Mycorrhiza better predict soil fungal community composition and function than aboveground traits in temperate forest ecosystems

We sampled soil in the organic and mineral horizons beneath two AM-associated (Fraxinus americana, Thuja occidentalis) and two ECM-associated tree species (Betula alleghaniensis, and Tsuga canadensis), with an evergreen and deciduous species in each mycorrhizal group. To characterize fungal communities and organic matter decomposition beneath each tree species, we sequenced the ITS1 region of fungal DNA and measured the potential activity of carbon and nitrogen-targeting extracellular enzymes. Each tree species harbored distinct fungal communities, supporting the need to consider both mycorrhizal type and leaf habit. However, between tree characteristics, mycorrhizal type better predicted fungal communities. Across fungal guilds, saprotrophic fungi were the most important group in shaping fungal community differences in soils beneath all tree species. The effect of leaf habit on carbon and nitrogen-targeting hydrolytic enzymes depended on tree mycorrhizal association in the organic horizon, while oxidative enzyme activities were higher beneath EcM-associated trees across both soil horizons and leaf habits. These data include extracellular hydrolytic and oxidative enzyme activities, ITS sequencing fungal community data, soil carbon to nitrogen, and soil pH. Site level data include climate (mean annual temperature, precipitation), elevation, and soil series and order information.

我们采集了两种丛枝菌根（Arbuscular Mycorrhizal, AM）共生树种（美国白蜡*Fraxinus americana*、北美香柏*Thuja occidentalis*）与两种外生菌根（Ectomycorrhizal, ECM）共生树种（黄桦*Betula alleghaniensis*、加拿大铁杉*Tsuga canadensis*）根际的有机层与矿质层土壤样本，且两类菌根组中均各包含1种常绿树种与1种落叶树种。为表征各树种根际的真菌群落结构与有机质分解潜能，我们对真菌DNA的ITS1区进行测序，并测定了靶向碳、氮的胞外酶潜在活性。各树种均拥有独特的真菌群落，这表明相关研究需同时考虑菌根类型与叶片习性。但在诸多树木性状中，菌根类型对真菌群落的预测效果更佳。在所有真菌功能群中，腐生真菌是驱动所有树种根际土壤真菌群落差异的核心类群。有机层中，叶片习性对靶向碳、氮的水解酶活性的影响依赖于树木的菌根共生类型；而无论土壤层次与叶片习性如何，外生菌根（ECM）共生树种根际的氧化酶活性均更高。本数据集包含胞外水解酶与氧化酶活性数据、真菌ITS测序群落数据、土壤碳氮比数据以及土壤pH值。样地水平数据则包含气候因子（年均温、年降水量）、海拔，以及土壤系列与土纲分类信息。