Chair of Soil Ecology, Technische Universität München, Neuherberg, Germany.
ISME J. 2012 Sep;6(9):1763-74. doi: 10.1038/ismej.2012.17. Epub 2012 Mar 8.
Alkanes are major constituents of plant-derived waxy materials. In this study, we investigated the abundance, community structure and activity of bacteria harbouring the alkane monooxygenase gene alkB, which catalyses a major step in the pathway of aerobic alkane degradation in the litter layer, the litter-soil interface and in bulk soil at three time points during the degradation of maize and pea plant litter (2, 8 and 30 weeks) to improve our understanding about drivers for microbial performance in different soil compartments. Soil cores of different soil textures (sandy and silty) were taken from an agricultural field and incubated at constant laboratory conditions. The abundance of alkB genes and transcripts (by qPCR) as well as the community structure (by terminal restriction fragment polymorphism fingerprinting) were measured in combination with the concentrations and composition of alkanes. The results obtained indicate a clear response pattern of all investigated biotic and abiotic parameters depending on the applied litter material, the type of soil used, the time point of sampling and the soil compartment studied. As expected the distribution of alkanes of different chain length formed a steep gradient from the litter layer to the bulk soil. Mainly in the two upper soil compartments community structure and abundance patterns of alkB were driven by the applied litter type and its degradation. Surprisingly, the differences between the compartments in one soil were more pronounced than the differences between similar compartments in the two soils studied. This indicates the necessity for analysing processes in different soil compartments to improve our mechanistic understanding of the dynamics of distinct functional groups of microbes.
烷烃是植物衍生蜡质材料的主要成分。在本研究中，我们调查了在有氧烷烃降解途径中催化主要步骤的烷烃单加氧酶基因 alkB 存在的细菌的丰度、群落结构和活性，这些细菌存在于凋落物层、凋落物-土壤界面和大量土壤中，以在玉米和豌豆植物凋落物（2、8 和 30 周）降解过程中的三个时间点，以提高我们对不同土壤区室中微生物性能驱动因素的理解。从农业田地中取出不同土壤质地（沙质和粉质）的土壤芯，并在恒定的实验室条件下进行培养。通过 qPCR 测量 alkB 基因和转录物的丰度（通过 qPCR）以及群落结构（通过末端限制性片段多态性指纹图谱），同时测量烷烃的浓度和组成。所得结果表明，所有调查的生物和非生物参数都呈现出明显的响应模式，具体取决于所应用的凋落物材料、所使用的土壤类型、采样时间点和研究的土壤区室。如预期的那样，不同链长的烷烃的分布从凋落物层到大量土壤形成了一个陡峭的梯度。主要在两个上层土壤区室中，alkB 的群落结构和丰度模式受到应用凋落物类型及其降解的驱动。令人惊讶的是，一个土壤中区室之间的差异比两个研究土壤中相似区室之间的差异更为明显。这表明需要分析不同土壤区室中的过程，以提高对不同功能微生物群体动态的机制理解。
