Browsing by Subject "MYCORRHIZAL FUNGI"

Sort by: Order: Results:

Now showing items 1-12 of 12
  • Vaario, Lu-Min; Asamizu, Shumpei; Sarjala, Tytti; Matsushita, Norihisa; Onaka, Hiroyasu; Xia, Yan; Kurokochi, Hiroyuki; Morinaga, Shin-Ichi; Huang, Jian; Zhang, Shijie; Lian, Chunlan (2020)
    Tricholoma matsutake is known to be the dominant fungal species in matsutake fruitbody neighboring (shiro) soil. To understand the mechanisms behind matsutake dominance, we studied the bacterial communities in matsutake dominant shiro soil and non-shiro soil, isolated the strains of Streptomyces from matsutake mycorrhizal root tips both from shiro soil and from the Pinus densiflora seedlings cultivated in shiro soil. Further, we investigated three Streptomyces spp. for their ability to inhibit fungal growth and Pinus densiflora seedling root elongation as well as two strains for their antifungal and antioxidative properties. Our results showed that Actinobacteria was the most abundant phylum in shiro soil. However, the differences in the Actinobacterial community composition (phylum or order level) between shiro and non-shiro soils were not significant, as indicated by PERMANOVA analyses. A genus belonging to Actinobacteria, Streptomyces, was present on the matsutake mycorrhizas, although in minority. The two antifungal assays revealed that the broths of three Streptomyces spp. had either inhibitory, neutral or promoting effects on the growth of different forest soil fungi as well as on the root elongation of the seedlings. The extracts of two strains, including one isolated from the P. densiflora seedlings, inhibited the growth of either pathogenic or ectomycorrhizal fungi. The effect depended on the medium used to cultivate the strains, but not the solvent used for the extraction. Two Streptomyces spp. showed antioxidant activity in one out of three assays used, in a ferric reducing antioxidant power assay. The observed properties seem to have several functions in matsutake shiro soil and they may contribute to the protection of the shiro area for T. matsutake dominance.
  • Hilasvuori, Emmi; Hari, Pertti; Aakala, Tuomas; Pulliainen, Erkki; Grace, John (2014)
  • Hui, Nan; Liu, Xinxin; Kotze, D. Johan; Jumpponen, Ari; Francini, Gaia; Setala, Heikki (2017)
    Ectomycorrhizal (ECM) fungi are important mutualists for the growth and health of most boreal trees. Forest age and its host species composition can impact the composition of ECM fungal communities. Although plentiful empirical data exist for forested environments, the effects of established vegetation and its successional trajectories on ECM fungi in urban greenspaces remain poorly understood. We analyzed ECM fungi in 5 control forests and 41 urban parks of two plant functional groups (conifer and broadleaf trees) and in three age categories (10, similar to 50, and > 100 years old) in southern Finland. Our results show that although ECM fungal richness was marginally greater in forests than in urban parks, urban parks still hosted rich and diverse ECM fungal communities. ECM fungal community composition differed between the two habitats but was driven by taxon rank order reordering, as key ECM fungal taxa remained largely the same. In parks, the ECM communities differed between conifer and broadleaf trees. The successional trajectories of ECM fungi, as inferred in relation to the time since park construction, differed among the conifers and broadleaf trees: the ECM fungal communities changed over time under the conifers, whereas communities under broadleaf trees provided no evidence for such age-related effects. Our data show that plant-ECM fungus interactions in urban parks, in spite of being constructed environments, are surprisingly similar in richness to those in natural forests. This suggests that the presence of host trees, rather than soil characteristics or even disturbance regime of the system, determine ECM fungal community structure and diversity. IMPORTANCE In urban environments, soil and trees improve environmental quality and provide essential ecosystem services. ECM fungi enhance plant growth and performance, increasing plant nutrient acquisition and protecting plants against toxic compounds. Recent evidence indicates that soil-inhabiting fungal communities, including ECM and saprotrophic fungi, in urban parks are affected by plant functional type and park age. However, ECM fungal diversity and its responses to urban stress, plant functional type, or park age remain unknown. The significance of our study is in identifying, in greater detail, the responses of ECM fungi in the rhizospheres of conifer and broadleaf trees in urban parks. This will greatly enhance our knowledge of ECM fungal communities under urban stresses, and the findings can be utilized by urban planners to improve urban ecosystem services.
