Project description:Hemicellulose, the second most abundant plant biomass fraction after cellulose, is widely viewed as a potential feedstock for the production of liquid fuels and other value-added materials. Degradation of hemicellulose by filamentous fungi requires production of many different enzymes, which are induced by biopolymers or its derivatives and regulated mainly at the transcriptional level through transcription factors (TFs). Neurospora crassa has been shown to express and secrete plant cell wall associated enzymes. To better understand genes specifically associated with degradation of hemicellulose, we identified 353 genes by transcriptome analysis of N. crassa wild type strain grown on beechwood xylan. Exposure to xylan induces 9 of the 19 predicted hemicellulase genes. The xylanolytic phenotype of strains with deletions in genes identified from the secretome and transcriptome analysis of wild type showed that none were essential for growth on beechwood xylan. The transcription factor XlnR/Xyr1 in Aspergillus and Trichoderma species is considered to be the major transcriptional regulator of genes encoding both cellulases and hemicellulases. We identified a xlnR/xyr1 homolog in N. crassa, NCU06971, termed xlr-1 (xylanase regulator 1). Deletion of xlr-1 in N. crassa abolishes the growth on xylan and xylose, but growth on cellulose was indistinguishable from wild type. To determine regulatory mechanisms associated with hemicellulose degradation, we explored the transcriptional regulon of XLR-1 under xylose and xylanolytic versus cellulolytic conditions. XLR-1 regulated only some predicted hemicellulase genes in N. crassa and was required for a full induction of several cellulase genes. Hemicellulase gene expression was induced by a combination of release from carbon catabolite repression (CCR) and induction. However, in N. crassa, xlr-1 is subject to non-CRE-1 mediated CCR. This systematic analysis provides the similarities and differences of hemicellulose degradation and regulation mechanisms used by N. crassa in comparison to other filamentous fungi. Four-condition experiments (minimal medium, xylan medium,xylose and Avicel medium) of mutant strain(xlr-1) compared to wild type strain; Cy3 and Cy5 dye swap

Project description:Hemicellulose, the second most abundant plant biomass fraction after cellulose, is widely viewed as a potential feedstock for the production of liquid fuels and other value-added materials. Degradation of hemicellulose by filamentous fungi requires production of many different enzymes, which are induced by biopolymers or its derivatives and regulated mainly at the transcriptional level through transcription factors (TFs). Neurospora crassa has been shown to express and secrete plant cell wall associated enzymes. To better understand genes specifically associated with degradation of hemicellulose, we identified 353 genes by transcriptome analysis of N. crassa wild type strain grown on beechwood xylan. Exposure to xylan induces 9 of the 19 predicted hemicellulase genes. The xylanolytic phenotype of strains with deletions in genes identified from the secretome and transcriptome analysis of wild type showed that none were essential for growth on beechwood xylan. The transcription factor XlnR/Xyr1 in Aspergillus and Trichoderma species is considered to be the major transcriptional regulator of genes encoding both cellulases and hemicellulases. We identified a xlnR/xyr1 homolog in N. crassa, NCU06971, termed xlr-1 (xylanase regulator 1). Deletion of xlr-1 in N. crassa abolishes the growth on xylan and xylose, but growth on cellulose was indistinguishable from wild type. To determine regulatory mechanisms associated with hemicellulose degradation, we explored the transcriptional regulon of XLR-1 under xylose and xylanolytic versus cellulolytic conditions. XLR-1 regulated only some predicted hemicellulase genes in N. crassa and was required for a full induction of several cellulase genes. Hemicellulase gene expression was induced by a combination of release from carbon catabolite repression (CCR) and induction. However, in N. crassa, xlr-1 is subject to non-CRE-1 mediated CCR. This systematic analysis provides the similarities and differences of hemicellulose degradation and regulation mechanisms used by N. crassa in comparison to other filamentous fungi.

