Project description:Brown rot fungi have great potential in biorefinery wood conversion systems, because they are the primary wood decomposers in coniferous forests and have an efficient lignocellulose degrading system. Their initial wood degradation mechanism is thought to consist of an oxidative radical-based system that acts sequentially with an enzymatic saccharification system, but the complete molecular mechanism of this system has not yet been elucidated. Some studies have shown that wood degradation mechanisms of brown rot fungi have diversity in their substrate selectivity. Gloeophyllum trabeum, one of the most studied brown rot species, has broad substrate selectivity and even can degrade some grasses. However, the basis for this broad substrate specificity is poorly understood. In this study, we performed RNA-seq analyses on G. trabeum grown on media containing glucose, cellulose, or Japanese cedar (Cryptomeria japonica) as the sole carbon source. Beyond the gene expression on glucose, 1129 genes were upregulated on cellulose and 1516 genes were upregulated on cedar. Carbohydrate Active enZyme (CAZyme) genes upregulated on cellulose and cedar media by G. trabeum included GH12, GH131, CE1, AA3_1, AA3_2, AA3_4 and AA9, which is a newly reported expression pattern for brown rot fungi. The upregulation of both terpene synthase and cytochrome P450 genes on cedar media suggests the potential importance of these genes in the production of secondary metabolites associated with the chelator-mediated Fenton reaction. These results provide new insights into the inherent wood degradation mechanism of G. trabeum and the diversity of brown rot mechanisms.

2020-08-05 | GSE155681 | GEO

Capturing early gene expression dynamics during wood decay by brown rot fungus Rhodonia placenta

Project description:Brown rot fungi dominate wood decomposition in coniferous forests, and their carbohydrate-selective mechanisms are of commercial interest. Brown rot was recently described as a two-step, sequential mechanism orchestrated by fungi using differentially expressed genes (DEGs) and consisting of oxidation via reactive oxygen species (ROS) followed by enzymatic saccharification. There have been indications, however, that the initial oxidation step, itself, might require induction. To capture this early gene regulation event, here we integrated fine-scale cryo-sectioning with whole transcriptome sequencing to dissect gene expression at the single hyphal cell scale (tens of μm). We improved spatial resolution 50x, relative to previous work, and we were able to capture the activity of the first 100 μm of hyphal front growth by Rhodonia placenta in aspen wood. By comparing the first 100-μm section with a 100-μm from a later decay stage, it was clear that the early decay period was dominated by delayed gene expression patterns as the fungus ramped up its mechanism. These delayed DEGs included many genes implicated in ROS pathways (lignocellulose oxidation, LOX) that were previously and incorrectly assumed to be constitutively expressed. However, this delayed pattern was not universal, with a handful of genes upregulated immediately at the hyphal front.

2022-03-01 | GSE193915 | GEO

Genetic determinants of endophytism in the Arabidopsis root mycobiome

Project description:Roots of Arabidopsis thaliana do not engage in symbiotic association with mycorrhizal fungi but host taxonomically diverse fungal communities that influence health and disease states. We sequenced the genomes of 41 isolates representative of the A. thaliana root mycobiota for comparative analysis with 79 other plant-associated fungi. We report that root mycobiota members evolved from ancestors having diverse lifestyles and retained diverse repertoires of plant cell wall-degrading enzymes (PCWDEs) and effector-like small secreted proteins. We identified a set of 84 gene families predicting best endophytism, including families encoding PCWDEs acting on xylan (GH10) and cellulose (AA9). These genes also belong to a core transcriptional response induced by phylogenetically-distant mycobiota members in A. thaliana roots. Recolonization experiments with individual fungi indicated that strains with detrimental effects in mono-association with the host not only colonize roots more aggressively than those with beneficial activities but also dominate in natural root samples. We identified and validated the pectin degrading enzyme family PL1_7 as a key component linking aggressiveness of endophytic colonization to plant health.

2021-11-03 | GSE169629 | GEO

root associated fungus metagenome

Project description:Community dynamics of arbuscular mycorrhizal fungi in two radiocesium degradation lands due to the Fukushima-Daiichi Nuclear disaster in Japan

| PRJDB6724 | ENA

root associated fungus metagenome

Project description:Arbuscular mycorrhizal fungi communities in the roots of the invasive Nicotiana glauca and co-occurring native plants

| PRJNA521301 | ENA

root associated fungus metagenome of Lotus japonicus

Project description:Fungi living in roots and rhizosphere of Lotus japonicus Metagenome

| PRJNA489990 | ENA