Ecology Department, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America.
Department of Earth and Planetary Sciences, University of California, Davis, Davis, California, United States of America.
PLoS One. 2020 Apr 13;15(4):e0231053. doi: 10.1371/journal.pone.0231053. eCollection 2020.
Ecological theories posit that heterogeneity in environmental conditions greatly affects community structure and function. However, the degree to which ecological theory developed using plant- and animal-dominated systems applies to microbiomes is unclear. Investigating the metabolic strategies found in microbiomes are particularly informative for testing the universality of ecological theories because microorganisms have far wider metabolic capacity than plants and animals. We used metagenomic analyses to explore the relationships between the energy and physicochemical gradients in Lake Fryxell and the metabolic capacity of its benthic microbiome. Statistical analysis of the relative abundance of metabolic marker genes and gene family diversity shows that oxygenic photosynthesis, carbon fixation, and flavin-based electron bifurcation differentiate mats growing in different environmental conditions. The pattern of gene family diversity points to the likely importance of temporal environmental heterogeneity in addition to resource gradients. Overall, we found that the environmental heterogeneity of photosynthetically active radiation (PAR) and oxygen concentration ([O2]) in Lake Fryxell provide the framework by which metabolic diversity and composition of the community is structured, in accordance with its phylogenetic structure. The organization of the resulting microbial ecosystems are consistent with the maximum power principle and the species sorting model.
生态理论假设，环境条件的异质性极大地影响着群落结构和功能。然而，利用以植物和动物为主导的系统发展起来的生态理论在多大程度上适用于微生物组尚不清楚。研究微生物组中发现的代谢策略对于检验生态理论的普遍性特别有意义，因为微生物的代谢能力远远超过植物和动物。我们使用宏基因组分析来探索弗莱克斯湖的能量和物理化学梯度与底栖微生物组代谢能力之间的关系。对代谢标记基因相对丰度和基因家族多样性的统计分析表明，好氧光合作用、碳固定和黄素基电子分叉区分了在不同环境条件下生长的地衣。基因家族多样性的模式表明，除了资源梯度外，时间上的环境异质性可能也很重要。总的来说，我们发现弗莱克斯湖的光合有效辐射 (PAR) 和氧浓度 ([O2]) 的环境异质性为微生物群落的代谢多样性和组成提供了结构框架，这与它们的系统发育结构一致。由此产生的微生物生态系统的组织与最大功率原理和物种分类模型一致。
