Fatty acid methyl ester (FAME) profiling for characterizing microbial community composition typically is conducted via phospholipid fatty acid (PLFA) or ester‐linked fatty acid methyl ester (EL‐FAME) methods. As soil health assessments aim to be utilized across the nation and globe, the robust measurement and interpretation of microbial communities across a range of soils and environments will be necessary. This study compared PLFA and EL‐FAME methods for detecting and interpreting profiles of microbial community composition in croplands across a wide geographic area using a total of 172 soil samples from 14 states representing a wide range of soil properties. Overall, PLFA and EL‐FAME provided comparable biomarkers in terms of microbial community composition. The Spearman's Rank correlation test showed positive correlations (r = 0.37–0.71) between PLFA and EL‐FAME methods for absolute abundance of total FAME and individual microbial groups including fungi (saprophytic fungi [SF], arbuscular mycorrhizal fungi [AMF], and general fungi [F]) and all bacterial groups (Gram positive [GMP], Gram negative [GMN], and Actinobacteria). In both methods, a common set of fatty acids were influential in differentiating samples. The main differences in biomarker abundances between the two methods were that fungal and Actinobacteria biomarkers (e.g., 16:1ω5c [AMF], 18:1ω9c [F], 18:3ω6c [F], and 10Me16:0 [Actinobacteria]) were more abundant or critical in EL‐FAME profiling (large variation among soil samples and sensitive to soil properties), but bacterial biomarkers such as i15:0 (GMP), 16:1ω7c (GMN), 18:1ω7c (GMN), and cy19:0ω7c (GMN) were more dominant and responsive to soil properties in PLFA profiling. The practical advantages of EL‐FAME are lower cost and simpler methodology. Although both methods produced similar microbial profile abundances for important microbial markers, PLFA was more sensitive to the wide range of soil chemical properties in this sample set including pH, clay content, soil organic matter, and active carbon.

中文翻译：

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脂肪酸甲酯分析方法（PLFA和EL‐FAME）作为土壤健康指标的比较

用于表征微生物群落组成的脂肪酸甲酯（FAME）分析通常通过磷脂脂肪酸（PLFA）或酯键联脂肪酸甲酯（EL-FAME）方法进行。由于土壤健康评估的目标是在全国和全球范围内使用，因此有必要对各种土壤和环境中的微生物群落进行有效的测量和解释。这项研究使用了来自14个州的172种土壤样品，代表了广泛的土壤特性，比较了PLFA和EL‐FAME方法在广泛的地理区域内检测和解释农田中微生物群落组成的概况。总体而言，就微生物群落组成而言，PLFA和EL‐FAME提供了可比的生物标志物。Spearman秩相关检验显示出正相关（PLFA和EL‐FAME方法之间的绝对丰度和单个微生物组（包括真菌（腐生真菌[SF]，丛枝菌根真菌[AMF]和普通真菌[F]））和所有细菌组的绝对丰度，r  = 0.37–0.71） （革兰氏阳性[GMP]，革兰氏阴性[GMN]和放线杆菌）。在这两种方法中，一组常见的脂肪酸对区分样品都有影响。在生物标记丰度的两种方法之间的主要的区别在于真菌和放线菌的生物标志物（例如。，16：1ω5c[AMF]，18：1ω9c[F]，18：3ω6c[F]，和10Me16：0 [放线菌]）分别为在EL‐FAME分析中更为丰富或关键（土壤样品之间差异很大且对土壤特性敏感），但细菌生物标记物如i15：0（GMP），16：1ω7c（GMN），18：1ω7c（GMN）和cy19：0ω7c（GMN）在PLFA分析中更占优势，并且对土壤特性有反应。EL‐FAME的实际优势是成本更低，方法更简单。尽管两种方法对于重要的微生物标记物都产生了相似的微生物谱丰度，但是PLFA对此样品集中的多种土壤化学特性（包括pH值，粘土含量，土壤有机质和活性炭）更加敏感。