Ectomycorrhizal Fungi Associated with Pinus densiflora Seedlings under Flooding Stress

Flooding is an environmental stress for plants that not only limits aeration and nutrient acquisition, but also disturbs underground plant-associated fungal communities. Despite frequent flooding, red pine (Pinus densiflora) seedlings thrive in streamside environments. However, whether the compatible ectomycorrhizal fungi (EMF) of red pine are affected by natural flooding is unclear. As EMF are vital symbionts for the development of many trees and allow them to overcome various environmental stresses, in this study, the EMF species associated with red pine seedlings in a streamside environment in Korea were investigated after flooding. The EMF species in 47 seedlings collected from the streamside site were identified by observing their different morphotypes using internal transcribed spacer sequence analysis, and a total of 10 EMF species were identified. The EMF species diversity was lower than that in samples collected from a nearby forest analyzed as a control. The dominant EMF species of streamside seedlings included Amphinema spp., Rhizopogon luteolus, Suillus luteus, and Thelephora terrestris. This study could serve as a basis for investigating the mechanisms by which advantageous EMF aid plant development under flooding stress.

Soil Fungal Community in Norway Spruce Forests under Bark Beetle Attack

Bark beetle infestation is a widespread phenomenon in temperate forests, which are facing significant weather fluctuations accompanying climate change. Fungi play key roles in forest ecosystems as symbionts of ectomycorrhizal trees, decomposers, or parasites, but the effect of severe disturbances on their communities is largely unknown. The responses of soil fungal communities following bark beetle attack were determined using Illumina sequencing of soil samples from 10 microsites in a mature forest not attacked by bark beetle, a forest attacked by bark beetle, a forest destroyed by bark beetle, and a stand where all trees were removed after a windstorm. The proportion of ITS2 sequences assigned to mycorrhizal fungal species decreased with increased intensity of bark beetle attack (from 70 to 15%), whereas the proportion of saprotrophs increased (from 29 to 77%). Differences in the ectomycorrhizal (ECM) fungal community was further characterized by a decrease in the sequence proportion of Elaphomyces sp. and Russula sp. and an increase in Piloderma sp., Wilcoxina sp., and Thelephora terrestris. Interestingly, the species composition of the ECM fungal community in the forest one year after removing the windstorm-damaged trees was similar to that of the mature forest, despite the sequence proportion attributed to ECM fungi decreased.

Persistence of ectomycorrhizas by Thelephora terrestris on outplanted Scots pine seedlings

<em>Thelephora terrestris</em> (Erhr.) Fr. is a very common ectomycorrhizal symbiont (ECM) in conifer trees, however the role of this ubiquitous fungus in nurseries and Scots pine plantations is still unknown. It is described as tolerant of high nitrogen availability and therefore was taken into consideration as an important ECM partner of seedlings, particularly after replanting on post agricultural land. In laboratory the seedlings of Scots pine (<em>Pinus sylvestris</em> L.) were inoculated with <em>T. terrestris</em> (Tt/IBL/2) or not inoculated (control) and grown in containers in two different regimes of nitrogen fertilization (4g N x kg^-1 and 6 g N x kg^-1). Next year these seedlings were outplanted in post agricultural land and 6 months later, the number and identity of some mycorrhizas were studied. It was found, that mycorrhizal abundance was higher in the inoculated treatments than in non-inoculated ones. PCR RFLP analysis confirmed share of two different isolates of <em>Thelephora</em> engaged in mycorrhizal symbiosis. Part of mycorrhizas had the same pattern of RFLP as the isolate used to inoculation. Similar results were obtained in second year of experimental study in the field what confirmed the persistence of artificially introduced <em>T. terrestris</em> in post agricultural soil as an important component of the ECM community.

Influence of N-fertilized substrata on biometric parameters and nitrogen content of seedlings with Thelephora terrestris

Wpływ azotu w podłożu na cechy biometryczne oraz zawartość tego pierwiastka w siewkach sosny zwyczajnej z mikoryząThelephora terrestris