Institut de recherche en biologie végétale, Université de Montréal and Jardin botanique de Montréal, 4101 Sherbrooke Street East, Montreal, Quebec, Canada H1X 2B2.
Mycorrhiza. 2013 Feb;23(2):143-54. doi: 10.1007/s00572-012-0459-6. Epub 2012 Sep 9.
Arbuscular mycorrhizal (AM) fungi are key components of most agricultural ecosystems. Therefore, understanding the impact of agricultural practices on their community structure is essential to improve nutrient mobilization and reduce plant stress in the field. The effects of five different organic or mineral sources of phosphorus (P) for a maize-soybean rotation system on AM fungal diversity in roots and soil were assessed over a 3-year period. Total DNA was extracted from root and soil samples collected at three different plant growth stages. An 18S rRNA gene fragment was amplified and taxa were detected and identified using denaturing gradient gel electrophoresis followed by sequencing. AM fungal biomass was estimated by fatty acid methyl ester analysis. Soil P fertility parameters were also monitored and analyzed for possible changes related with fertilization or growth stages. Seven AM fungal ribotypes were detected. Fertilization significantly modified soil P flux, but had barely any effect on AM fungi community structure or biomass. There was no difference in the AM fungal community between plant growth stages. Specific ribotypes could not be significantly associated to P treatment. Ribotypes were associated with root or soil samples with variable detection frequencies between seasons. AM fungal biomass remained stable throughout the growing seasons. This study demonstrated that roots and soil host distinct AM fungal communities and that these are very temporally stable. The influence of contrasting forms of P fertilizers was not significant over 3 years of crop rotation.
丛枝菌根（AM）真菌是大多数农业生态系统的关键组成部分。因此，了解农业实践对其群落结构的影响对于改善养分动员和减少田间植物胁迫至关重要。在 3 年的时间里，评估了 5 种不同的有机或矿物磷（P）源对玉米-大豆轮作系统中 AM 真菌多样性在根系和土壤中的影响。从不同的植物生长阶段采集的根和土壤样本中提取总 DNA。通过变性梯度凝胶电泳（DGGE）后测序扩增 18S rRNA 基因片段，并检测和鉴定分类群。通过脂肪酸甲酯分析估算 AM 真菌生物量。还监测和分析了土壤 P 肥力参数，以寻找与施肥或生长阶段相关的可能变化。检测到 7 种 AM 真菌核糖体型。施肥显著改变了土壤 P 通量，但对 AM 真菌群落结构或生物量几乎没有影响。在植物生长阶段，AM 真菌群落没有差异。特定核糖体型不能与 P 处理显著相关。核糖体型与根或土壤样本相关，在不同季节的检测频率不同。整个生长季节，AM 真菌生物量保持稳定。本研究表明，根系和土壤中存在不同的 AM 真菌群落，并且这些群落非常具有时间稳定性。在 3 年的作物轮作中，不同形式的 P 肥料的影响并不显著。
