Project description:Enzymatic degradation of plant biomass requires a complex mixture of many different enzymes. Like most fungi, thermophilic Myceliophthora species therefore have a large set of enzymes targeting different linkages in plant polysaccharides. The majority of these enzymes have not been functionally characterized and their role in plant biomass degradation is unknown. This study describes a strategy using sexual crossing and screening with the thermophilic fungus Myceliophthora heterothallica to identify specific enzymes associated with improved sugar beet pulp saccharification.Two genetically diverse M. heterothallica strains CBS 203.75 and CBS 663.74 were used to generate progenies with improved growth on sugar beet pulp. One progeny, named SBP.F1.2.11, had a different genetic pattern from the parental strains, and had improved saccharification activity after growth on 3% sugar beet pulp. Exo-proteome analysis of progeny and parental strains after 7 days growth on sugar beet pulp showed that only 17 of the 133 secreted CAZy enzymes were more abundant in progeny SBP.F1.2.11. Particularly one enzyme belonging to the carbohydrate esterase family 5 (CE5) was more present in SBP.F1.2.11. This CE5-CBM1 enzyme, named as Axe1, was phylogenetically related to acetyl xylan esterases.
Project description:In this study, we compared the gene expression pattern of A. niger grown in liquid sugar beet pulp (SBP) at different time points, a by-product of the sugar industry that consists mainly of cellulose, xyloglucan, and pectin. Finally, we compared A. niger genetic response to liquid SBP to that of the same fungus when grown on solid SBP plates and polygalacturonic acid (PGA).
Project description:A. niger colony sections grown on spatially separated substrates (glucose, wheat bran, sugar beet pulp) using transcriptomics, proteomics and metabolomics showed high diversity and plasticity within the colony.
Project description:Saprotrophic fungi, such as Aspergillus niger, grow as mycelial colonies that are often considered uniform entities. To test this uniformity, we analyzed pie-slice sections of a colony grown on spatially separated substrates (glucose, wheat bran, sugar beet pulp) using transcriptomics, proteomics and metabolomics. The colony tuned its response to the local carbon source composition. Plant biomass degrading CAZymes and intracellular carbon catabolic enzymes were more abundant in parts of the colony containing the corresponding sugars. For example a stronger pectinolytic response was observed in the part of the colony grown on the pectin-rich sugar beet pulp. Our results argue against a situation in which small molecules are transported efficiently through the colony and favour high diversity within the fungal colony in natural biotopes, where the substrate is typically heterogeneous. It also demonstrates the high level of plasticity of A. niger in reponse to the composition of the prevailing lignocellulose.
Project description:We have performed a combined analysis of comparative genomics, proteomics and enzymology tests on seven Aspergillus species grown on wheat bran and sugar beet pulp to identify the various proteases and their productivities in Aspergilli.
Project description:Background: Sugar beet is an important root crop, accounting for 30 % of the sugar production worldwide. The long growing season make sugar beets exposed to a range of plant pathogens for longer periods than most other crops. Here, contrasting sugar beet genotypes were used for transcriptome analysis to reveal differential responses and new defense genes to Rhizoctonia solani, a soilborn fungal pathogen. Results: After curation of primary RNA-sequencing reads, 16,768 genes deriving from 36 samples composed of two susceptible and two resistant sugar beet genotypes, three time-points (0, two and five days post inoculation), each in three replicates were subjected for analysis. Among the elevated 217 transcripts at 2 dpi, three resistance-like genes (Bv4_088600_cumk, Bv8u_204980_frqg, and Bv_44840_iifo) were activated. By employing edgeR package statistics, 660 genes were significantly different (false discovery rate < 0.05) between resistant and susceptible genotypes in their response to R. solani inoculation. A combination of eukaryotic orthologous group assignments and gene ontology enrichment analyses, revealed three Bet v I/Major latex protein homologous genes (Bv7_162510_pymu, Bv7_162520_etow, Bv_27270_xeas) in the resistant genotypes after five days of fungal challenge. Co-expression network analysis of differentially expressed sugar beet genes further identified a MYB46 transcription factor, a plant disease resistance response protein (DRR206) and a flavonoid o-methyltransferase protein. MYB46 has a key function in secondary cell wall formation and exist as a singleton in the sugar beet genome. The genome of R. solani is enriched in cell wall degrading enzyme encoding genes and it is anticipated that they represent important virulence factors. Compared to Arabidopsis thaliana, sugar beet has 2.4-fold more carbohydrate esterases and particularly large numbers (26-fold) of auxiliary activity encoding genes whose function in cell wall biosynthesis is largely unknown. Conclusions: Based on components identified in this sugar beet transcript data set we conclude that defense responses to R. solani are attributed to a wide range of gene categories but functional information is missing to a large extent. This calls for careful integration to avoid negative side effects to obtain optimal combinations of these traits in order to reach the long-term goal of improved resistance in sugar beet.
Project description:Sugar beet (Beta vulgaris subsp. vulgaris) is an economically important crop and provides nearly one third of the global sugar production annually. The beet cyst nematode (BCN), Heterodera schachtii, causes major yield losses in sugar beet worldwide. The most effective and economic approach to control this nematode is growing tolerant or resistant cultivars. To identify candidate genes involved in susceptibility and resistance, the transcriptome of sugar beet and BCN in compatible and incompatible interactions at two time points, was studied using mRNA-seq. In total, 16 cDNA libraries were constructed and 442 691 707raw reads were obtained. In the compatible interaction, many alterations in phytohormone-related genes were detected. The effect of exogenous application of methyl jasmonate and ethephon was therefore investigated and the results revealed significant reduction of J2s infection and female development rates in treated susceptible plants. Our results revealed candidate genes putatively involved in the Hs1pro1-induced resistance, such as genes related to phenylpropanoid pathway, putative R genes and genes encoding F-box proteins, zinc finger and NAC transcription factors, ABC transporters, BURP and CYSTM proteins. Also, the transcriptome of BCN in the infected root samples was analyzed and several nematode effector genes were found. Our study is the first investigation of the transcriptome profile in the compatible and incompatible interactions between sugar beet and BCN.