Apc.LaeA and Apc.VeA of the velvet complex govern secondary metabolism and morphological development in the echinocandin-producing fungus Aspergillus pachycristatus

ABSTRACT In filamentous fungi, asexual development involves cellular differentiation and metabolic remodeling leading to the formation of intact asexual spores. The development of asexual spores (conidia) in Aspergillus is precisely coordinated by multiple transcription factors (TFs), including VosA, VelB, and WetA. Notably, these three TFs are essential for the structural and metabolic integrity, i.e., proper maturation, of conidia in the model fungus Aspergillus nidulans. To gain mechanistic insight into the complex regulatory and interdependent roles of these TFs in asexual sporogenesis, we carried out multi-omics studies on the transcriptome, protein-DNA interactions, and primary and secondary metabolism employing A. nidulans conidia. RNA sequencing and chromatin immunoprecipitation sequencing analyses have revealed that the three TFs directly or indirectly regulate the expression of genes associated with heterotrimeric G-protein signal transduction, mitogen-activated protein (MAP) kinases, spore wall formation and structural integrity, asexual development, and primary/secondary metabolism. In addition, metabolomics analyses of wild-type and individual mutant conidia indicate that these three TFs regulate a diverse array of primary metabolites, including those in the tricarboxylic acid (TCA) cycle, certain amino acids, and trehalose, and secondary metabolites such as sterigmatocystin, emericellamide, austinol, and dehydroaustinol. In summary, WetA, VosA, and VelB play interdependent, overlapping, and distinct roles in governing morphological development and primary/secondary metabolic remodeling in Aspergillus conidia, leading to the production of vital conidia suitable for fungal proliferation and dissemination. IMPORTANCE Filamentous fungi produce a vast number of asexual spores that act as efficient propagules. Due to their infectious and/or allergenic nature, fungal spores affect our daily life. Aspergillus species produce asexual spores called conidia; their formation involves morphological development and metabolic changes, and the associated regulatory systems are coordinated by multiple transcription factors (TFs). To understand the underlying global regulatory programs and cellular outcomes associated with conidium formation, genomic and metabolomic analyses were performed in the model fungus Aspergillus nidulans. Our results show that the fungus-specific WetA/VosA/VelB TFs govern the coordination of morphological and chemical developments during sporogenesis. The results of this study provide insights into the interdependent, overlapping, or distinct genetic regulatory networks necessary to produce intact asexual spores. The findings are relevant for other Aspergillus species such as the major human pathogen Aspergillus fumigatus and the aflatoxin producer Aspergillus flavus.

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Hormonal control by A-factor of morphological development and secondary metabolism in Streptomyces

Proceedings of the Japan Academy Series B ◽

10.2183/pjab.83.277 ◽

2007 ◽

Vol 83 (9/10) ◽

pp. 277-295 ◽

Cited By ~ 66

Author(s):

Sueharu HORINOUCHI ◽

Teruhiko BEPPU

Keyword(s):

Secondary Metabolism ◽

Hormonal Control ◽

Morphological Development

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Pleiotropic Control of Secondary Metabolism and Morphological Development by KsbC, a Butyrolactone Autoregulator Receptor Homologue in Kitasatospora setae

Applied and Environmental Microbiology ◽

10.1128/aem.02355-12 ◽

2012 ◽

Vol 78 (22) ◽

pp. 8015-8024 ◽

Cited By ~ 23

Author(s):

Aiyada Aroonsri ◽

Shigeru Kitani ◽

Junko Hashimoto ◽

Ikuko Kosone ◽

Miho Izumikawa ◽

...

Keyword(s):

Secondary Metabolism ◽

Aerial Mycelium ◽

Biosynthetic Gene Cluster ◽

Morphological Development ◽

Content Type ◽

Streptomyces Virginiae ◽

Enhanced Production ◽

Regulatory Systems ◽

Autoregulator Receptor

ABSTRACTThe γ-butyrolactone autoregulator signaling cascades have been shown to control secondary metabolism and/or morphological development among manyStreptomycesspecies. However, the conservation and variation of the regulatory systems among actinomycetes remain to be clarified. The genome sequence ofKitasatospora setae, which also belongs to the familyStreptomycetaceaecontaining the genusStreptomyces, has revealed the presence of three homologues of the autoregulator receptor: KsbA, which has previously been confirmed to be involved only in secondary metabolism; KsbB; and KsbC. We describe here the characterization ofksbC, whose regulatory cluster closely resembles theStreptomyces virginiae barAlocus responsible for the autoregulator signaling cascade. Deletion of the geneksbCresulted in lowered production of bafilomycin and a defect of aerial mycelium formation, together with the early and enhanced production of a novel β-carboline alkaloid named kitasetaline. A putative kitasetaline biosynthetic gene cluster was identified, and its expression in a heterologous host led to the production of kitasetaline together with JBIR-133, the production of which is also detected in theksbCdisruptant, and JBIR-134 as novel β-carboline alkaloids, indicating that these genes were biosynthetic genes for β-carboline alkaloid and thus are the first such genes to be discovered in bacteria.

