Project description:This SuperSeries is composed of the following subset Series: GSE27941: Lignocellulose-induced regulation of Phanaerochaete chrysosporium genes GSE29656: Postia placenta MAD-698 gene expression in ball-milled aspen or ball-milled pine medium Refer to individual Series
Project description:Transcript profiles of Postia placenta grown on media containing ball-milled aspen or ball-milled pine as the sole carbon source were analyzed. Array design was based on the DoE's Joint Genome Institute's gene models for P. placenta version 1. The research goal is to identtify genes essential for cellulose depolymerization.
Project description:Transcript profiles of Postia placenta grown on media containing ball-milled aspen or ball-milled pine as the sole carbon source were analyzed. Array design was based on the DoE's Joint Genome Institute's gene models for P. placenta version 1. The research goal is to identtify genes essential for cellulose depolymerization. From a data set of 12,438 unique alleles, each NimbleGen (Madison, WI) array featured 10 unique 60mers per gene, all in triplicate. The dataset was manually annotated to include only the ‘best allelic model’ among CAZY-encoding genes. Total RNA was purified from medium containing ball-milled aspen or ball-milled pine as the sole carbon source. Three biological replicates per medium were used (6 separate arrays). RNA was converted to double-strand cDNA and labeled with the Cy3 fluorophore sample for hybridization to the Postia placenta MAD-698 whole genome expression array by Roche NimbleGen (Iceland). In brief, 10ug of total RNA was incubated with 1X first strand buffer, 10 mM DTT, 0.5mM dNTPs, 100 pM oligo T7 d(T)24 primer, and 200 units of SuperScript II (Invitrogen) for 60 min at 42°C. Second strand cDNA was synthesized by incubation with 1X second strand buffer, 0.2mM dNTPs, 0.07 units per ul DNA ligase (Invitrogen), 0.27 units per ul DNA polymerase I (Invitrogen), 0.013 units per ul RNase H (Invitrogen), at 16°C for 2 hours. Immediately following, 10 units T4 DNA polymerase (Invitrogen) was added for additional 5 minute incubation at 16°C. Double-stranded cDNA was treated with 27ng/ul of RNase A (EpiCenter Technologies) for 10 minutes at 37°C. Treated cDNA was purified using an equal volume of phenol:chloroform:isoamyl alcohol (Ambion), ethanol precipitated, washed with 80% ethanol, and resuspended in 20ul water. One ug of each cDNA sample was amplified and labeled with 1 unit per ul of Klenow Fragment (New England BioLabs) and 1 O.D unit of Cy3 fluorophore (TriLink Biotechnologies, Inc.) for 2 hours at 37°C. Array hybridization was carried out with 6ug of labeled cDNA suspended in NimbleGen hybridization solution for 17 hours at 42°C.
Project description:Cellulose degradation by brown rot fungi, such as Postia placenta, is poorly understood relative to the phylogenetically related white rot basidiomycete, Phanerochaete chrysosporium. To elucidate the number, structure, and regulation of genes involved in lignocellulosic cell wall attack, secretome and transcriptome analyses were performed on both wood decay fungi cultured for 5 days in media containing ball-milled aspen or glucose as the sole carbon source. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a total of 67 and 79 proteins were identified in the extracellular fluids of P. placenta and P. chrysosporium cultures, respectively. Viewed together with transcript profiles, P. chrysosporium employs an array of extracellular glycosyl hydrolases to simultaneously attack cellulose and hemicelluloses. In contrast, under these same conditions, P. placenta secretes an array of hemicellulases but few potential cellulases. The two species display distinct expression patterns for oxidoreductase-encoding genes. In P. placenta, these patterns are consistent with an extracellular Fenton system and include the upregulation of genes involved in iron acquisition, in the synthesis of low-molecular-weight quinones, and possibly in redox cycling reactions.
Project description:Identification of specific genes and enzymes involved in conversion of lignocellulosics from an expanding number of potential feedstocks is of growing interest to bioenergy process development. The basidiomycetous wood decay fungi Phanerochaete chrysosporium and Postia placenta are promising in this regard because they are able to utilize a wide range of simple and complex carbon compounds. However, systematic comparative studies with different woody substrates have not been reported. To address this issue, we examined gene expression of these fungi colonizing aspen (Populus grandidentata) and pine (Pinus strobus). Transcript levels of genes encoding extracellular glycoside hydrolases, thought to be important for hydrolytic cleavage of hemicelluloses and cellulose, showed little difference for P. placenta colonizing pine versus aspen as the sole carbon source. However, 164 genes exhibited significant differences in transcript accumulation for these substrates. Among these, 15 cytochrome P450s were upregulated in pine relative to aspen. Of 72 P. placenta extracellular proteins identified unambiguously by mass spectrometry, 52 were detected while colonizing both substrates and 10 were identified in pine but not aspen cultures. Most of the 178 P. chrysosporium glycoside hydrolase genes showed similar transcript levels on both substrates, but 13 accumulated >2-fold higher levels on aspen than on pine. Of 118 confidently identified proteins, 31 were identified in both substrates and 57 were identified in pine but not aspen cultures. Thus, P. placenta and P. chrysosporium gene expression patterns are influenced substantially by wood species. Such adaptations to the carbon source may also reflect fundamental differences in the mechanisms by which these fungi attack plant cell walls.
Project description:UnlabelledIdentification of the specific genes and enzymes involved in the fungal degradation of lignocellulosic biomass derived from feedstocks with various compositions is essential to the development of improved bioenergy processes. In order to elucidate the effect of substrate composition on gene expression in wood-rotting fungi, we employed microarrays based on the annotated genomes of the brown- and white-rot fungi, Rhodonia placenta (formerly Postia placenta) and Phanerochaete chrysosporium, respectively. We monitored the expression of genes involved in the enzymatic deconstruction of the cell walls of three 4-year-old Populus trichocarpa (poplar) trees of genotypes with distinct cell wall chemistries, selected from a population of several hundred trees grown in a common garden. The woody substrates were incubated with wood decay fungi for 10, 20, and 30 days. An analysis of transcript abundance in all pairwise comparisons highlighted 64 and 84 differentially expressed genes (>2-fold, P < 0.05) in P. chrysosporium and P. placenta, respectively. Cross-fungal comparisons also revealed an array of highly differentially expressed genes (>4-fold, P < 0.01) across different substrates and time points. These results clearly demonstrate that gene expression profiles of P. chrysosporium and P. placenta are influenced by wood substrate composition and the duration of incubation. Many of the significantly expressed genes encode "proteins of unknown function," and determining their role in lignocellulose degradation presents opportunities and challenges for future research.ImportanceThis study describes the variation in expression patterns of two wood-degrading fungi (brown- and white-rot fungi) during colonization and incubation on three different naturally occurring poplar substrates of differing chemical compositions, over time. The results clearly show that the two fungi respond differentially to their substrates and that several known and, more interestingly, currently unknown genes are highly misregulated in response to various substrate compositions. These findings highlight the need to characterize several unknown proteins for catalytic function but also as potential candidate proteins to improve the efficiency of enzymatic cocktails to degrade lignocellulosic substrates in industrial applications, such as in a biochemically based bioenergy platform.
Project description:Transcript profiles of Phanerochaete chrysosporium grown on different substrates were analyzed. Array design based on the DoE's Joint Genome Institute's v2.1 annotation. Goal is to define genes involved in cellulose degradation. Keywords: gene expression under different culture conditions