A Homologue of the
            <i>Aspergillus velvet</i>
            Gene Regulates both Cephalosporin C Biosynthesis and Hyphal Fragmentation in
            <i>Acremonium chrysogenum</i>

Dreyer, Jacqueline; Eichhorn, Heiko; Friedlin, Ernst; Kürnsteiner, Hubert; Kück, Ulrich

doi:10.1128/aem.00129-07

Cited by 126 publications

(121 citation statements)

References 49 publications

(60 reference statements)

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“…D00909.1, Table 2). This resulted in the isolation of cosmid H2, carrying the 39 end of the coding region of sac1 that was further sequenced by primer walking and random insertion of pGPS2.1-hph plasmid (Dreyer et al 2007) using the Tn7L and Tn7R sequences of the integrated transposable element. The 59 end of the sac1 gene and its 59 flanking region was amplified from genomic S. macrospora DNA with an oligonucleotide (u-cr-1) homologous to the corresponding N. crassa sequence and a S. macrospora-specific oligonucleotide (sac10s).…”

Section: Methodsmentioning

confidence: 99%

Three α-Subunits of Heterotrimeric G Proteins and an Adenylyl Cyclase Have Distinct Roles in Fruiting Body Development in the Homothallic Fungus Sordaria macrospora

et al. 2008

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Sordaria macrospora, a self-fertile filamentous ascomycete, carries genes encoding three different a-subunits of heterotrimeric G proteins (gsa, G protein Sordaria alpha subunit). We generated knockout strains for all three gsa genes (Dgsa1, Dgsa2, and Dgsa3) as well as all combinations of double mutants. Phenotypic analysis of single and double mutants showed that the genes for Ga-subunits have distinct roles in the sexual life cycle. While single mutants show some reduction of fertility, double mutants Dgsa1Dgsa2 and Dgsa1Dgsa3 are completely sterile. To test whether the pheromone receptors PRE1 and PRE2 mediate signaling via distinct Ga-subunits, two recently generated Dpre strains were crossed with all Dgsa strains. Analyses of the corresponding double mutants revealed that compared to GSA2, GSA1 is a more predominant regulator of a signal transduction cascade downstream of the pheromone receptors and that GSA3 is involved in another signaling pathway that also contributes to fruiting body development and fertility. We further isolated the gene encoding adenylyl cyclase (AC) (sac1) for construction of a knockout strain. Analyses of the three DgsaDsac1 double mutants and one Dgsa2Dgsa3Dsac1 triple mutant indicate that SAC1 acts downstream of GSA3, parallel to a GSA1-GSA2-mediated signaling pathway. In addition, the function of STE12 and PRO41, two presumptive signaling components, was investigated in diverse double mutants lacking those developmental genes in combination with the gsa genes. This analysis was further completed by expression studies of the ste12 and pro41 transcripts in wild-type and mutant strains. From the sum of all our data, we propose a model for how different Ga-subunits interact with pheromone receptors, adenylyl cyclase, and STE12 and thus cooperatively regulate sexual development in S. macrospora.

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Section: Methodsmentioning

confidence: 99%

Three α-Subunits of Heterotrimeric G Proteins and an Adenylyl Cyclase Have Distinct Roles in Fruiting Body Development in the Homothallic Fungus Sordaria macrospora

et al. 2008

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“…These reverse genetic studies analyzed well-known regulators of conidiogenesis, such as the fluffy genes, which are activators of the central development pathway genes brlA, abaA, and wetA (2,4,(13)(14)(15)(16). The sensory and regulatory functions of velvet complexes have been well described (4,17,18), and their orthologs have been characterized in many fungi (19)(20)(21)(22)(23)(24)(25)(26)(27).…”

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WetA Is Required for Conidiogenesis and Conidium Maturation in the Ascomycete Fungus Fusarium graminearum

et al. 2014

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c Fusarium graminearum, a prominent fungal pathogen that infects major cereal crops, primarily utilizes asexual spores to spread disease. To understand the molecular mechanisms underlying conidiogenesis in F. graminearum, we functionally characterized the F. graminearum ortholog of Aspergillus nidulans wetA, which has been shown to be involved in conidiogenesis and conidium maturation. Deletion of F. graminearum wetA did not alter mycelial growth, sexual development, or virulence, but the wetA deletion mutants produced longer conidia with fewer septa, and the conidia were sensitive to acute stresses, such as oxidative stress and heat stress. Furthermore, the survival rate of aged conidia from the F. graminearum wetA deletion mutants was reduced. The wetA deletion resulted in vigorous generation of single-celled conidia through autophagy-dependent microcycle conidiation, indicating that WetA functions to maintain conidial dormancy by suppressing microcycle conidiation in F. graminearum. Transcriptome analyses demonstrated that most of the putative conidiation-related genes are expressed constitutively and that only a few genes are specifically involved in F. graminearum conidiogenesis. The conserved and distinct roles identified for WetA in F. graminearum provide new insights into the genetics of conidiation in filamentous fungi.