Project description:Background: Filamentous fungi produce large quantities of extracellular enzymes, such as cellulase and xylanase, to degrade polysaccharides derived from plant biomass. This process is controlled by a complex network of transcription factors (TFs). However, the regulatory mechanisms of cellulase and xylanase gene expression are poorly understood. Results: In this study, we reveal that the bZIP transcription factor Mthac-1 exerts dual regulatory effects on the production of cellulase and xylanase in the filamentous fungus Myceliophthora thermophila. The absence of Mthac-1 caused a reduction in cellulase and xylanase activities, as well as decreased protein secretion during the early phase of cultivation in Avicel medium, compared with the wild-type (WT) strain. However, in the middle and late stages, enzyme activities and protein secretion were noticeably enhanced by the deletion of Mthac-1. Additionally, the loss of Mthac-1 led to severe growth defects on sloid media containing various carbon sources, characterized by few hyphae branching and reduced conidiation. Real-time quantitative reverse transcription PCR (RT-qPCR) analysis showed that Mthac-1 dynamically regulates the expression of major cellulase genes. Furthermore, electrophoretic mobility shift assays (EMSAs) demonstrated that Mthac-1 directly binds to the promoter regions of the β-glucosidase gene bgl1 (MYCTH_66804), cellobiohydrolase gene cbh1 (MYCTH_109566), endoglucanase gene egl2 (MYCTH_86753), xylanase gene xyn1 (MYCTH_112050), and the crucial regulatory gene xyr1 (MYCTH_2310145), exhibiting higher binding affinity for xyn1 and xyr1. Notably, comparative transcriptomic analysis indicated that Mthac-1 also plays an important role in the expression of 26S proteasome-encoding genes under cellulolytic conditions. Conclusions: Mthac-1 functions as a dual regulator of cellulase and xylanase production by regulating the expression of major cellulase and xylanase genes, as well as the key transactivator gene Mtxyr1, via direct promoter binding. Our work provides new insights into the regulatory mechanisms underlying cellulase and xylanase gene expression and has potential applications in fungal strain engineering in biorefinery industries.

Project description:Myceliophthora thermophila, a thermophilic fungus, has been utilized to produce industrially important enzymes in biorefineries. In filamentous fungi, the mechanisms underlying cellulase and xylanase expression have been explored, which uncovered the complex networks controlled by numerous transcription factors (TFs). However, the TFs regulating cellulase and xylanase gene expression and production remain unclear in M. thermophila. Here, we identified and characterized a novel cellulase and xylanase regulator MtFKH1 (MYCTH_2307931) in M. thermophila through comparative transcriptomic and genetic analyses. Comparative transcriptome analyses of M. thermophila grown on Avicel and glucose screened eight potential transcription factor encoding genes and five of them were successfully deleted by newly developed CRISPR/Cas9 system, which caused the identification of a forkhead TF MtFKH1. The disruption of Mtfkh1 remarkably elevated cellulolytic and xylanolytic enzyme activities, whereas the overexpression of Mtfkh1 led to considerable decrease in cellulase and xylanase production in M. thermophila cultivated on Avicel. Loss of Mtfkh1 also exhibited an impairment in sporulation but normal mycelia growth compared with WT. Real-time quantitative reverse transcription PCR (RT-qPCR) showed that MtFKH1 regulated the expression of essential cellulase and xylanase genes, and electrophoretic mobility shift assays (EMSAs) demonstrated that MtFKH1 could specifically bound to the promoter regions of genes encoding β-glucosidase (bgl1/MYCTH_66804), cellobiohydrolase (cbh1/MYCTH_109566), and xylanase (xyn1/MYCTH_112050). Further DNase I footprinting analysis identified binding motif of MtFKH1 in the upstream region of Mtbgl1, which exhibited strongest binding affinity. Finally, transcriptomic profiling and Gene Ontology (GO) enrichment analyses of Mtfkh1 deletion mutant revealed that the regulon of MtFKH1 were significantly prevalent in hydrolase activity (acting on glycosyl bonds), polysaccharide binding, and carbohydrate metabolic process functional categories. These findings enlarge our knowledge of how forkhead transcription factor regulate lignocellulose degradation and provide a novel target for engineering of fungal cell factories with the hyperproduction of cellulases and xylanases.

			Action	DRS
	4798_01_3inj_newdb_moko_Lumos_231212_FAIMS_06_07_08.msf	Msf
	4798_02_3inj_newdb_moko_Lumos_231212_FAIMS_11_12_13.msf	Msf
	4798_03_3inj_newdb_moko_Lumos_231212_FAIMS_16_17_18.msf	Msf
	4798_07_newdb_illi_3inj_Lumos_231212_FAIMS_21_22_23.msf	Msf
	4798_08_3inj_newdb_illi_Lumos_231212_FAIMS_26_27_28.msf	Msf

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Genomic and Secretomic analysis of Blastobotrys yeasts reveal key xylanases for biomass decomposition

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Genomic and secretomic analyses of Blastobotrys yeasts reveal key xylanases for biomass decomposition.

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