Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland.
Netherlands Food and Consumer Product Safety Authority, National Reference Centre, Wageningen, The Netherlands.
ISME J. 2022 May;16(5):1327-1336. doi: 10.1038/s41396-021-01159-7. Epub 2022 Jan 10.
Most trees form symbioses with ectomycorrhizal fungi (EMF) which influence access to growth-limiting soil resources. Mesocosm experiments repeatedly show that EMF species differentially affect plant development, yet whether these effects ripple up to influence the growth of entire forests remains unknown. Here we tested the effects of EMF composition and functional genes relative to variation in well-known drivers of tree growth by combining paired molecular EMF surveys with high-resolution forest inventory data across 15 European countries. We show that EMF composition was linked to a three-fold difference in tree growth rate even when controlling for the primary abiotic drivers of tree growth. Fast tree growth was associated with EMF communities harboring high inorganic but low organic nitrogen acquisition gene proportions and EMF which form contact versus medium-distance fringe exploration types. These findings suggest that EMF composition is a strong bio-indicator of underlying drivers of tree growth and/or that variation of forest EMF communities causes differences in tree growth. While it may be too early to assign causality or directionality, our study is one of the first to link fine-scale variation within a key component of the forest microbiome to ecosystem functioning at a continental scale.
大多数树木与外生菌根真菌（EMF）形成共生关系，后者影响植物对生长受限的土壤资源的获取。中尺度实验反复表明，EMF 物种会对植物的发育产生不同的影响，但这些影响是否会波及整个森林的生长仍然未知。在这里，我们通过结合配对的分子 EMF 调查和 15 个欧洲国家的高分辨率森林清查数据，检验了 EMF 组成和功能基因相对于树木生长的已知驱动因素的变化的影响。我们发现，即使控制了树木生长的主要非生物驱动因素，EMF 组成与树木生长速度的三倍差异有关。快速的树木生长与 EMF 群落中含有高无机但低有机氮获取基因比例以及形成接触或中距离边缘探索类型的 EMF 有关。这些发现表明，EMF 组成是树木生长的潜在驱动因素的有力生物指标，或者森林 EMF 群落的变异导致了树木生长的差异。虽然现在确定因果关系或方向性还为时过早，但我们的研究是首次将森林微生物组关键组成部分的细尺度变化与大陆尺度的生态系统功能联系起来。
