Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843-2474, USA.
ISME J. 2010 Jun;4(6):829-38. doi: 10.1038/ismej.2010.3. Epub 2010 Feb 4.
Studies of hypersaline ecosystems often yield novel organisms and contribute to our understanding of extreme environments. Soils and sediments from La Sal del Rey, a previously uncharacterized, hypersaline lake located in southern Texas, USA, were surveyed to characterize the structure and diversity of their microbial communities. Samples were collected along a transect that spanned vegetated uplands, exposed lakebed sediments, and water-logged locations, capturing a wide range of environments and physical and chemical gradients. Community quantitative PCR (qPCR) was used in combination with tag-encoded pyrosequencing, 16S rRNA gene cloning, and Sanger sequencing to characterize the lake's soil and sediment microbial communities. Further, we used multivariate statistics to identify the relationships shared between sequence diversity and heterogeneity in the soil environment. The overall microbial communities were surprisingly diverse, harboring a wide variety of taxa, and sharing significant correlations with site water content, phosphorus and total organic carbon concentrations, and pH. Some individual populations, especially of Archaea, also correlated with sodium concentration and electrical conductivity salinity. Across the transect, Bacteria were numerically dominant relative to Archaea, and among them, three phyla--the Proteobacteria, Bacteroidetes, and Firmicutes--accounted for the majority of taxa detected. Although these taxa were detected with similar abundances to those described in other hypersaline ecosystems, the greater depth of sequencing achieved here resulted in the detection of taxa not described previously in hypersaline sediments. The results of this study provide new information regarding a previously uncharacterized ecosystem and show the value of high-throughput sequencing in the study of complex ecosystems.
对高盐度生态系统的研究经常会产生新的生物，并有助于我们了解极端环境。对位于美国德克萨斯州南部一个以前未被描述的高盐度湖泊 La Sal del Rey 的土壤和沉积物进行了调查，以描述其微生物群落的结构和多样性。样本沿着一个横跨植被高地、暴露的湖底沉积物和水浸位置的剖面采集，以捕获广泛的环境和物理化学梯度。采用定量 PCR (qPCR) 结合标签编码焦磷酸测序、16S rRNA 基因克隆和 Sanger 测序来描述该湖的土壤和沉积物微生物群落。此外，我们还使用多元统计来确定序列多样性与土壤环境异质性之间的关系。总的来说，微生物群落出人意料地多样化，包含了各种各样的分类群，并与地点的含水量、磷和总有机碳浓度以及 pH 值存在显著相关性。一些个体种群，特别是古菌，也与钠离子浓度和电导率盐度相关。在整个剖面上，细菌在数量上相对于古菌占优势，其中三个门——变形菌门、拟杆菌门和厚壁菌门——占检测到的大多数分类群。尽管这些分类群的丰度与其他高盐度生态系统中描述的相似，但这里实现的高通量测序深度导致了以前在高盐沉积物中未描述的分类群的检测。这项研究的结果提供了一个以前未被描述的生态系统的新信息，并展示了高通量测序在复杂生态系统研究中的价值。