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Genome-Wide Chromatin Immunoprecipitation Sequencing Analysis of the Penicillium chrysogenum Velvet Protein PcVelA Identifies Methyltransferase PcLlmA as a Novel Downstream Regulator of Fungal Development

mSphere ◽

10.1128/msphere.00149-16 ◽

2016 ◽

Vol 1 (4) ◽

Cited By ~ 7

Author(s):

Kordula Becker ◽

Sandra Ziemons ◽

Katharina Lentz ◽

Michael Freitag ◽

Ulrich Kück

Keyword(s):

Next Generation Sequencing ◽

Secondary Metabolism ◽

Filamentous Fungi ◽

Chromatin Immunoprecipitation ◽

Next Generation ◽

Content Type ◽

Major Interest ◽

Lactam Antibiotic ◽

Velvet Complex ◽

Generation Sequencing

ABSTRACT Filamentous fungi are of major interest for biotechnological and pharmaceutical applications. This is due mainly to their ability to produce a wide variety of secondary metabolites, many of which are relevant as antibiotics. One of the most prominent examples is penicillin, a β-lactam antibiotic that is produced on the industrial scale by fermentation of P. chrysogenum. In recent years, the multisubunit protein complex velvet has been identified as one of the key regulators of fungal secondary metabolism and development. However, until recently, only a little has been known about how velvet mediates regulation at the molecular level. To address this issue, we performed ChIP-seq (chromatin immunoprecipitation in combination with next-generation sequencing) on and follow-up analysis of PcVelA, the core component of the velvet complex in P. chrysogenum. We demonstrate direct involvement of velvet in transcriptional control and present the putative methyltransferase PcLlmA as a new downstream factor and interaction partner of PcVelA. Penicillium chrysogenum is the sole industrial producer of the β-lactam antibiotic penicillin, which is the most commonly used drug for treating bacterial infections. In P. chrysogenum and other filamentous fungi, secondary metabolism and morphogenesis are controlled by the highly conserved multisubunit velvet complex. Here we present the first chromatin immunoprecipitation next-generation sequencing (ChIP-seq) analysis of a fungal velvet protein, providing experimental evidence that a velvet homologue in P. chrysogenum (PcVelA) acts as a direct transcriptional regulator at the DNA level in addition to functioning as a regulator at the protein level in P. chrysogenum, which was previously described. We identified many target genes that are related to processes known to be dependent on PcVelA, e.g., secondary metabolism as well as asexual and sexual development. We also identified seven PcVelA target genes that encode putative methyltransferases. Yeast two-hybrid and bimolecular fluorescence complementation analyses showed that one of the putative methyltransferases, PcLlmA, directly interacts with PcVelA. Furthermore, functional characterization of PcLlmA demonstrated that this protein is involved in the regulation of conidiosporogenesis, pellet formation, and hyphal morphology, all traits with major biotechnological relevance. IMPORTANCE Filamentous fungi are of major interest for biotechnological and pharmaceutical applications. This is due mainly to their ability to produce a wide variety of secondary metabolites, many of which are relevant as antibiotics. One of the most prominent examples is penicillin, a β-lactam antibiotic that is produced on the industrial scale by fermentation of P. chrysogenum. In recent years, the multisubunit protein complex velvet has been identified as one of the key regulators of fungal secondary metabolism and development. However, until recently, only a little has been known about how velvet mediates regulation at the molecular level. To address this issue, we performed ChIP-seq (chromatin immunoprecipitation in combination with next-generation sequencing) on and follow-up analysis of PcVelA, the core component of the velvet complex in P. chrysogenum. We demonstrate direct involvement of velvet in transcriptional control and present the putative methyltransferase PcLlmA as a new downstream factor and interaction partner of PcVelA.

