Yu Jing, Yang Jingyi, Qu Lingrui, Huang Xiaoyi, Liu Yue, Jiang Ping, Wang Chao
Chinese Academy of Sciences, Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
ISME Commun. 2024 Dec 27;5(1):ycae173. doi: 10.1093/ismeco/ycae173. eCollection 2025 Jan.
The role of mycorrhizal associations in controlling forest soil carbon storage remains under debate. This uncertainty is potentially due to an incomplete understanding of their influence on the free-living soil microbiome and its functions. In this study, rhizosphere and non-rhizosphere soils were collected from eight arbuscular mycorrhizal (AM) and seven ectomycorrhizal (ECM) tree species in a temperate forest. We employed high-throughput sequencing and O-HO labeling to analyze the soil microbial community and carbon use efficiency (CUE), respectively. We find microbial respiration rates are higher in rhizosphere than that in non-rhizosphere soils for ECM trees, whereas microbial growth rates show no significant differences. Consequently, microbial CUE is lower in rhizosphere compared to non-rhizosphere soils for ECM trees. In addition, we find that non-rhizosphere soils from ECM trees exhibited higher CUE compared to those from AM trees. Furthermore, we observe that bacterial-fungal co-occurrence networks in ECM soils exhibit greater complexity relative to AM ones. Using random forest and structural equation modeling analyses, we find that microbial stoichiometric carbon/nitrogen imbalance and network complexity are key predictors of soil microbial CUE for AM and ECM trees, respectively. Our findings shed new light on the pivotal role of mycorrhizal associations in shaping free-living microbial communities and their metabolic characteristics in the studied soils. These insights are critical for predicting soil carbon sequestration in response to shifts in ECM and AM species within temperate forest under climate change.
菌根共生在控制森林土壤碳储存中的作用仍存在争议。这种不确定性可能是由于对其对自由生活的土壤微生物群落及其功能的影响理解不全面。在本研究中，从温带森林中的8种丛枝菌根（AM）树种和7种外生菌根（ECM）树种采集了根际和非根际土壤。我们分别采用高通量测序和¹³C-¹⁸O标记来分析土壤微生物群落和碳利用效率（CUE）。我们发现，对于ECM树种，根际土壤中的微生物呼吸速率高于非根际土壤，而微生物生长速率没有显著差异。因此，对于ECM树种，根际土壤中的微生物CUE低于非根际土壤。此外，我们发现，与AM树种的非根际土壤相比，ECM树种的非根际土壤表现出更高的CUE。此外，我们观察到，ECM土壤中的细菌-真菌共现网络相对于AM土壤表现出更大的复杂性。通过随机森林和结构方程模型分析，我们发现微生物化学计量碳/氮失衡和网络复杂性分别是AM和ECM树种土壤微生物CUE的关键预测因子。我们的研究结果为菌根共生在塑造所研究土壤中自由生活的微生物群落及其代谢特征方面的关键作用提供了新的见解。这些见解对于预测气候变化下温带森林中ECM和AM物种变化对土壤碳固存的影响至关重要。
