Project description:Asexual development is fundamental to the ecology and lifestyle of filamentous fungi and can facilitate both plant and human infection. In the filamentous fungal genus Aspergillus, the production of asexual spores is primarily governed by the BrlA-AbaA-WetA central regulatory cascade. The final step in this cascade, which is controlled by the WetA protein, not only governs cellular development (i.e., the morphological differentiation of spores) but also ensures its coupling with chemical development (i.e., the coordinated production and deposition of diverse secondary metabolites, such as aflatoxins, into spores). While the wetA gene is conserved across the genus Aspergillus, the structure and degree of conservation of the BrlA-AbaA-WetA regulatory cascade and the broader wetA gene regulatory network (GRN) remain largely unknown. We carried out comparative transcriptome analyses between wetA null mutant and wild type (WT) asexual spores in three representative species spanning the diversity of the genus Aspergillus: the genetic model A. nidulans, the agricultural pest A. flavus, and the human pathogen A. fumigatus. We discovered that WetA regulates asexual sporulation in all three species via a negative feedback loop that represses BrlA, the cascade’s first step. Furthermore, ChIP-seq experiments in A. nidulans asexual spores suggest that WetA is a DNA-binding protein that interacts with a novel regulatory element, which we term the WetA Response Element (WRE). Interestingly, the WRE is found completely conserved in the non-coding region upstream of the wetA translation start site of many diverse Aspergillus genomes. In contrast, several global transcriptional regulators, most notably those in the velvet complex (veA, velB, and laeA) known to regulate the coupling between asexual development and production of secondary metabolites, show species-specific regulatory patterns. These results suggest that the BrlA-AbaA-WetA cascade’s regulatory role in cellular and chemical development of asexual spores is functionally conserved, but that the WetA-associated GRN has diverged during Aspergillus evolution. This entry is for the RNA-seq data.

Project description:Asexual development is fundamental to the ecology and lifestyle of filamentous fungi and can facilitate both plant and human infection. In the filamentous fungal genus Aspergillus, the production of asexual spores is primarily governed by the BrlA-AbaA-WetA central regulatory cascade. The final step in this cascade, which is controlled by the WetA protein, not only governs cellular development (i.e., the morphological differentiation of spores) but also ensures its coupling with chemical development (i.e., the coordinated production and deposition of diverse secondary metabolites, such as aflatoxins, into spores). While the wetA gene is conserved across the genus Aspergillus, the structure and degree of conservation of the BrlA-AbaA-WetA regulatory cascade and the broader wetA gene regulatory network (GRN) remain largely unknown. We carried out comparative transcriptome analyses between wetA null mutant and wild type (WT) asexual spores in three representative species spanning the diversity of the genus Aspergillus: the genetic model A. nidulans, the agricultural pest A. flavus, and the human pathogen A. fumigatus. We discovered that WetA regulates asexual sporulation in all three species via a negative feedback loop that represses BrlA, the cascade’s first step. Furthermore, ChIP-seq experiments in A. nidulans asexual spores suggest that WetA is a DNA-binding protein that interacts with a novel regulatory element, which we term the WetA Response Element (WRE). Interestingly, the WRE is found completely conserved in the non-coding region upstream of the wetA translation start site of many diverse Aspergillus genomes. In contrast, several global transcriptional regulators, most notably those in the velvet complex (veA, velB, and laeA) known to regulate the coupling between asexual development and production of secondary metabolites, show species-specific regulatory patterns. These results suggest that the BrlA-AbaA-WetA cascade’s regulatory role in cellular and chemical development of asexual spores is functionally conserved, but that the WetA-associated GRN has diverged during Aspergillus evolution. This entry is for the ChIP-seq data.

Project description:Filamentous fungi are important producers of enzymes and secondary metabolites in the biotech industry. A relatively new but highly promising fungus for industrial production is Thermothelomyces thermophilus, which is closely related to the model fungus Neurospora crassa. Nevertheless, to fully exploit the potential of T. thermophilus, a deeper understanding of its biology is necessary. A critical aspect of the filamentous fungal life cycle is the production of asexual spores (conidia), regulated by various stimuli, including nutrient availability. Under certain submerged fermentation conditions, several filamentous fungi produce conidia, which can be detrimental to product expression. In this study, we utilized RNA-seq to map transcriptomic changes during conidia production under submerged conditions in T. thermophilus. We found that the essential genes for conidiation in Aspergillus sp. and N. crassa, fluG and fluffy (fl), are not essential for conidiation in T. thermophilus. However, we identified a transcription factor, res1, whose deletion resulted in a complete loss of conidia production under fermentation conditions. This deletion also led to increased biomass production without increasing enzyme secretion. Notably, the deletion of res1 did not affect spore production on solid media. Differential gene expression analysis between the wild type and the res1 deletion mutant revealed that res1 regulates a broad range of cellular and metabolic processes, including MAPK and spore production pathways. Overexpression of res1 caused a severe growth defect and early conidia production compared to the wild type. Using ChIP-seq, we identified 35 potential target genes of res1, including known conidiation-related genes such as acon3, MAPK genes, and transcription factors like cpc1, as well as genes with unknown functions. Overall, we identified res1 to be obligatory for submerged conidia production and lay the foundation for further work on the T. thermophilus conidiation pathway and its applications.

Dataset Information

Crosstalk between Three Fungus-specific Transcription Factors, WetA, VosA, and VelB, in Asexual Spores of Aspergillus nidulans [RNA-seq]

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets