PS 47-220 - Soil total and ectomycorrhizal fungal community within loblolly pine and eucalypt tree roots and rhizospheres at the extreme ends of a groundwater depth gradient

Abstract: Fungi in soil ecosystems play important roles in decomposing organic materials and recycling nutrients thus affecting plant growth and the accretion and depletion of soil organic matter. Ectomycorrhizal fungi form mutualistic symbiotic relationship with their host plants, and greatly affect the host nutrient uptake and seedling establishment. A clear understanding on how biotic and abiotic factors influence the soil fungal community and its functional in plantation forest ecosystems is fundamental to terrestrial biogeochemistry and plant production. The purpose of this study was to investigate soil fungal, including ectomycorrhizal fungal communities, under a native pine tree species, loblolly pine (Pinus taeda), to southeastern United States, and an introduced eucalypt tree species Camden white gum (Eucalyptus benthamii), as a function of groundwater depth (deep and shallow) in different seasons (spring and fall). The relative abundance of soil fungal and ectomycorrhizal fungi was detected using quantitative PCR (q-PCR), and the soil general and ectomycorrhizal fungal communities were detected using Polymerase Chain Reaction (PCR) and Denaturing Gradient Gel Electrophoresis (DGGE). The soil fungal community was further compared using next generation Illumina sequencing. Relative abundance of the fungi from Basidimycota was higher in loblolly pine than in eucalypt, whereas, no difference of relative abundance was observed for the fungal taxa of Ascomycota between loblolly pine and eucalypt. Ectomycorrhizal colonization % was significantly lower in introduced eucalypt than in local loblolly pine, suggesting the limitation of introduced eucalypt becoming an invasive species in southeastern United States. Ectomycorrhizal colonization was significantly higher in spring than in fall. The seasonal difference of soil general and ectomycorrhizal fungal communities suggests soil fungi and ectomycorrhizal fungi exhibit seasonal dynamics that likely impact the nutrition and growth of pine and eucalypt tree species.