Seasonal changes in an alpine soil bacterial community in the Colorado Rocky Mountains
Seasonal changes in an alpine soil bacterial community in the Colorado Rocky Mountains
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DOI：
10.1128/aem.70.5.2867-2879.2004
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发表时间：
2004-05-01
影响因子：
4.4
通讯作者：
Schmidt, SK
中科院分区：
文献类型：
--
作者：
Lipson, DA;Schmidt, SK
暮春时节积雪融化的时期是高山生态系统的一个动态时期。庞大的冬季微生物群落开始迅速更替，向植物释放养分。以往的研究表明，科罗拉多落基山脉高山干草原的土壤微生物群落在生物量、功能、大致结构以及真菌多样性方面，在冬季和初夏之间会发生变化。然而，关于高山细菌群落的多样性以及它在这个具有重要生态意义的时期如何变化，却鲜有具体信息。我们构建了冬季、春季和夏季采集的高山土壤的16S核糖体DNA克隆文库。我们还从高山土壤中培养细菌，并在杂交实验中测量选定的培养菌株的季节性丰度。未培养的细菌群落在分类群内的多样性和丰度在季节之间发生变化。酸杆菌门在春季最为丰富。冬季群落中放线菌以及噬纤维菌 - 黄杆菌/拟杆菌（CFB）门成员的比例最高。夏季群落中疣微菌门以及β - 变形菌门的比例最高。总体而言，α - 变形菌在所有季节都同样丰富，尽管在这个群体内部可能发生了季节性变化。发现了许多来自目前未培养门类的序列，包括两个新的候选门类。培养的菌株属于α - 、β - 和γ - 变形菌、放线菌以及CFB类群。与菌株密切相关的唯一未培养序列来自冬季和春季文库。杂交实验表明，放线菌和β - 变形菌菌株在冬季最为丰富，而所测试的α - 和γ - 变形菌菌株没有显著变化。虽然培养和克隆文库通常产生不同的生物群体，但这两种方法对微生物多样性的季节性变化给出了一致的描述。
The period when the snowpack melts in late spring is a dynamic time for alpine ecosystems. The large winter microbial community begins to turn over rapidly, releasing nutrients to plants. Past studies have shown that the soil microbial community in alpine dry meadows of the Colorado Rocky Mountains changes in biomass, function, broad-level structure, and fungal diversity between winter and early summer. However, little specific information exists on the diversity of the alpine bacterial community or how it changes during this ecologically important period. We constructed clone libraries of 16S ribosomal DNA from alpine soil collected in winter, spring, and summer. We also cultivated bacteria from the alpine soil and measured the seasonal abundance of selected cultured isolates in hybridization experiments. The uncultured bacterial communities changed between seasons in diversity and abundance within taxa. The Acidobacterium division was most abundant in the spring. The winter community had the highest proportion of Actinobacteria and members of the Cytophagal Flexibacter/Bacteroides (CFB) division. The summer community had the highest proportion of the Verrucomi-crobium division and of beta-Proteobacteria. As a whole, alpha-Proteobacteria were equally abundant in all seasons, although seasonal changes may have occurred within this group. A number of sequences from currently uncultivated divisions were found, including two novel candidate divisions. The cultured isolates belonged to the alpha-, beta-, and gamma-Proteobacteria, the Actinobacteria, and the CFB groups. The only uncultured sequences that were closely related to the isolates were from winter and spring libraries. Hybridization experiments showed that actinobacterial and beta-proteobacterial isolates were most abundant during winter, while the alpha- and gamma-proteobacterial isolates tested did not vary significantly. While the cultures and clone libraries produced generally distinct groups of organisms, the two approaches gave consistent accounts of seasonal changes in microbial diversity.