Zhao Kang, Kong Weidong, Khan Ajmal, Liu Jinbo, Guo Guangxia, Muhanmmad Said, Zhang Xianzhou, Dong Xiaobin
Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Building 3, Courtyard 16, Lincui Road, Chaoyang District, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100101, China.
Appl Microbiol Biotechnol. 2017 Sep;101(18):7065-7074. doi: 10.1007/s00253-017-8435-x. Epub 2017 Aug 3.
Unraveling elevational diversity patterns of plants and animals has long been attracting scientific interests. However, whether soil microorganisms exhibit similar elevational patterns remains largely less explored, especially for functional microbial communities, such as ammonia oxidizers. Here, we investigated the diversity and distribution pattern of ammonia-oxidizing archaea (AOA) in meadow soils along an elevation gradient from 4400 m to the grassline at 5100 m on the Tibetan Plateau using terminal restriction fragment length polymorphism (T-RFLP) and sequencing methods by targeting amoA gene. Increasing elevations led to lower soil temperature and pH, but higher nutrients and water content. The results showed that AOA diversity and evenness monotonically increased with elevation, while richness was relatively stable. The increase of diversity and evenness was attributed to the growth inhibition of warm-adapted AOA phylotypes by lower temperature and the growth facilitation of cold-adapted AOA phylotypes by richer nutrients at higher elevations. Low temperature thus played an important role in the AOA growth and niche separation. The AOA community variation was explained by the combined effect of all soil properties (32.6%), and 8.1% of the total variation was individually explained by soil pH. The total AOA abundance decreased, whereas soil potential nitrification rate (PNR) increased with increasing elevations. Soil PNR positively correlated with the abundance of cold-adapted AOA phylotypes. Our findings suggest that low temperature plays an important role in AOA elevational diversity pattern and niche separation, rising the negative effects of warming on AOA diversity and soil nitrification process in the Tibetan region.
长期以来，揭示动植物的海拔多样性模式一直吸引着科学界的关注。然而，土壤微生物是否呈现类似的海拔模式在很大程度上仍未得到充分探索，尤其是对于功能性微生物群落，如氨氧化菌。在此，我们利用末端限制性片段长度多态性（T-RFLP）和测序方法，通过靶向amoA基因，研究了青藏高原上海拔从4400米到5100米草线的草甸土壤中氨氧化古菌（AOA）的多样性和分布模式。海拔升高导致土壤温度和pH值降低，但养分和含水量升高。结果表明，AOA的多样性和均匀度随海拔升高单调增加，而丰富度相对稳定。多样性和均匀度的增加归因于较低温度对适应温暖环境的AOA系统型的生长抑制，以及较高海拔处更丰富的养分对适应寒冷环境的AOA系统型的生长促进。因此，低温在AOA的生长和生态位分离中起着重要作用。AOA群落变异由所有土壤性质的综合效应解释（32.6%），总变异的8.1%由土壤pH单独解释。随着海拔升高，AOA的总丰度下降，而土壤潜在硝化速率（PNR）增加。土壤PNR与适应寒冷环境的AOA系统型的丰度呈正相关。我们的研究结果表明，低温在AOA的海拔多样性模式和生态位分离中起着重要作用，这凸显了变暖对青藏高原地区AOA多样性和土壤硝化过程的负面影响。
