Dimensions: Collaborative Research: Genome structure and adaptive evolution in peatmosses (Sphagnum): ecosystem engineers

蓝茅属植物由分布在世界各地的300多种植物组成。在北半球的北部，它们主导着湿地，形成了广阔的泥炭地，孕育着各种各样的微生物、其他植物和动物。由于泥炭（部分分解的植物物质）的积累，这些泥炭地对区域水运动模式以及大气氮、二氧化碳和甲烷的全球循环产生了深远的影响。据估计，地球上近三分之一的土壤碳被束缚在泥炭地，尽管这些栖息地只占陆地面积的10%左右。本研究的目的是为了更好地理解DNA序列变异、植物性状和生态功能之间的联系。本研究提供了一个独特的机会，将基因组成和变异与这些基因编码的植物性状联系起来，并研究这些植物性状如何影响生态系统功能。本科生、研究生和博士后研究人员将在不同的基因组、进化、计算和生态方法和分析方面进行培训，包括合作机构之间的实验室交流。研究结果将通过实地课程和一个可公开查阅的关于泥炭层的图文并茂的联机数据库向公众广泛传播。本研究整合了广泛分布的Sphagnum物种的系统发育、普通花园实验和全属比较基因组研究，以了解物种内发生的适应过程如何扩大并解释该属在全球范围内的多样化。本研究将对代表该属全球范围的96个泥鳅种进行全基因组DNA序列的组装。这些数据将用于重建物种之间的系统发育关系，并评估全属基因组变异。对这些数据的分析将测试系统发育模式、分布范围、生态广度和生态重要表型性状变异之间的相关性。麦哲伦（Sphagnum magellanicum）分布于北极至热带地区，在纬度梯度上采集，在实验条件下生长，评估其光合作用对昼夜长度和温度等环境因子的响应，以及种群在生理响应中的分化。实验植物的基因表达响应将通过RNA测序来测量，以更好地了解局部生理适应的遗传基础。将对不同麦哲伦居群的全基因组DNA序列进行组装，以评估单个物种（Pan基因组结构）内基因含量的变化。将这些种群水平的数据与跨越泥炭属物种的全基因组序列数据进行比较，将确定这些基因与其他泥炭属物种共有多少。这些数据将用于测试的一个具体预测是，一个广泛分布的物种的热带植物的诱导生理反应是否已经成为热带Sphagnum物种的固定和组成部分。

Peatmosses comprise a diverse group of plants with over 300 species distributed throughout the world. In northern parts of the Northern Hemisphere, they dominate wetlands and form extensive peatlands that harbor a broad diversity of microbes, other plants, and animals. Because of the build-up of peat (partially decomposed plant material), these peatlands have profound impacts on regional patterns of water movement, and the global cycling of atmospheric nitrogen, carbon dioxide, and methane. It is estimated that almost one third of the earth's soil carbon is bound up in peatlands even though these habitats account for only about 10% of the land surface area. The goals of this research are to use peatmosses as a model to better understand the connections between DNA sequence variation, plant traits, and ecological function. This research provides a unique opportunity to connect gene composition and variation to the plant traits encoded by those genes, and investigate how these plant traits affect ecosystem function. Undergraduates, graduate students and post-doctoral researchers will be trained in diverse genomic, evolutionary, computational, and ecological methods and analysis, including laboratory exchanges among the collaborating institutions. Results will be disseminated broadly to the public via field courses and an illustrated publically accessible, online database about peatmosses. This research integrates broad-level phylogenetics, common garden experiments of a widely-distributed Sphagnum species, and genus-wide comparative genomic studies to understand how adaptive processes occurring within species scale up to and explain diversification of the genus on a worldwide scale. Whole genome DNA sequences will be assembled for 96 Sphagnum species representing the worldwide range of the genus. These data will then be used to reconstruct phylogenetic relationships among species and assess genus-wide genomic variation. Analyses of these data will then test for correlations among phylogenetic patterns, distributional range, ecological breadth, and variation in ecologically important phenotypic traits. Plants of Sphagnum magellanicum, which occurs from arctic to tropical regions, will be collected across a latitudinal gradient and grown under experimental conditions to assess photosynthetic responses to environmental factors including day length and temperature, and population differentiation in physiological response. Gene expression responses in experimental plants will be measured using RNA sequencing to better understand the genetic basis of local physiological adaptation. Whole genome DNA sequences of different S. magellanicum populations will be assembled to assess variation in gene content within a single species (Pan genome structure). Comparing these population-level data with whole genome sequence data from species spanning the Sphagnum genus will identify how many of these genes are shared with other peatmoss species. One specific prediction these data will be used to test is whether inducible physiological responses in tropical plants of a widespread species have become fixed and constitutive in tropical Sphagnum species.