Yongxing Cui1, Linchuan Fang2, Xiaobin Guo3, Xia Wang1, Yunqiang Wang4, Pengfei Li1, Yanjiang Zhang5, Xingchang Zhang6. 1. 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. 2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, PR China. Electronic address: flinc629@hotmail.com. 3. Agriculture Production and Research Division, Department of Fisheries and Land Resources, Government of Newfoundland and Labrador, Corner Brook, NL A2H 6J8, Canada. 4. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, Shaanxi 710061, PR China. 5. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling 712100, PR China. 6. 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.
Abstract
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 NH4+-N strongly affected bacterial communities, whereas NO3--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.
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 expn>lored the association of microbial communities with nutrient limitation via high-throughpn>ut sequencing. Threshold elemental ratios (TER) indicated that the microbial communities were strongly limited by n>an class="Chemical">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 NH4+-N strongly affected bacterial communities, whereas NO3--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.