  • Manninen, Sirkku; Zverev, Vitali; Kozlov, Mikhail (2022)
    Long-term exposure to primary air pollutants, such as sulphur dioxide (SO2) and nitrogen oxides (NOx), alters the structure and functions of forest ecosystems. Many biochemical and biogeochemical processes discriminate against the heavier isotopes in a mixture; thus, the values of delta C-13 and delta N-15 (i.e. the ratio of stable isotopes C-13 to C-12 and that of (15) N to (14) N, respectively) may give insights into changes in ecosystem processes and identify the immediate drivers of these changes. We studied sources of variation in the delta C-13 and delta N-15 values in the foliage of eight boreal forest C3 plants at 10 sites located at the distance of 1-40 km from the Monchegorsk nickel-copper smelter in Russia. From 1939-2019, this smelter emitted over 14,000,000 metric tons (t) of SO2, 250,000 t of metals, primarily nickel and copper, and 140,000 t of NOx. The delta C-13 value in evergreen plants and the delta N-15 value in all plants increased near the smelter independently of the plant mycorrhizal type. We attribute the pollution-related increase in the foliar delta C-13 values of evergreen species mainly to direct effects of SO2 on stomatal conductance, in combination with pollution-related water stress, which jointly override the potential opposite effect of increasing ambient CO2 concentration on delta C-13 values. Stomatal uptake of NOx and root uptake of N-15-enriched organic N compounds and NH4+ may explain the increased foliar delta N-15 values and elevated foliar N concentrations, especially in the evergreen trees (Pinus sylvestris), close to Monchegorsk, where the soil inorganic N supply is reduced due to the impact of long-term SO2 and heavy metal emissions on plant biomass. We conclude that, despite the uncertainties in interpreting delta C-13 and delta N-15 responses to pollution, the Monchegorsk smelter has imposed and still imposes a great impact on C and N cycling in the surrounding N-limited subarctic forest ecosystems.
  • Aaltonen, Heidi; Koster, Kajar; Koster, Egle; Berninger, Frank; Zhou, Xuan; Karhu, Kristiina; Biasi, Christina; Bruckman, Viktor; Palviainen, Marjo; Pumpanen, Jukka (2019)
    Wildfires burn approximately 1% of boreal forest yearly, being one of the most significant factors affecting soil organic matter (SOM) pools. Boreal forests are largely situated in the permafrost zone, which contains half of global soil carbon (C). Wildfires advance thawing of permafrost by burning the insulating organic layer and decreasing surface albedo, thus increasing soil temperatures. Fires also affect SOM quality through chemical and physical changes, such as the formation of resistant C compounds. The long-term post-fire effects on SOM quality, degradability and isotopic composition are not well known in permafrost forests. We studied the effect of forest fires on the proportional sizes of SOM pools with chemical fractionation (extracting with water, ethanol and acid) of soil samples (5, 30 and 50cm depths) collected from a fire chronosequence in the upland mineral soils of the Canadian permafrost zone. We also determined the C-13 and N-15 isotopic composition of soil after fire. In the topsoil horizon (5cm) recent fire areas contained a smaller fraction of labile SOM and were slightly more enriched with N-15 and C-13 than older fire areas. The SOM fraction ratios reverted towards pre-fire status with succession. Changes in SOM were less apparent deeper in the soil. Best predictors for the size of recalcitrant SOM fraction were active layer depth, vegetation biomass and soil C/N ratio, whereas microbial biomass was best predicted by the size of the recalcitrant SOM fraction. Results indicated that SOM in upland mineral soils at the permafrost surface could be mainly recalcitrant and its decomposition not particularly sensitive to changes resulting from fire.
  • Kiheri, Heikki; Velmala, Sannakajsa; Pennanen, Taina; Timonen, Sari; Sietiö, Outi-Maaria; Fritze, Hannu; Heinonsalo, Jussi; van Dijk, Netty; Dise, Nancy; Larmola, Tuula (2020)
    Northern peatlands are often dominated by ericaceous shrub species which rely on ericoid mycorrhizal fungi (ERM) for access to organic sources of nutrients, such as nitrogen (N) and phosphorus (P), and host abundant dark septate endophytes (DSE). Relationships between hosts and fungal symbionts may change during deposition of anthropogenic N and P. We studied the long-term effects of N and P addition on two ericaceous shrubs, Calluna vulgaris and Erica tetralix, at Whim Bog, Scotland by analyzing fungal colonization of roots, enzymatic activity, and fungal species composition. Unexpectedly, the frequency of typical ERM intracellular colonization did not change while the occurrence of ERM hyphae tended to increase and DSE hyphae to decrease. Our findings indicate that altered nutrient limitations shift root associated fungal colonization patterns as well as affecting ericaceous root enzyme activity and thereby decomposition potential. Reduction of recalcitrant fungal biomass in melanized DSE may have implications for peatland C sequestration under nutrient addition.
  • Mikola, Juha; Koikkalainen, Katariina; Rasehorn, Mira; Silfver, Tarja; Paaso, Ulla; Rousi, Matti (2021)
    Fast-growing and slow-growing plant species are suggested to show integrated economics spectrums and the tradeoffs of fast growth are predicted to emerge as susceptibility to herbivory and resource competition. We tested if these predictions also hold for fast-growing and slow-growing genotypes within a silver birch, Betula pendula population. We exposed cloned saplings of 17 genotypes with slow, medium or fast height growth to reduced insect herbivory, using an insecticide, and to increasing resource competition, using naturally varying field plot grass cover. We measured shoot and root growth, ectomycorrhizal (EM) fungal production using ergosterol analysis and soil N transfer to leaves using N-15-labelled pulse of NH4+. We found that fast-growing genotypes grew on average 78% faster, produced 56% and 16% more leaf mass and ergosterol, and showed 78% higher leaf N uptake than slow-growing genotypes. The insecticide decreased leaf damage by 83% and increased shoot growth, leaf growth and leaf N uptake by 38%, 52% and 76%, without differences between the responses of fast-growing and slow-growing genotypes, whereas root mass decreased with increasing grass cover. Shoot and leaf growth of fast-growing genotypes decreased and EM fungal production of slow-growing genotypes increased with increasing grass cover. Our results suggest that fast growth is genotypically associated with higher allocation to EM fungi, better soil N capture and greater leaf production, and that the tradeoff of fast growth is sensitivity to competition, but not to insect herbivory. EM fungi may have a dual role: to support growth of fast-growing genotypes under low grass competition and to maintain growth of slow-growing genotypes under intensifying competition.
