Mycorrhizal fungal communities respond to experimental elevation of soil pH and P availability in temperate hardwood forests

• Published in: FEMS microbiology ecology 2016-03, Vol.92 (3), p.1
• Main Authors: Carrino-Kyker, Sarah R., Kluber, Laurel A., Petersen, Sheryl M., Coyle, Kaitlin P., Hewins, Charlotte R., DeForest, Jared L., Smemo, Kurt A., Burke, David J.
• Format: Article
• Language: English
• Subjects: 454-sequencing; acid deposition; arbuscular mycorrhizal fungi; BASIC BIOLOGICAL SCIENCES; Biomass; Chemical properties; Distribution; Ecosystem; ectomycorrhizal fungi; Environmental aspects; Forests; Forests and forestry; Fungi; Fungi - genetics; Fungi - growth & development; Fungi - isolation & purification; Fungi - metabolism; Hydrogen-Ion Concentration; Microbial colonies; Mycorrhizae - genetics; Mycorrhizae - growth & development; Mycorrhizae - isolation & purification; Mycorrhizae - metabolism; Mycorrhizas; phosphatase; phosphorus; Phosphorus - analysis; Phosphorus - metabolism; Plant Roots - microbiology; Soil - chemistry; Soil Microbiology; Soils; Trees - growth & development; Trees - microbiology; United States
• ISSN: 1574-6941; 0168-6496; 1574-6941
• DOI: 10.1093/femsec/fiw024

Many forests are affected by chronic acid deposition, which can lower soil pH and limit the availability of nutrients such as phosphorus (P), but the response of mycorrhizal fungi to changes in soil pH and P availability and how this affects tree acquisition of nutrients is not well understood. Here, we describe an ecosystem-level manipulation in 72 plots, which increased pH and/or P availability across six forests in Ohio, USA. Two years after treatment initiation, mycorrhizal fungi on roots were examined with molecular techniques, including 454-pyrosequencing. Elevating pH significantly increased arbuscular mycorrhizal (AM) fungal colonization and total fungal biomass, and affected community structure of AM and ectomycorrhizal (EcM) fungi, suggesting that raising soil pH altered both mycorrhizal fungal communities and fungal growth. AM fungal taxa were generally negatively correlated with recalcitrant P pools and soil enzyme activity, whereas EcM fungal taxa displayed variable responses, suggesting that these groups respond differently to P availability. Additionally, the production of extracellular phosphatase enzymes in soil decreased under elevated pH, suggesting a shift in functional activity of soil microbes with pH alteration. Thus, our findings suggest that elevating pH increased soil P availability, which may partly underlie the mycorrhizal fungal responses we observed. Though decades of acidic deposition have contributed to reduce soil pH in forests worldwide, experimentally raising pH changes mycorrhizal fungi colonizing tree roots and alters phosphorus availability. Graphical Abstract Figure. Though decades of acidic deposition have contributed to reduce soil pH in forests worldwide, experimentally raising pH changes mycorrhizal fungi colonizing tree roots and alters phosphorus availability.