Comparison of Whole-Cell Fatty Acid (MIDI) or Phospholipid Fatty Acid (PLFA) Extractants as Biomarkers to Profile Soil Microbial Communities
Comparison of Whole-Cell Fatty Acid (MIDI) or Phospholipid Fatty Acid (PLFA) Extractants as Biomarkers to Profile Soil Microbial Communities
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DOI：
10.1007/s00248-013-0195-2
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发表时间：
2013-07-01
影响因子：
3.6
通讯作者：
Dick, Richard P.
中科院分区：
文献类型：
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作者：
Fernandes, Marcelo F.;Saxena, Jyotisna;Dick, Richard P.
使用脂肪酸（FA）生物标志物对土壤上的微生物群落进行分析的全细胞脂质提取通常使用与磷脂脂肪酸（PLFA）或微生物鉴定公司（Microbial Identification Inc.）（三）方法。这些萃取剂具有非常不同的化学和脂质分离程序，但往往表现出类似的能力，从不同的管理和植被系统区分土壤。然而，通过这两种方法提取的FA的确切套件的机制和化学性质知之甚少。因此，我们的目标是定性和定量比较的微生物群落的变化，由于土壤类型或管理的微生物分析方法，用于检测。从俄勒冈州广泛的土壤类型中收集了29个土壤样品，并通过气相色谱（GC）和GC-质谱法分析了每种方法提取的脂肪酸。不像PLFA的配置文件，这是高度相关的微生物脂肪酸，整体MIDI-FA配置文件是高度相关的植物源性脂肪酸。植物相关化合物的定量相关的颗粒有机物（POM）和定性相关的常设植被采样。这些脂肪酸呈负相关的呼吸速率标准化POM（呼吸（POM）），这增加了系统下更密集的管理。MIDI-FA与PLFA的比值与总有机碳（TOC）呈显著负相关。当测试用于萃取程序的试剂从具有高有机质的土壤中有限地回收MIDI-FA时，MIDI-FA微生物特征的回收率随着土壤与萃取剂的比率的增加而急剧下降。因此，在解释由于微生物群落的变化而引起的FA谱变化时，应非常谨慎地使用微生物计数法。
The whole-cell lipid extraction to profile microbial communities on soils using fatty acid (FA) biomarkers is commonly done with the two extractants associated with the phospholipid fatty acid (PLFA) or Microbial IDentification Inc. (MIDI) methods. These extractants have very different chemistry and lipid separation procedures, but often shown a similar ability to discriminate soils from various management and vegetation systems. However, the mechanism and the chemistry of the exact suite of FAs extracted by these two methods are poorly understood. Therefore, the objective was to qualitatively and quantitatively compare the MIDI and PLFA microbial profiling methods for detecting microbial community shifts due to soil type or management. Twenty-nine soil samples were collected from a wide range of soil types across Oregon and extracted FAs by each method were analyzed by gas chromatography (GC) and GC-mass spectrometry. Unlike PLFA profiles, which were highly related to microbial FAs, the overall MIDI-FA profiles were highly related to the plant-derived FAs. Plant-associated compounds were quantitatively related to particulate organic matter (POM) and qualitatively related to the standing vegetation at sampling. These FAs were negatively correlated to respiration rate normalized to POM (Resp(POM)), which increased in systems under more intensive management. A strong negative correlation was found between MIDI-FA to PLFA ratios and total organic carbon (TOC). When the reagents used in MIDI procedure were tested for the limited recovery of MIDI-FAs from soil with high organic matter, the recovery of MIDI-FA microbial signatures sharply decreased with increasing ratios of soil to extractant. Hence, the MIDI method should be used with great caution for interpreting changes in FA profiles due to shifts in microbial communities.