Active microbial RNA turnover in a grassland soil estimated using a 13CO2 spike
Active microbial RNA turnover in a grassland soil estimated using a 13CO2 spike
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DOI：
10.1016/s0038-0717(03)00117-2
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发表时间：
2003-07-01
影响因子：
9.7
通讯作者：
Manefield, M
中科院分区：
文献类型：
--
作者：
Ostle, N;Whiteley, AS;Manefield, M
根际微生物对根碳输入到土壤的初始转移和转化至关重要，但我们对这些生物体活性的理解仍然受到其有限的可培养性的限制。在这项研究中，我们结合同位素C-13示踪和分子方法来测量最近同化植物C纳入土壤微生物RNA和DNA池作为一种手段，以确定营业额的“活跃”根际社区。这需要开发一种方法，用于提取、纯化和制备小样本土壤DNA和RNA（< 5 mug C），以进行同位素分析。土壤，植物和呼吸CO2样品收集（CO2）-C-13脉冲追踪实验的间隔为20天后标记。（CO2）-C13脉冲标记后5 ~ 48 h，土壤/根系呼吸CO2中C13释放量达到峰值，136 h后出现第二个C13呼吸高峰。结果表明，土壤DNA和RNA迅速纳入最近的光合作用与最大的13 C中发现的“活跃”的微生物RNA部分反映了较高的微生物RNA周转率。脉冲衍生的C-13在RNA-C中的稀释率用于估计约20%天（-1）的微生物RNA周转，其中光降解产物衍生的C-13在RNA池中的停留时间为15-20天。这项工作的结果证实了快速转移的光合作用C输入通过土壤微生物到大气中的CO2和潜在的生物分子同位素示踪方法在土壤C的研究。(C)2003爱思唯尔科技有限公司版权所有。
Rhizosphere microbes are critical to the initial transfer and transformation of root carbon inputs to the soil but our understanding of the activity of these organisms remains constrained by their limited culturability. In this study we combined isotopic C-13 tracer and molecular approaches to measure the incorporation of recently assimilated plant C into soil microbial RNA and DNA pools as a means to determine the turnover of the 'active' rhizosphere community. This required the development of a method for the extraction, purification and preparation of small-sample soil DNA and RNA (< 5 mug C) for isotope analysis. Soil, plant and respired CO2 samples were collected from a (CO2)-C-13 pulse-chase experiment at intervals for 20 days post-labelling. The peak of C-13 release in soil/root respired CO2 came between 5 and 48 h after (CO2)-C-13 pulse-labelling and was followed by a secondary peak of soil heterotroph C-13 respiration after 136 h. Results showed that both soil DNA and RNA rapidly incorporated recent photosynthate with greatest 13C found in the 'active' microbial RNA fraction reflecting higher rates of microbial RNA turnover. The dilution rate of the pulse derived C-13 in RNA-C was used to estimate a microbial RNA turnover of approximately 20% day(-1) with a 15-20 day residence time for photosynthate derived C-13 in the RNA pool. The findings of this work confirm the rapid transfer of photosynthate C inputs through soil microorganisms to the atmosphere as CO2 and the potential of the biomolecular-isotope tracer approach in soil C research. (C) 2003 Elsevier Science Ltd. All rights reserved.