Liu Huaiqiang, Li Frank Yonghong, Liu Jiayue, Shi Chunjun, Tang Kuanyan, Yang Qianhui, Liu Yu, Fu Qiang, Gao Xiaotian, Wang Ning, Guo Wei
Ministry of Education Key Laboratory of Ecology and Resource Use on the Mongolian Plateau and Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot, China.
Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education of China, Hohhot, China.
Front Microbiol. 2023 Mar 16;14:1113157. doi: 10.3389/fmicb.2023.1113157. eCollection 2023.
The decoupling of microbial functional and taxonomic components refers to the phenomenon that a drastic change in microbial taxonomic composition leads to no or only a gentle change in functional composition. Although many studies have identified this phenomenon, the mechanisms underlying it are still unclear. Here we demonstrate, using metagenomics data from a steppe grassland soil under different grazing and phosphorus addition treatments, that there is no "decoupling" in the variation of taxonomic and metabolic functional composition of the microbial community within functional groups at species level. In contrast, the high consistency and complementarity between the abundance and functional gene diversity of two dominant species made metabolic functions unaffected by grazing and phosphorus addition. This complementarity between the two dominant species shapes a bistability pattern that differs from functional redundancy in that only two species cannot form observable redundancy in a large microbial community. In other words, the "monopoly" of metabolic functions by the two most abundant species leads to the disappearance of functional redundancy. Our findings imply that for soil microbial communities, the impact of species identity on metabolic functions is much greater than that of species diversity, and it is more important to monitor the dynamics of key dominant microorganisms for accurately predicting the changes in the metabolic functions of the ecosystems.
微生物功能和分类学组成的解耦是指微生物分类学组成发生剧烈变化，但功能组成却没有变化或仅发生轻微变化的现象。尽管许多研究已经识别出了这一现象，但其背后的机制仍不清楚。在这里，我们利用来自不同放牧和添加磷处理下的草原土壤的宏基因组数据证明，在物种水平的功能组内，微生物群落的分类学和代谢功能组成的变化不存在“解耦”。相反，两个优势物种的丰度和功能基因多样性之间的高度一致性和互补性使得代谢功能不受放牧和添加磷的影响。这两个优势物种之间的这种互补性形成了一种双稳态模式，这种模式不同于功能冗余，因为在一个大型微生物群落中，仅两个物种无法形成可观察到的冗余。换句话说，两个最丰富物种对代谢功能的“垄断”导致了功能冗余的消失。我们的研究结果表明，对于土壤微生物群落而言，物种身份对代谢功能的影响远大于物种多样性，监测关键优势微生物的动态对于准确预测生态系统代谢功能的变化更为重要。
