Selective transport of plant root-associated bacterial populations in agricultural soils upon snowmelt
Selective transport of plant root-associated bacterial populations in agricultural soils upon snowmelt
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DOI：
10.1016/j.soilbio.2013.10.040
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发表时间：
2014-02-01
影响因子：
9.7
通讯作者：
Totsche, Kai Uwe
中科院分区：
文献类型：
--
作者：
Dibbern, Doerte;Schmalwasser, Andreas;Totsche, Kai Uwe
植物将丰富的碳引入土壤，在那里被矿化和隔离。引入到表层土壤中的新鲜有机碳的比例可以在大雨或融雪后通过事件驱动的运输重新定位到更深的土壤层，甚至到地下水中。据推测，这一流量的一个显着的部分涉及生物胶体和可能的微生物生物量本身。然而，这种运输微生物的性质，它们的起源和它们的动员机制仍然知之甚少。在这里，我们提供的主要证据表明，特定的微生物种群出口从表层土壤渗漏事件。在一个实验玉米田，我们分析了流动的细菌群落收集在渗水后，直接在冬季融雪在不同深度（35和65厘米）的组成，并将其与相应的散装土壤微生物群。使用T-RFLP指纹图谱和pyrotag测序，我们发现，大多数成员的β-变形菌（嗜甲基菌科，Oxalobacteraceae，丛枝菌科），α-变形菌（鞘氨醇单胞菌科，慢生根瘤菌科），γ-变形菌（军团菌科）和拟杆菌（鞘氨醇杆菌科）被动员，所有特征类群的根面。这突出了优先流沿着根通道的微生物的垂直动员和运输的重要性。虽然估计的细菌生物量碳的定量通量似乎较低，我们的研究允许更好地了解表土，底土和地下水微生物群之间的联系，以及土壤隔间之间的碳通量。(C)2013爱思唯尔有限公司保留所有权利。
Plants introduce abundant carbon into soils, where it is mineralised and sequestered. Proportions of this fresh organic carbon introduced to top soils can be relocated to deeper soil layers and even to groundwater by event-driven transport upon heavy rainfalls or after snowmelt. It is assumed that a significant fraction of this flux involves biocolloids and possibly microbial biomass itself. However, the nature of such transported microbes, their origin and the mechanisms of their mobilisation are still poorly understood. Here, we provide primary evidence that specific microbial populations are exported from top soils upon seepage events. At an experimental maize field, we have analysed the composition of mobilised bacterial communities collected in seepage water directly after snowmelt in winter at different depths (35 and 65 cm), and compared them to the corresponding bulk soil microbiota. Using T-RFLP fingerprinting and pyrotag sequencing, we reveal that mostly members of the Betaproteobacteria (Methylophilaceae, Oxalobacteraceae, Comamonadaceae), the Alphaproteobacteria (Sphingomonadaceae, Bradyrhizobiaceae), the Gammaproteobacteria (Legionellaceae) and the Bacteroidetes (Sphingobacteriaceae) were mobilised, all characteristic taxa for the rhizoplane. This highlights the importance of preferential flow along root channels for the vertical mobilisation and transport of microbes. Although the estimated quantitative fluxes of bacterial biomass carbon appeared low, our study allows for an improved understanding of the links between top soil, subsoil, and groundwater microbiota, as well as carbon fluxes between soil compartments. (C) 2013 Elsevier Ltd. All rights reserved.