  • Guo, Qingxue; Wu, Xiaoyi; Korpelainen, Helena; Li, Chunyang (2020)
    Plant-plant competition is a dynamic and complicated process that is strongly influenced by abiotic conditions. Drought is a critical threat to forests, particularly to young plantation forests. Temporal changes in competition combined with the effects of drought may dramatically influence the physiological traits of plants. Cunninghamia lanceolata plants exposed to intra-specific competition and no-competition conditions were investigated under two soil water levels (well-watered and drought). Changes in plant-plant competition relationships and nitrogen uptake rates were measured at different harvest times. The effects of drought and plant competition on physiological traits, for example, leaf nitrogen allocation, δ13C, and levels of abscisic acid (ABA), indole acetic acid (IAA) and jasmonic acid (JA), were also explored. Our results indicated that C. lanceolata shifted from intense neighbor competition to facilitation under well-watered conditions, whereas under drought neighbor competition became much stronger at the second harvest compared to the first harvest. Strong competition significantly decreased N uptake under drought. Leaf NH4+, NO3- and N allocation to water-soluble proteins increased under drought at the first harvest, but significantly declined under prolonged drought. Leaf, stem and root starch concentrations were enhanced by drought. However, during prolonged drought, the root starch concentrations, leaf δ13C, leaf ABA and starch content of C. lanceolata were much lower under strong neighbor competition than in no-competition conditions, which demonstrated that the combined effects of drought and strong competition were more harmful to plant growth and survival compared to single effects. Our study demonstrated that drought combined with competition strongly affected the N uptake, N allocation and physiological traits of plants. Intense competition imposed by neighbors is a great threat to the growth and survival of young C. lanceolata plantations under prolonged drought.
  • Prescott, Cindy E.; Grayston, Sue J.; Helmisaari, Heljä-Sisko; Kastovska, Eva; Körner, Christian; Lambers, Hans; Meier, Ina C.; Millard, Peter; Ostonen, Ivika (2020)
    Plant growth is usually constrained by the availability of nutrients, water, or temperature, rather than photosynthetic carbon (C) fixation. Under these conditions leaf growth is curtailed more than C fixation, and the surplus photosynthates are exported from the leaf. In plants limited by nitrogen (N) or phosphorus (P), photosynthates are converted into sugars and secondary metabolites. Some surplus C is translocated to roots and released as root exudates or transferred to root-associated microorganisms. Surplus C is also produced under low moisture availability, low temperature, and high atmospheric CO2 concentrations, with similar below-ground effects. Many interactions among above- and below-ground ecosystem components can be parsimoniously explained by the production, distribution, and release of surplus C under conditions that limit plant growth.
  • Thrall, Peter H.; Laine, Anna-Liisa; Broadhurst, Linda M.; Bagnall, David J.; Brockwell, John (2011)
  • Vaario, Lu-Min; Sah, Shambhu Prasad; Norisada, Mariko; Narimatsu, Maki; Matsushita, Norihisa (2019)
    Tricholoma matsutake is an ectomycorrhizal (ECM) fungus capable of in vitro saprotrophic growth, but the sources of C and N used to generate sporocarps in vivo are not well understood. We examined natural abundance isotope data to investigate this phenomenon. For this purpose, C, N and their stable isotopes (13C, 15N) content of fungal sporocarps and their potential nutrient sources (i.e., foliage, litter, fine roots, wood, and soil) were investigated from two well-studied sites in Finland and Japan. Our results show that δ13C values of T. matsutake and other fungal groups are consistent with those of most studies, but a very high δ15N value (16.8‰ ± 2.3) is observed in T. matsutake. Such isotopic pattern of fungal δ15N suggests that matsutake has a greater proteolytic potential to digest chemically complex 15N-enriched organic matter and hydrophobic hyphae. This assumption is further supported by a significant and positive correlation between δ13Ccap–stipe and δ15Ncap–stipe exclusively in T. matsutake, which suggests common C and N sources (protein) possible for isotopically enriched cap. The 13C increase of caps relative to stipe presumably reflects greater contents of 13C-enriched protein than 13C-depleted chitin. We conclude that T. matsutake is a typical ECM fungus which obtains for its sporocarp development for both C and N from a common protein source (vs. photosynthetic carbon) present in soil organic matter.