School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA.
Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA.
Mycorrhiza. 2020 Jan;30(1):79-95. doi: 10.1007/s00572-020-00931-5. Epub 2020 Jan 22.
This study explores the relationships of AM fungal abundance and diversity with biotic (host plant, ungulate grazing) and abiotic (soil properties, precipitation) factors in the Serengeti National Park, Tanzania. Soil and root samples were collected from grazed and ungrazed plots at seven sites across steep soil fertility and precipitation gradients. AM fungal abundance in the soil was estimated from the density of spores and the concentration of a fatty acid biomarker. Diversity of AM fungi in roots and soils was measured using DNA sequencing and spore identification. AM fungal abundance in soil decreased with grazing and precipitation and increased with soil phosphorus. The community composition of AM fungal DNA in roots and soils differed. Root samples had more AM fungal indicator species associated with biotic factors (host plant species and grazing), and soil samples had more indicator species associated with particular sample sites. These findings suggest that regional edaphic conditions shape the site-level species pool from which plant species actively select root-colonizing fungal assemblages modified by grazing. Combining multiple measurements of AM fungal abundance and community composition provides the most informed assessment of the structure of mycorrhizal fungal communities in natural ecosystems.
本研究探讨了坦桑尼亚塞伦盖蒂国家公园中 AM 真菌丰度和多样性与生物因素（宿主植物、有蹄类放牧）和非生物因素（土壤性质、降水）之间的关系。从七个不同地点的放牧和未放牧斑块中采集了土壤和根系样本，这些地点横跨陡峭的土壤肥力和降水梯度。通过孢子密度和脂肪酸生物标志物浓度来估算土壤中 AM 真菌的丰度。通过 DNA 测序和孢子鉴定来测量根系和土壤中 AM 真菌的多样性。土壤中 AM 真菌的丰度随着放牧和降水的增加而减少，随着土壤磷的增加而增加。根和土壤中 AM 真菌 DNA 的群落组成不同。根样本中与生物因素（宿主植物种类和放牧）相关的 AM 真菌指示种较多，而土壤样本中与特定采样点相关的指示种较多。这些发现表明，区域土壤条件塑造了植物物种积极选择由放牧修饰的根定殖真菌组合的位点水平物种库。结合 AM 真菌丰度和群落组成的多种测量方法，可以更全面地评估自然生态系统中菌根真菌群落的结构。
