Project description:Ectomycorrhizal fungi are dependent on host trees for carbon supply. In return ectomycorrhizal fungi supply trees with water and nutrients. It is known that when ectomycorrhizal fungi have exploited a nutrient rich patch in soil, the carbon allocation to mycelia in that patch is reduced, with the consequence of mycelia dying, but less is known of the dynamics of this senescence. We cultivated the ectomycorrhizal fungus Paxillus involutus in an axenic system. We collected growth and transcriptome data at different stages of carbon starvation during fungal growth. Carbon starvation induced a decrease in fungal biomass, which coincided with the release of NH4+ and the expression of genes connected with autophagy as well as protease and chitinase activity. Monoaromatic compounds, chitin and protease activity was detected in the liquid growth media during carbon starvation. The exudation of NH4+ and increase of monoaromatic compound during C starvation suggests senescence and autolysis of P. involutus. Together with the upregulation of genes involved in autophagy, chitinase and endopeptidase activity this points towards a controlled senescence including recycling of compounds originating from the fungi. Reduced C allocation to ectomycorrhizal mycelia in recently depleted nutrient patches in forest soils must be of ubiquitous nature. Understanding the mechanisms during exploitation of nutrients by ectomycorrhizal fungi is of great importance for understanding carbon and nutrient dynamics in forest soils. This is to our knowledge the first study describing the carbon starvation response in an ectomycorrhizal fungus.
Project description:Ectomycorrhizal fungi are dependent on host trees for carbon supply. In return ectomycorrhizal fungi supply trees with water and nutrients. It is known that when ectomycorrhizal fungi have exploited a nutrient rich patch in soil, the carbon allocation to mycelia in that patch is reduced, with the consequence of mycelia dying, but less is known of the dynamics of this senescence. We cultivated the ectomycorrhizal fungus Paxillus involutus in an axenic system. We collected growth and transcriptome data at different stages of carbon starvation during fungal growth. Carbon starvation induced a decrease in fungal biomass, which coincided with the release of NH4+ and the expression of genes connected with autophagy as well as protease and chitinase activity. Monoaromatic compounds, chitin and protease activity was detected in the liquid growth media during carbon starvation. The exudation of NH4+ and increase of monoaromatic compound during C starvation suggests senescence and autolysis of P. involutus. Together with the upregulation of genes involved in autophagy, chitinase and endopeptidase activity this points towards a controlled senescence including recycling of compounds originating from the fungi. Reduced C allocation to ectomycorrhizal mycelia in recently depleted nutrient patches in forest soils must be of ubiquitous nature. Understanding the mechanisms during exploitation of nutrients by ectomycorrhizal fungi is of great importance for understanding carbon and nutrient dynamics in forest soils. This is to our knowledge the first study describing the carbon starvation response in an ectomycorrhizal fungus. A one-chip study (data from 12 subarrays collected from a 12-plex Nimblegen microarray (ID 527890) using total RNA recovered from three separate glass-bead cultures of Paxillus involutus (ATCC200175) grown on Minimum Melin Norkrans medium (MMN) amended with ammonium (C/N ratio 3) and harvested at different times of carbon starvation.)
Project description:Many trees form ectomycorrhizal symbiosis with fungi. During symbiosis, the tree roots supply sugar to the fungi in exchange for nitrogen, and this process is critical for the nitrogen and carbon cycles in forest ecosystems. However, the extents to which ectomycorrhizal fungi can liberate nitrogen and modify the soil organic matter and the mechanisms by which they do so remain unclear since they have lost many enzymes for litter decomposition that were present in their free-living, saprotrophic ancestors. Using time-series spectroscopy and transcriptomics, we examined the ability of two ectomycorrhizal fungi from two independently evolved ectomycorrhizal lineages to mobilize soil organic nitrogen. Both species oxidized the organic matter and accessed the organic nitrogen. The expression of those events was controlled by the availability of glucose and inorganic nitrogen. Despite those similarities, the decomposition mechanisms, including the type of genes involved as well as the patterns of their expression, differed markedly between the two species. Our results suggest that in agreement with their diverse evolutionary origins, ectomycorrhizal fungi use different decomposition mechanisms to access organic nitrogen entrapped in soil organic matter. The timing and magnitude of the expression of the decomposition activity can be controlled by the below-ground nitrogen quality and the above-ground carbon supply.
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and of two beneficial, and neutral soil bacteria during their interactions in vitro.
Project description:The aim of this analysis was to better understand the complex symbiotic stage of Tuber melanosporum by combining the use of laser capture microdissection and microarray gene expression analysis. We isolated the fungal/soil (i.e. the mantle) and the fungal/plant (i.e. the Hartig net) interfaces from transverse sections of T. melanosporum/Corylus avellana ectomycorrhizas and identified the transcriptional landscape associated with each compartment. We compared these data to the transcriptome of ectomycorrhizal root tips, free-living mycelium and fruiting bodies of Tuber melanosporum (Series GSE17529).
Project description:The majority of trees live in association with symbiotic fungi, which facilitate their access to soil nutrients. The ectomycorrhizal symbiosis represents a complex biological system involving multifaceted interactions between the two partners. The establishment of the symbiosis depends on various conditions (e.g. climate), but also on the genetic traits of the partners. To evaluate the impact of the genetic predisposition on the development and functioning of ectomycorrhizas, we compared the transcriptome of roots from Populus trichocarpa and Populus deltoides colonized with Laccaria bicolor.
2011-01-15 | GSE26416 | GEO
Project description:Ectomycorrhizal fungal communities associated with urban Carpinus betulus trees
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and one detrimental bacterial strain during their interactions in vitro.
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and one detrimental bacterial strain during their interactions in vitro.
Project description:In order to get insights into the ability of ectomycorrhizal fungi to perceive their biotic environment as well as into the mechanisms of the interactions between ectomycorrhizal fungi and soil bacteria, we analysed the transcriptomic response of the ectomycorrhizal fungus L. bicolor and the strain Pseudomonas fluorescens Pf29Arp during their interactions in vitro.
