Jiamin Xiao, Haonan Wu, Chao Xu, Yajun Hu, Zhiwen Xu, Dongxu Zhang, Abo Li, Xiaomeng Wei, Tida Ge, Gehong Wei
State Key Laboratory for Crop Stress Resistance and High-Efficiency Production and Shaanxi Key Laboratory of Agricultural and Environment Microbiology, College of Life Sciences, Northwest A&F University, Xianyang, China.
College of Natural Resources and Environment, Northwest A&F University, Xianyang, China.
Front Microbiol. 2025 Feb 19;16:1541460. doi: 10.3389/fmicb.2025.1541460. eCollection 2025.
Aerobic bacteria extensively drive the carbon cycle in soil owing to their vigorous respiration; however, their geographical distribution and mechanisms remain poorly understood. The citric acid synthetase-encoding gene (), which encodes the key enzyme in the tricarboxylic acid cycle of aerobic respiration, was used as a marker gene to investigate the geographical distribution of aerobic bacteria in Chinese agricultural fields. The abundance and diversity of -harboring bacteria changed unimodally as the latitude increased, with peak values at middle latitudes, where the dominant species showed the lowest relative abundance. Despite the different water management practices, our data found little difference in the abundance, diversity, or relative abundance of the dominant species of -harboring bacteria between paddy and upland soils on a large scale, which was significantly affected by the soil type (black, fluvo-aquic, and red), which can be defined by the soil texture. Linear regression and random forest model analyses indicated that soil texture strongly regulated the community of -harboring bacteria, particularly the abundance of this functional guild. Generally, less abundant and diverse -harboring bacteria were observed in soils with higher clay content. We identified biomarkers in the different soil types using linear discriminant analysis effect size analysis. The results suggest a significant correlation between soil texture and most of these biomarkers. Additionally, the biomarkers in black soil were mainly -strategists, which include , and , were positively correlated with soil organic carbon content. In contrast, the biomarkers in fluvo-aquic soil were generally -strategists, such as , and were negatively correlated with soil organic carbon content. These different biomarkers likely play distinct roles in soil carbon sequestration. This study provides foundational insights into the role of aerobic bacteria in soil and enhances our understanding of microbial contributions to the biogeochemical cycle of carbon.
需氧细菌因其旺盛的呼吸作用而广泛推动土壤中的碳循环；然而，它们的地理分布和机制仍知之甚少。柠檬酸合成酶编码基因（），该基因编码需氧呼吸三羧酸循环中的关键酶，被用作标记基因来研究中国农田中需氧细菌的地理分布。随着纬度增加，携带该基因的细菌的丰度和多样性呈单峰变化，在中纬度地区达到峰值，而优势物种的相对丰度最低。尽管有不同的水分管理措施，但我们的数据发现，从大规模来看，稻田和旱地土壤中携带该基因的细菌的优势物种在丰度、多样性或相对丰度上差异不大，而土壤类型（黑土、潮土和红壤）对其有显著影响，土壤类型可由土壤质地来定义。线性回归和随机森林模型分析表明，土壤质地强烈调节携带该基因的细菌群落，特别是这一功能类群的丰度。一般来说，在粘土含量较高的土壤中观察到携带该基因的细菌丰度较低且多样性较少。我们使用线性判别分析效应大小分析确定了不同土壤类型中的生物标志物。结果表明土壤质地与这些生物标志物中的大多数之间存在显著相关性。此外，黑土中的生物标志物主要是r-策略者，包括 、 和 ，它们与土壤有机碳含量呈正相关。相比之下，潮土中的生物标志物一般是K-策略者，如 、 和 ，它们与土壤有机碳含量呈负相关。这些不同的生物标志物可能在土壤碳固存中发挥不同作用。本研究为需氧细菌在土壤中的作用提供了基础见解，并增强了我们对微生物对碳生物地球化学循环贡献的理解。
