Temperate Forests Dominated by Arbuscular or Ectomycorrhizal Fungi Are Characterized by Strong Shifts from Saprotrophic to Mycorrhizal Fungi with Increasing Soil Depth
Temperate Forests Dominated by Arbuscular or Ectomycorrhizal Fungi Are Characterized by Strong Shifts from Saprotrophic to Mycorrhizal Fungi with Increasing Soil Depth
复制标题
DOI：
10.1007/s00248-020-01540-7
复制
发表时间：
2020-06-17
影响因子：
3.6
通讯作者：
Laliberte, Etienne
中科院分区：
文献类型：
--
作者：
Carteron, Alexis;Beigas, Marie;Laliberte, Etienne
在温带和北方森林中，自由生长的腐养菌和外生菌根（EcM）真菌对土壤资源的竞争限制了腐养真菌在EcM树木占主导地位的森林中最浅层有机土壤层的优势地位。相比之下，与丛枝菌根（AM）真菌的低生态位重叠可以使真菌腐生菌在AM优势森林中保持这种优势，进入更深的土壤层。在这里，我们使用由AM或EcM树或两者混合主导的邻近森林斑块的自然梯度来确定高通量扩增子测序特征的真菌群落如何在有机和矿物土壤层中变化。我们发现，随着土壤深度的增加，所有森林菌根真菌类型的优势都从腐坏性向菌根真菌优势转变，特别是在有机层。土壤化学的垂直变化，包括pH、有机质、可交换阳离子和可提取磷，与真菌群落组成的变化一致。虽然真菌群落和土壤化学在邻近的森林菌根类型之间存在差异，但在给定的土壤剖面内变化更大，这表明在表征土壤真菌群落时考虑视界的重要性。我们的研究结果还表明，在温带森林中，在有机和矿物层中，从腐养真菌到菌根真菌的垂直转变在外生菌根森林和丛枝菌根森林中都有类似的发生。
In temperate and boreal forests, competition for soil resources between free-living saprotrophs and ectomycorrhizal (EcM) fungi has been suggested to restrict saprotrophic fungal dominance to the most superficial organic soil horizons in forests dominated by EcM trees. By contrast, lower niche overlap with arbuscular mycorrhizal (AM) fungi could allow fungal saprotrophs to maintain this dominance into deeper soil horizons in AM-dominated forests. Here we used a natural gradient of adjacent forest patches that were dominated by either AM or EcM trees, or a mixture of both to determine how fungal communities characterized with high-throughput amplicon sequencing change across organic and mineral soil horizons. We found a general shift from saprotrophic to mycorrhizal fungal dominance with increasing soil depth in all forest mycorrhizal types, especially in organic horizons. Vertical changes in soil chemistry, including pH, organic matter, exchangeable cations, and extractable phosphorus, coincided with shifts in fungal community composition. Although fungal communities and soil chemistry differed among adjacent forest mycorrhizal types, variations were stronger within a given soil profile, pointing to the importance of considering horizons when characterizing soil fungal communities. Our results also suggest that in temperate forests, vertical shifts from saprotrophic to mycorrhizal fungi within organic and mineral horizons occur similarly in both ectomycorrhizal and arbuscular mycorrhizal forests.