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“…VeA is a light-dependent regulator governing both development and SM production in several aspergilli (A. flavus, A. parasiticus, and A. nidulans) (12,14,16,26) as well as in other genera, including Fusarium (30,31,43), Neurospora (2), and Acremonium (15). VeA is also involved in activation of sexual development and inhibition of asexual development (reviewed in references 11 and 28).…”

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Suppressor Mutagenesis Identifies a Velvet Complex Remediator of Aspergillus nidulans Secondary Metabolism

et al. 2010

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Fungal secondary metabolites (SM) are bioactive compounds that are important in fungal ecology and, moreover, both harmful and useful in human endeavors (e.g., as toxins and pharmaceuticals). Recently a nuclear heterocomplex termed the Velvet complex, characterized in the model ascomycete Aspergillus nidulans, was found to be critical for SM production. Deletion of two members of the Velvet complex, laeA and veA, results in near loss of SM and defective sexual spore production in A. nidulans and other species. Using a multicopy-suppressor genetics approach, we have isolated an Aspergillus nidulans gene named rsmA (remediation of secondary metabolism) based upon its ability to remediate secondary metabolism in ⌬laeA and ⌬veA backgrounds. Overexpression of rsmA (OE::rsmA) restores production of sterigmatocystin (ST) (a carcinogenic SM) via transcriptional activation of ST biosynthetic genes. However, defects in sexual reproduction in either ⌬laeA or ⌬veA strains cannot be overcome by OE::rsmA. An intact Velvet complex coupled with an OE::rsmA allele increases SM many fold over the wild-type level, but loss of rsmA does not decrease SM. RsmA encodes a putative bZIP basic leucine zipper-type transcription factor.Secondary metabolites are biologically active compounds that are diverse in structure and often possess either pharmacological or toxic properties. To customize and control the biosynthesis of these natural products, we must understand how secondary metabolites (SM) are regulated. In fungi, SM production is controlled by global transcription factors encoded by genes unlinked to the SM biosynthetic gene clusters. Such genes regulate multiple physiological processes and generally respond to environmental cues such as pH, temperature, and nutrition (27,45). Regulation of many clustered genes is also largely dependent on pathway-specific transcription (18,22,42) and signal transduction pathways that link secondary metabolism with sporulation (13).LaeA is a global regulator of SM in the aspergilli. LaeA, a putative methyltransferase, was first identified in Aspergillus nidulans (5), A. fumigatus (6), and, subsequently, A. flavus (25). Overexpression (OE) of laeA increases the production of multiple metabolites in the aspergilli, whereas deletion of laeA silences expression of SM genes (1,5,8,20). LaeA is thus used as a genomic mining tool, providing a novel method for identifying new SM through microarray and chemical analyses (8,20,34). Moreover, deletion of laeA in A. fumigatus decreases the virulence of this human pathogen (4, 6); similarly, A. flavus laeA deletants are also reduced in virulence on host seed (1, 25). LaeA homologs are also found in other filamentous fungi such as Penicillium chrysogenum and Fusarium fujikuroi, where they control SM, pigmentation, sporulation, and virulence (29,43).Another important SM regulatory protein identified in A. nidulans is encoded by veA, otherwise known as velvet. VeA is a light-dependent regulator governing both development and SM production in several aspergilli (A...

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A Homologue of the Aspergillus velvet Gene Regulates both Cephalosporin C Biosynthesis and Hyphal Fragmentation in Acremonium chrysogenum

Cited by 126 publications

References 49 publications

Three α-Subunits of Heterotrimeric G Proteins and an Adenylyl Cyclase Have Distinct Roles in Fruiting Body Development in the Homothallic Fungus Sordaria macrospora

Three α-Subunits of Heterotrimeric G Proteins and an Adenylyl Cyclase Have Distinct Roles in Fruiting Body Development in the Homothallic Fungus Sordaria macrospora

WetA Is Required for Conidiogenesis and Conidium Maturation in the Ascomycete Fungus Fusarium graminearum

Suppressor Mutagenesis Identifies a Velvet Complex Remediator of Aspergillus nidulans Secondary Metabolism

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