Nunan Naoise, Singh Brajesh, Reid Eileen, Ord Brian, Papert Artemis, Squires Julie, Prosser Jim I, Wheatley Ron E, McNicol Jim, Millard Peter
Biomathematics and Statistics Scotland, Scottish Crop Research Institute, Dundee, UK.
FEMS Microbiol Ecol. 2006 May;56(2):310-20. doi: 10.1111/j.1574-6941.2006.00072.x.
Soil microbial communities play an important role in nutrient cycling and nutrient availability, especially in unimproved soils. In grazed pastures, sheep urine causes local changes in nutrient concentration which may be a source of heterogeneity in microbial community structure. In the present study, we investigated the effects of synthetic urine on soil microbial community structure, using physiological (community level physiological profiling, CLPP), biochemical (phospholipid fatty acid analysis, PLFA) and molecular (denaturing gradient gel electrophoresis, DGGE) fingerprinting methods. PLFA data suggested that synthetic urine treatment had no significant effect on total microbial (total PLFA), total bacterial or fungal biomass; however, significant changes in microbial community structure were observed with both PLFA and DGGE data. PLFA data suggested that synthetic urine induced a shift towards communities with higher concentrations of branched fatty acids. DGGE banding patterns derived from control and treated soils differed, due to a higher proportion of DNA sequences migrating only to the upper regions of the gel in synthetic urine-treated samples. The shifts in community structure measured by PLFA and DGGE were significantly correlated with one another, suggesting that both datasets reflected the same changes in microbial communities. Synthetic urine treatment preferentially stimulated the use of rhizosphere-C in sole-carbon-source utilisation profiles. The changes caused by synthetic urine addition accounted for only 10-15% of the total variability in community structure, suggesting that overall microbial community structure was reasonably stable and that changes were confined to a small proportion of the communities.
土壤微生物群落对养分循环和养分有效性起着重要作用，在未改良土壤中尤为如此。在放牧的牧场中，绵羊尿液会导致养分浓度发生局部变化，这可能是微生物群落结构异质性的一个来源。在本研究中，我们使用生理学方法（群落水平生理学分析，CLPP）、生化方法（磷脂脂肪酸分析，PLFA）和分子方法（变性梯度凝胶电泳，DGGE）指纹技术，研究了合成尿液对土壤微生物群落结构的影响。PLFA数据表明，合成尿液处理对总微生物量（总PLFA）、总细菌或真菌生物量没有显著影响；然而，通过PLFA和DGGE数据均观察到微生物群落结构发生了显著变化。PLFA数据表明，合成尿液促使微生物群落向具有较高浓度支链脂肪酸的群落转变。对照土壤和处理土壤的DGGE条带模式不同，这是因为在合成尿液处理的样品中，只有较高比例的DNA序列迁移到凝胶的上部区域。通过PLFA和DGGE测量的群落结构变化彼此显著相关，这表明两个数据集反映了微生物群落的相同变化。在单一碳源利用图谱中，合成尿液处理优先刺激了根际碳的利用。合成尿液添加引起的变化仅占群落结构总变异性的10-15%，这表明整体微生物群落结构相当稳定，变化仅限于一小部分群落。
