Arbuscular Mycorrhizal Tree Communities Have Greater Soil Fungal Diversity and Relative Abundances of Saprotrophs and Pathogens than Ectomycorrhizal Tree Communities
Arbuscular Mycorrhizal Tree Communities Have Greater Soil Fungal Diversity and Relative Abundances of Saprotrophs and Pathogens than Ectomycorrhizal Tree Communities
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DOI：
10.1128/aem.01782-21
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发表时间：
2022-01-01
影响因子：
4.4
通讯作者：
Blackwood, Christopher B.
中科院分区：
文献类型：
--
作者：
Eagar, Andrew C.;Mushinski, Ryan M.;Blackwood, Christopher B.
不同菌根组合的树木对凋落物分解、养分循环、土壤有机质(SOM)动态和植物-土壤相互作用的影响往往不同。例如，由于丛枝菌根(AM)和外生菌根(ECM)树叶和根系特征的不同，与丛枝菌根(ECM)相关的土壤具有较低的C、N循环速率和较低的N有效性。这些观察结果表明，许多非菌根真菌群应该通过控制营养物质的有效性而受到优势树种的菌根联合的影响。为了验证这一总体假设，我们利用下一代扩增序列技术探索了主要森林菌根类型和矿质氮有效性对土壤真菌群落的影响。研究了美国印第安纳州南部4个温带阔叶林的土壤，其中3个森林形成了菌根优势的自然梯度(100%AM树断面积到100%ECM断面积)，而第4个森林包含了一个因子实验，测试了两种优势菌根类型的长期氮素添加。我们发现，植物病原真菌和腐生真菌的多样性和相对丰富度随着AM树优势度的增加而增加。此外，与土壤深度、土壤有机质含量、硝化速率和矿质氮有效性等非生物变量相比，乔木群落菌根联合更能解释真菌群落组成的变化。我们的发现表明，树木菌根关联度可以很好地预测温带阔叶林土壤真菌群落的多样性、组成和功能潜力。这些观察结果有助于解释在不同菌根类型主导的森林中发现的不同生物地球化学和群落动态。重要的是，我们的工作探索了温带阔叶树不同的菌根组合(即丛枝菌根(AM)和外生菌根[ECM]组合)如何通过改变腐生性和植物病原性真菌的多样性和相对丰度来影响土壤真菌群落。由于随着气候变化，温带阔叶林预计将变得更加以AM为主，因此有必要沿菌根梯度研究土壤群落，以了解这些全球变化可能如何改变未来的土壤真菌群落及其功能潜力。我们的研究与最近的其他研究一起，确定了负责营养循环和植物-土壤相互作用的特定真菌功能群频率的可能全球趋势，因为它们与菌根协会有关。
Trees associating with different mycorrhizas often differ in their effects on litter decomposition, nutrient cycling, soil organic matter (SOM) dynamics, and plant-soil interactions. For example, due to differences between arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) tree leaf and root traits, ECM-associated soil has lower rates of C and N cycling and lower N availability than AM-associated soil. These observations suggest that many groups of nonmycorrhizal fungi should be affected by the mycorrhizal associations of dominant trees through controls on nutrient availability. To test this overarching hypothesis, we explored the influence of predominant forest mycorrhizal type and mineral N availability on soil fungal communities using next-generation amplicon sequencing. Soils from four temperate hardwood forests in southern Indiana, United States, were studied; three forests formed a natural gradient of mycorrhizal dominance (100% AM tree basal area to 100% ECM basal area), while the fourth forest contained a factorial experiment testing long-term N addition in both dominant mycorrhizal types. We found that overall fungal diversity, as well as the diversity and relative abundance of plant pathogenic and saprotrophic fungi, increased with greater AM tree dominance. Additionally, tree community mycorrhizal associations explained more variation in fungal community composition than abiotic variables, including soil depth, SOM content, nitrification rate, and mineral N availability. Our findings suggest that tree mycorrhizal associations may be good predictors of the diversity, composition, and functional potential of soil fungal communities in temperate hardwood forests. These observations help explain differing biogeochemistry and community dynamics found in forest stands dominated by differing mycorrhizal types.IMPORTANCE Our work explores how differing mycorrhizal associations of temperate hardwood trees (i.e., arbuscular (AM) versus ectomycorrhizal [ECM] associations) affect soil fungal communities by altering the diversity and relative abundance of saprotrophic and plant-pathogenic fungi along natural gradients of mycorrhizal dominance. Because temperate hardwood forests are predicted to become more AM dominant with climate change, studies examining soil communities along mycorrhizal gradients are necessary to understand how these global changes may alter future soil fungal communities and their functional potential. Ours, along with other recent studies, identify possible global trends in the frequency of specific fungal functional groups responsible for nutrient cycling and plant-soil interactions as they relate to mycorrhizal associations.