Hokkaido University · Agricultural and Biological Sciences
Professor Chikae Tatsumi's research lab focuses on the ecological and microbial dynamics underlying forest soil health, particularly the roles of mycorrhizal fungi in regulating nutrient cycling, carbon storage, and plant-microbe interactions. The lab investigates how urbanization and land-use change disrupt symbiotic relationships between trees and their fungal partners—especially ectomycorrhizal (ECM) fungi—impacting soil microbial community structure and function. A central theme is understanding the competition for nitrogen among soil microbes and mycorrhizal fungi, and how this affects ecosystem stability and forest regeneration. The lab also explores the biochemical mechanisms of enzyme stability, particularly in thermolysin, to understand protein-salt interactions at the molecular level.
Figures are computed from collected data and may differ slightly.
Mycorrhizal fungi have considerable effects on soil carbon (C) storage, as they control the decomposition of soil organic matter (SOM), by modifying the amount of soil nitrogen (N) available for free-living microbes. Through their access to organic N, ectomycorrhizal (ECM) fungi compete with free-living soil microbes; this competition is thought to slow down SOM decomposition. However, arbuscular mycorrhizal (AM) fungi cannot decompose SOM, and therefore must wait for N to first be processed by
Temperate forests are threatened by urbanization and fragmentation, with over 20% (118,300 km<sup>2</sup>) of U.S. forest land projected to be subsumed by urban land development. We leveraged a unique, well-characterized urban-to-rural and forest edge-to-interior gradient to identify the combined impact of these two land use changes-urbanization and forest edge creation-on the soil microbial community in native remnant forests. We found evidence of mutualism breakdown between trees and their fun
Thermolysin is remarkably activated and stabilized by neutral salts with varying degrees depending on salt species, and particular surface residues are thought to be especially important in its activity and stability [Inouye, K. (1992) J. Biochem. 112, 335-340; Inouye, K. et al. (1998) Biochim. Biophys. Acta 1388, 209-214]. In this study, we examined the mutational effects of the surface residues of thermolysin. Gln128 and Gln225 were selected as the residues to be mutated because they are locat
Nitrogen (N) is an essential plant nutrient, and plants can take up N from several sources, including via mycorrhizal fungal associations. The N uptake patterns of understory plants may vary beneath different types of overstory trees, especially through the difference in their type of mycorrhizal association (arbuscular mycorrhizal, AM; or ectomycorrhizal, ECM), because soil mycorrhizal community and N availability differ beneath AM (non-ECM) and ECM overstory trees (e.g., relatively low nitrate
Abstract Temperate forests are particularly threatened by urbanization and fragmentation, with over 20% (120lJ000 km 2 ) of recently urbanized land in the U.S. subsuming natural forests. We leveraged a unique, well-characterized urban-to-rural and forest edge-to-interior gradient to identify the combined impact of these two land use changes - urbanization and forest fragmentation - on soil microbial community in native, remnant forests. We found evidence of mutualism breakdown between trees and
Native tree species are frequently unable to effectively grow in non-native tree cultivation scenarios. In the Loess Plateau, China, it is difficult to find native oak (Quercus liaotungensis) seedlings in non-native black locust forests. Black locust is an arbuscular mycorrhizal (AM) tree, but oak is an ectomycorrhizal (ECM) tree. Plants highly depend on their symbiotic mycorrhizal fungi to take up water, nitrogen (N) and other nutrients. We hypothesized that black locust forests would not provi
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