Project description:Fungal necromass in soil represents the stable carbon pools. While fungi are known to decompose fungal necromass, how fungi decomopose melanin, remains poorly understood. Recently, Trichoderma species was found to be one of the most commonly associated fungi in soil, we have used a relevant fungal species, Trichoderma reesei, to characterized Genes involved in the decomposition of melanized and non-melanized necromass from Hyaloscypha bicolor.
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: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 the strain Pseudomonas fluorescens Pf29Arp 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 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 of two beneficial, and neutral soil bacteria during their interactions in vitro. We performed nine hybridizations (macroarray) with samples derived from Laccaria bicolor cultivated alone (3 biological replicates), with P. fluorescens BBc6R8 (3 biological replicates) and with Pf29Arp (3 biological replicates)
Project description:Decomposition of soil organic matter in forest soils is thought to be controlled by the activity of saprotrophic fungi, while biotrophic fungi including ectomycorrhizal fungi act as vectors for input of plant carbon. The limited decomposing ability of ectomycorrhizal fungi is supported by recent findings showing that they have lost many of the genes that encode hydrolytic plant cell-wall degrading enzymes in their saprophytic ancestors. Nevertheless, here we demonstrate that ectomycorrhizal fungi representing at least four origins of symbiosis have retained significant capacity to degrade humus-rich litter amended with glucose. Spectroscopy showed that this decomposition involves an oxidative mechanism and that the extent of oxidation varies with the phylogeny and ecology of the species. RNA-Seq analyses revealed that the genome-wide set of expressed transcripts during litter decomposition has diverged over evolutionary time. Each species expressed a unique set of enzymes that are involved in oxidative lignocellulose degradation by saprotrophic fungi. A comparison of closely related species within the Boletales showed that ectomycorrhizal fungi oxidized litter material as efficiently as brown-rot saprotrophs. The ectomycorrhizal species within this clade exhibited more similar decomposing mechanisms than expected from the species phylogeny in concordance with adaptive evolution occurring as a result of similar selection pressures. Our data shows that ectomycorrhizal fungi are potential organic matter decomposers, yet not saprotrophs. We suggest that the primary function of this decomposing activity is to mobilize nutrients embedded in organic matter complexes and that the activity is driven by host carbon supply. Comparative transcriptomics of ectomycorrhizal (ECM) versus brown-rot (BR) fungi while degrading soil-organic matter
