State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, PR China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, PR China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, PR China.
Sci Total Environ. 2018 Nov 15;642:45-55. doi: 10.1016/j.scitotenv.2018.06.033. Epub 2018 Jun 18.
Soil microorganisms are crucial to indicate ecosystem functions of terrestrial ecosystems. However, the responses of microbial communities to soil nutrient limitation in desert-grassland are still poorly understood. Hence, we investigated soil microbial community structures and metabolic characteristics in a desert-grassland ecological transition zone from the northern Loess Plateau, China, and explored the association of microbial communities with nutrient limitation via high-throughput sequencing. Threshold elemental ratios (TER) indicated that the microbial communities were strongly limited by nitrogen (N) under A. ordosica and P. tabuliformis communities. The phosphorus (P) limitation of microbial communities was observed in the aeolian sandy soil. The results imply that soil microbial communities had strong nutrient competition for N and P with aboveground vegetation in arid and oligotrophic ecosystems. The LEfSe and linear regression analysis revealed that the microbial taxa of Micrococcales, Micrococcaceae and Herpotrichiellaceae were significantly correlated with microbial N limitation. The Thermoleophilia taxa were significantly correlated with microbial P limitation. These biomarkers related to microbial nutrient limitation could be considered as the key microbial taxa to shape microbial communities and functions. Furthermore, N form had different effects on microbial communities, which NH-N strongly affected bacterial communities, whereas NO-N had a significant influence on fungal communities. The different responses indicate that soil microorganisms had corresponding nutrient preferences for bacterial and fungal communities, which might alleviate the nutrient limitations and environmental stress. This study provided important insights on microbial community structures linking to community functions and on the mechanisms governing microbial N and P limitation in arid land ecosystems.
土壤微生物对于指示陆地生态系统的生态功能至关重要。然而，对于荒漠草原土壤微生物群落对土壤养分限制的响应仍知之甚少。因此，我们研究了来自中国黄土高原北部荒漠草原生态过渡带的土壤微生物群落结构和代谢特征，并通过高通量测序探讨了微生物群落与养分限制的关联。阈元素比（TER）表明，在 A. ordosica 和 P. tabuliformis 群落中，微生物群落受到氮（N）的强烈限制。在风成沙土壤中观察到微生物群落的磷（P）限制。这些结果表明，在干旱和贫营养的生态系统中，土壤微生物群落与地上植被对 N 和 P 具有强烈的养分竞争。LEfSe 和线性回归分析表明，Micrococcales、Micrococcaceae 和 Herpotrichiellaceae 的微生物类群与微生物 N 限制显著相关。Thermoleophilia 类群与微生物 P 限制显著相关。这些与微生物养分限制相关的生物标志物可被视为塑造微生物群落和功能的关键微生物类群。此外，N 形态对微生物群落有不同的影响，NH-N 强烈影响细菌群落，而 NO-N 对真菌群落有显著影响。不同的响应表明，土壤微生物对细菌和真菌群落具有相应的养分偏好，这可能缓解养分限制和环境压力。本研究为微生物群落结构与群落功能以及干旱地区生态系统中微生物 N 和 P 限制的机制提供了重要的见解。
