Guan Xiangyu, Wang Jinfeng, Zhao Hui, Wang Jianjun, Luo Ximing, Liu Fei, Zhao Fangqing
Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083, China.
BMC Genomics. 2013 Nov 22;14(1):820. doi: 10.1186/1471-2164-14-820.
As the largest low-latitude permafrost region, the Tibetan Plateau (TP) is an important part of the earth's terrestrial ecosystem and one of the most vulnerable areas to climate change and human activities. However, to the best of our knowledge, the bacterial communities in TP soils and their roles in biogeochemical cycles remain limited.
In this study, we report the bacterial community structure and function as well as their correlation with environmental factors in TP major ecosystems (farmland, alpine meadow and oligosaline lake) by using metagenomic approaches. Compared with other soil samples in various environments, TP soils share a core set of microorganisms with a distinct abundance and composition. Among TP soil samples, the taxonomic and functional composition of bacterial communities among the upper (3-5 cm) and lower (18-20 cm) soils of farmland sites were highly similar, whereas the dissimilarities within alpine meadow samples were significantly greater than among farmland samples. A similar pattern was observed in elements cycles and pathways associated with adaption to environment and land use types. Canonical correlation analysis revealed that the bacterial communities in most of farmland and alpine meadow soil samples were also significantly correlated with geogenic variables. Specifically, the root-nodule bacteria are negatively correlated with the soil moisture and pH, while Thiobacillus associated with sulfur cycles show potential responses to low temperature and intense UV radiation.
These findings indicate that the bacterial community structure and functions in TP soils were influenced by both human activities and soil environmental properties, and that the bacterial communities appeared to be more homogenized in the farmland soils compared with pristine alpine meadows.
作为最大的低纬度冻土区，青藏高原是地球陆地生态系统的重要组成部分，也是最易受气候变化和人类活动影响的地区之一。然而，据我们所知，青藏高原土壤中的细菌群落及其在生物地球化学循环中的作用仍然有限。
在本研究中，我们通过宏基因组学方法报告了青藏高原主要生态系统（农田、高寒草甸和微咸湖）中细菌群落的结构和功能及其与环境因素的相关性。与各种环境中的其他土壤样本相比，青藏高原土壤拥有一组核心微生物，其丰度和组成各不相同。在青藏高原土壤样本中，农田上层（3-5厘米）和下层（18-20厘米）土壤中细菌群落的分类和功能组成高度相似，而高寒草甸样本中的差异明显大于农田样本。在与环境适应和土地利用类型相关的元素循环和途径中也观察到类似模式。典型相关分析表明，大多数农田和高寒草甸土壤样本中的细菌群落也与地质成因变量显著相关。具体而言，根瘤菌与土壤湿度和pH呈负相关，而与硫循环相关的硫杆菌对低温和强烈紫外线辐射表现出潜在响应。
这些发现表明，青藏高原土壤中的细菌群落结构和功能受人类活动和土壤环境特性的影响，并且与原始高寒草甸相比，农田土壤中的细菌群落似乎更加同质化。
