van Geel Maarten, Ceustermans An, van Hemelrijck Wendy, Lievens Bart, Honnay Olivier
Plant Conservation and Population Biology, Department of Biology, KU Leuven, Kasteelpark Arenberg 31, Heverlee, B-3001, Belgium.
Mol Ecol. 2015 Feb;24(4):941-52. doi: 10.1111/mec.13079. Epub 2015 Feb 2.
Understanding which factors drive the diversity and community composition of arbuscular mycorrhizal fungi (AMF) is important due to the role of these soil micro-organisms in ecosystem functioning and current environmental threats to AMF biodiversity. Additionally, in agro-ecosystems, this knowledge may help to evaluate their use in making agriculture more sustainable. Here, we used 454-pyrosequencing of small subunit rRNA gene amplicons to quantify AMF diversity and community composition in the roots of cultivated apple trees across 24 orchards in central Belgium. We aimed at identifying the factors (soil chemical variables, organic vs. conventional farming, and geographical location) that affect AMF diversity and community composition. In total, 110 AMF OTUs were detected, of which the majority belonged to the Glomeraceae (73%) and the Claroideoglomeraceae (19%). We show that soil characteristics and farming system, rather than the geographical location of the orchards, shape AMF communities on apple trees. Particularly, plant-available P content of the soil was associated with lower AMF diversity. In orchards with a lower plant-available P content of the soil (P < 100 mg/kg soil), we also found a significantly higher AMF diversity in organically managed orchards as compared to conventionally managed orchards. Finally, the degree of nestedness of the AMF communities was related to plant-available P and N content of the soil, pointing at a progressive loss of AMF taxa with increasing fertilization. Overall, we conclude that a combination of organic orchard management and moderate fertilization may preserve diverse AMF communities on apple trees and that AMF in the roots of apple trees appear not to be dispersal limited at the scale of central Belgium.
了解哪些因素驱动丛枝菌根真菌（AMF）的多样性和群落组成至关重要，因为这些土壤微生物在生态系统功能中发挥着作用，且目前面临着对AMF生物多样性的环境威胁。此外，在农业生态系统中，这方面的知识可能有助于评估它们在使农业更具可持续性方面的用途。在此，我们利用小亚基rRNA基因扩增子的454焦磷酸测序技术，对比利时中部24个果园中栽培苹果树根系的AMF多样性和群落组成进行了量化。我们旨在确定影响AMF多样性和群落组成的因素（土壤化学变量、有机种植与传统种植以及地理位置）。总共检测到110个AMF操作分类单元（OTU），其中大多数属于球囊霉科（73%）和类球囊霉科（19%）。我们发现，塑造苹果树上AMF群落的是土壤特性和种植系统，而非果园的地理位置。特别是，土壤中植物有效磷含量与较低的AMF多样性相关。在土壤植物有效磷含量较低（P < 100 mg/kg土壤）的果园中，我们还发现，与传统管理的果园相比，有机管理的果园中AMF多样性显著更高。最后，AMF群落的嵌套程度与土壤中植物有效磷和氮的含量有关，这表明随着施肥量增加，AMF分类群逐渐减少。总体而言，我们得出结论，有机果园管理与适度施肥相结合可能会保护苹果树上多样 的AMF群落，并且在比利时中部尺度上，苹果树根中的AMF似乎不存在扩散限制。