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Hülle-cell-mediated protection of fungal reproductive and overwintering structures against fungivorous animals

10.1101/2021.03.14.435325 ◽

2021 ◽

Author(s):

Li Liu ◽

Benedict Dirnberger ◽

Oliver Valerius ◽

Enikő Fekete-Szücs ◽

Rebekka Harting ◽

...

Keyword(s):

Stem Cells ◽

Secondary Metabolism ◽

Sexual Development ◽

Biosynthetic Pathway ◽

Fruiting Bodies ◽

Antifeedant Activity ◽

Multipotent Stem Cells ◽

Reproductive Structures ◽

Velvet Complex

AbstractFungal Hülle cells with nuclear storage and developmental backup functions are reminiscent of multipotent stem cells. In the soil, Hülle cells nurse the overwintering fruiting bodies of Aspergillus nidulans. The genome of A. nidulans harbors genes for the biosynthesis of xanthones. We show that enzymes and metabolites of this biosynthetic pathway accumulate in Hülle cells under the control of the regulatory velvet complex, which coordinates development and secondary metabolism. Deletion strains blocked in the conversion of anthraquinones to xanthones are delayed in maturation and growth of fruiting bodies. Xanthones are not required for sexual development but exert antifeedant effects on fungivorous animals such as springtails and woodlice. These findings reveal a novel role of Hülle cells in establishing secure niches for A. nidulans by accumulating metabolites with antifeedant activity that protect reproductive structures from animal predators.

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Faculty Opinions recommendation of Suppressor mutagenesis identifies a velvet complex remediator of Aspergillus nidulans secondary metabolism.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.5674981.5649086 ◽

2010 ◽

Author(s):

Joseph Strauss

Keyword(s):

Secondary Metabolism ◽

Aspergillus Nidulans ◽

Velvet Complex

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Biosynthesis of -butyrolactone autoregulators that switch on secondary metabolism and morphological development in Streptomyces

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0607472104 ◽

2007 ◽

Vol 104 (7) ◽

pp. 2378-2383 ◽

Cited By ~ 132

Author(s):

J.-y. Kato ◽

N. Funa ◽

H. Watanabe ◽

Y. Ohnishi ◽

S. Horinouchi

Keyword(s):

Secondary Metabolism ◽

Morphological Development

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The A-factor regulatory cascade that leads to morphological development and secondary metabolism in Streptomyces

Biofilms ◽

10.1017/s1479050504001462 ◽

2004 ◽

Vol 1 (4) ◽

pp. 319-328 ◽

Cited By ~ 10

Author(s):

Y. Ohnishi ◽

S. Horinouchi

Keyword(s):

Dna Binding ◽

Secondary Metabolism ◽

Receptor Protein ◽

Binding Motif ◽

Morphological Development ◽

Dependent Manner ◽

Terminal Portion ◽

Factor Binding ◽

Regulatory Cascade ◽

Chemical Signalling

A-factor (2-isocapryloyl-3R-hydroxymethyl-γ-butyrolactone) is a chemical signalling molecule, or microbial hormone, that triggers aerial mycelium formation and secondary metabolism in Streptomyces griseus. A-factor pro- duced in a growth-dependent manner switches on the transcription of adpA, encoding a transcriptional activator, by binding to ArpA, the A-factor receptor protein, which has bound to the adpA promoter, and dissociating the bound ArpA from the DNA. AdpA then activates a number of genes of various functions required for morphological development and secondary metabolism, forming an AdpA regulon. ArpA, which belongs to the TetR family, contains a helix–turn–helix DNA-binding motif in its N-terminal portion and an A-factor-binding pocket (5 Å (0.5 nm) diameter and 20 Å (2 nm) long) in its C-terminal portion, as implied by X-ray crystallography of CprB, an ArpA homologue. The ligand pocket, which can accommodate an entire A-factor-type molecule of γ-butyrolactone, is completely embedded in the C-terminal portion. Upon binding A-factor, a long helix connecting the A-factor-binding and ligand-binding domains is relocated, as a result of which the DNA-binding helix moves outside, resulting in dissociation from DNA. AdpA, which belongs to the AraC/XylS family, contains a ThiJ/PfpI/DJ-1-like dimerization domain in its N-terminal portion and an AraC/XylS-type DNA-binding domain in its C-terminal portion. For transcriptional activation, AdpA can bind to various positions with respect to the transcriptional start points of the target genes and sometimes to multiple sites. We show here how A-factor triggers secondary metabolism and morphological development in S. griseus, with emphasis on the two key transcriptional factors, ArpA and AdpA, in the A-factor regulatory cascade.

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