变化。在这里，我们建议通过研究单一物种-拟南芥的适应基础来解决这个问题。我们对拟南芥的遗传学了解比任何其他植物都多，我们最近表明，爱丁堡地区的拟南芥种群在遗传组成和行为方面出乎意料地多样化。其中一些变化可能与适应性有关——来自高海拔地区的植物似乎在基因上决定了发芽更快，但在一年中开花更晚，这表明它们可能适应了晚一点的春天，但不适应可能影响低海拔地区植物的夏季降雨不足。相比之下，我们发现来自同一生境的植物有可能以非常不同的速度生长，尽管我们还不知道为什么这种差异可能对植物有利。为了理解这种自然变异的基础，我们将测试已知的控制开花时间的基因是否对我们在爱丁堡周围看到的差异负责，并由此研究自然选择在高海拔地区开花晚是否有利于某些基因。由于我们对基因控制植物生长速度的方式知之甚少，因此我们将利用不同野生植物之间的杂交品种，找出导致爱丁堡地区生长速度差异的基因。对于这些基因中的至少一个，我们将确定其DNA序列，并研究序列的变化如何导致植物生长速度的变化。然后，我们将研究这些基因的选择是否可以解释生长在同一地点的植物之间生长速度的差异。最后，我们将种植来自不同地点的植物，以及具有不同性状组合的杂交植物，在不同海拔的栖息地，以找到哪种基因和性状组合在每种环境中最有利。这将表明我们在自然界中看到的变异模式是否可能是由于自然选择而产生的。了解生物体适应不同环境的原因对于理解进化过程和预测环境变化将如何影响作物和自然植物群落的成功非常重要。这与在爱丁堡附近种植拟南芥特别相关，因为该物种接近其最北端的极限，因此可以测试非自然恶劣环境对其成功的影响（例如，在比通常发现的海拔更高的地方种植）。确定哪些基因控制植物生长，以及它们的DNA变异如何促进生长，与作物育种进一步相关。

项目成果

The scale of population structure in Arabidopsis thaliana.

• DOI: 10.1371/journal.pgen.1000843
• 发表时间: 2010-02-12
• 期刊: PLoS genetics
• 影响因子: 4.5
• 作者: Platt A;Horton M;Huang YS;Li Y;Anastasio AE;Mulyati NW;Agren J;Bossdorf O;Byers D;Donohue K;Dunning M;Holub EB;Hudson A;Le Corre V;Loudet O;Roux F;Warthmann N;Weigel D;Rivero L;Scholl R;Nordborg M;Bergelson J;Borevitz JO
• 通讯作者: Borevitz JO