Prokaryotic Diversity Changes and their Functional Interrelation to Land Use (ProFIL)

到目前为止，对细菌多样性功能相关性的研究大多局限于参与n循环的少数变形菌群和根际细菌。前一个资助期的结果显示，酸杆菌在三个探索区的土壤中占所有细菌的64%，酸杆菌的特定生理活性出乎意料地高，特别是在Schwäbische Alb的土壤中。以三个试验点的土地利用梯度为主要变量，对酸杆菌多样性的组成、生理关键性状及其功能意义进行了详细的研究。为了确定酸杆菌多样性和活性的决定因素，将对所有300个试验区的样品进行核糖体RNA基因深度测序和核糖体含量定量，并通过多元统计分析研究其与环境参数的相关性。在选定的样地研究酸杆菌群落结构的空间和短期变异的影响。通过对现有宏基因组文库的分析和对代表性菌株的鉴定，将获得有关优势土壤酸杆菌代谢特性的新信息。利用稳定同位素探测和碳捕获探测相结合的方法，研究酸杆菌在土壤碳氮循环中的功能多样性和作用。

So far, studies of the functional relevance of bacterial diversity have mostly been limited to a few groups of Proteobacteria involved in the N-cycle and to rhizosphere bacteria. Results of the preceding funding period revealed that Acidobacteria represent up to 64% of all bacteria in soils of the three exploratories and that the specific physiological activity of Acidobacteria is unexpectedly high particularly in soils from the Schwäbische Alb. Using a land use gradient across the three exploratories as the major variable, we propose to conduct a detailed study of the composition, physiological key traits and the functional implications of Acidobacteria diversity. In order to identify the determinants of Acidobacteria diversity and activity, deep sequencing of ribosomal RNA genes and quantification of the ribosome content will be conducted for samples from all 300 experimental plots and their correlation with environmental parameters will be investigated by multivariate statistical analyses. The effects of spatial and short-term temporal variability of the Acidobacteria community structure will be studied for a selected plot. Novel information on the metabolic traits of dominant soil Acidobacteria will be obtained by analyses of existing metagenomic libraries and by characterizing representative isolates. The functional diversity and role of Acidobacteria in the soil carbon and nitrogen cycles will be resolved using a combination of stable isotope probing and capture probing of incorporated carbon substrates.