Genomics of variation in nitrogen fixation activity in a population of the thermophilic cyanobacterium Mastigocladus laminosus
Genomics of variation in nitrogen fixation activity in a population of the thermophilic cyanobacterium Mastigocladus laminosus
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DOI：
10.1038/ismej.2016.105
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发表时间：
2017-01-01
期刊：
影响因子：
11
通讯作者：
Miller, Scott R.
中科院分区：
文献类型：
--
作者：
Hutchins, Patrick R.;Miller, Scott R.
表型性状的变化，有助于健身影响人口的进化反应和生态系统功能的影响，环境变化后，但其数量和性质很少知道。在这里，我们调查了氮（N）固定活性及其遗传基础的随机样本的实验室菌株的蓝藻Mastigocladus laminosus从一个N有限的，地热影响流在黄石国家公园。在线性混合效应模型中，温度和菌株间的遗传差异是解释活性变化的最重要因素。固氮活性不同的菌株组之间的遗传分歧的全基因组分析显示，很少有位点与这些表型差异密切相关。值得注意的是，硫酸盐同化基因apsK中的一个非同义多态性解释了高温下活性变化的25%以上。我们进一步确定了等位基因变异的多个终端细胞色素氧化酶的固氮的不同方面的作用。此外，固定最多N的菌株的基因组在组氨酸激酶基因中含有无义突变，预计会破坏正常的蛋白质功能，并可能导致转录重新连接。这项研究说明了如何采取互补的方法来连接表型和基因型可以告知我们的微生物种群多样性的理解。
Variation in phenotypic traits that contribute to fitness influences a population's evolutionary response and its impact on ecosystem function following environmental change, yet its amount and nature are rarely known. Here, we investigated variation in nitrogen (N) fixation activity and its genetic basis for a random sample of laboratory strains of the cyanobacterium Mastigocladus laminosus from a N-limited, geothermally influenced stream in Yellowstone National Park. In a linear mixed-effects model, temperature and genetic differences among strains were the most important factors explaining variation in activity. Genome-wide analyses of genetic divergence between groups of strains that varied in N fixation activity revealed that few loci were strongly associated with these phenotypic differences. Notably, a single nonsynonymous polymorphism in the sulfate assimilation gene apsK explained >25% of the variation in activity at high temperature. We further identified a role for allelic variation of multiple terminal cytochrome oxidases for different aspects of N fixation. In addition, genomes of strains that fixed the most N overall contained a nonsense mutation in a histidine kinase gene that is expected to disrupt normal protein function and may result in transcriptional rewiring. This study illustrates how taking complementary approaches to link phenotype and genotype can inform our understanding of microbial population diversity.