Differences in ectomycorrhizal fungal communities and enzyme activities between survived and planted on coastal embankment Pinus thunbergii

The 2011 off the Pacific coast of Tohoku earthquake and subsequent tsunami eradicated coastal forests as long as a total of 3,600 km shoreline. For the restoration of damaged forests, Pinus thunbergii seedlings were planted on embankments made from forest soils. P. thunbergii roots are colonized by symbiotic ectomycorrhizal (ECM) fungi, some of which decompose soil organic matter by secreting extracellular enzymes. Thus, ECM fungi can play a pivotal role for growth of host trees and to maintain coastal forests under harsh environmental conditions. The aim of this study was to clarify the effects of embankments on ECM fungal communities and their nutrient acquisition associated with P. thunbergii seedlings. ECM roots were collected from both planted seedlings and adjacent survived mature trees of P. thunbergii at a coastal site of northern part of Japan. ECM roots were observed under a stereomicroscope for mycorrhization being divided into morphotypes based on their colors. Among the morphotypes, the black ECM roots were identified as Cenococcum geophilum, an ascomycetous fungus with characteristics mycelial sheath and extrametrical hyphae. Representative morphotypes of ECM roots were quantified eight enzymatic activities related with nitrogen, phosphorus, and carbon sources using a microplate reader. DNA barcoding of the ITS region of the roots was performed to estimate fungal species. The rate of mycorrhization in mature trees ranged from 90.6% to 99.5%, and that in seedlings ranged from 40.5% to 93.8%. We will discuss the effects of forest soil embankments on ECM fungal communities and their nutrient acquisition functions.