Regulation of melanin biosynthesis via the dihydroxynaphthalene pathway is dependent on sexual development in the ascomycete<i>Sordaria macrospora</i>

Engh, Ines; Nowrousian, Minou; Kück, Ulrich

doi:10.1111/j.1574-6968.2007.00867.x

Cited by 69 publications

(60 citation statements)

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“…First, we analyzed the expression levels of four different genes involved in melanin biosynthesis: a polyketide synthase gene (pks), a scytalone dehydratase gene (sdh), a tetrahydroxynaphthalene reductase gene (teh), and a trihydroxynaphthalene reductase gene (tih) (22). In comparison to the WT, none of these genes was differentially regulated in ⌬SmtA-1 whereas sdh, the, and tih are significantly downregulated in ⌬SmtA-2 (see Fig.…”

Section: Resultsmentioning

confidence: 99%

Functional Characterization of MAT1 - 1 -Specific Mating-Type Genes in the Homothallic Ascomycete Sordaria macrospora Provides New Insights into Essential and Nonessential Sexual Regulators

Klix¹,

et al. 2010

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Mating-type genes in fungi encode regulators of mating and sexual development. Heterothallic ascomycete species require different sets of mating-type genes to control nonself-recognition and mating of compatible partners of different mating types. Homothallic (self-fertile) species also carry mating-type genes in their genome that are essential for sexual development. To analyze the molecular basis of homothallism and the role of mating-type genes during fruiting-body development, we deleted each of the three genes, SmtA-1 (MAT1-1-1), SmtA-2 (MAT1-1-2), and SmtA-3 (MAT1-1-3), contained in the MAT1-1 part of the mating-type locus of the homothallic ascomycete species Sordaria macrospora. Phenotypic analysis of deletion mutants revealed that the PPF domain protein-encoding gene SmtA-2 is essential for sexual reproduction, whereas the ␣ domain protein-encoding genes SmtA-1 and SmtA-3 play no role in fruiting-body development. By means of crossspecies microarray analysis using Neurospora crassa oligonucleotide microarrays hybridized with S. macrospora targets and quantitative real-time PCR, we identified genes expressed under the control of SmtA-1 and SmtA-2. Both genes are involved in the regulation of gene expression, including that of pheromone genes.Sex, one mechanism of the genetic diversity of species, is ubiquitous across kingdoms. To avoid self-crossing, genetic barriers have evolved that prevent selfing, and these often culminate in sexual dimorphism. In filamentous ascomycetes, sexual dimorphism is almost nonexistent, and in many cases individuals are hermaphrodites. Here, sex is determined genetically by a sex-specific region in the genome known as the mating-type locus (MAT) (10).Fungi exhibit two different sexual life styles, homothallism (self-fertility) and heterothallism (self-sterility) (46). This phenomenon was first discovered by Blakeslee in the group of zygomycetes, a lineage that diverged early within the fungal kingdom (5). Only recently was the sequence of the matingtype locus of Phycomyces blakesleeanus (Zygomycota) discovered (36). It was shown that each mating-type locus contains one single gene coding for a protein with a high-mobility group (HMG) (31) (Fig. 1). Both genes show low-level amino acid similarity and confer the ability to mate as either a MAT (Ϫ) or a MAT (ϩ) strain.Similarly, heterothallic ascomycetes contain a single matingtype locus with two alternate alleles. The DNA sequences at the mating-type locus in individuals of different mating types show almost no homology. To emphasize the dissimilarity between and the different origins of the genes of different matingtype loci, they have been termed idiomorphs instead of alleles (49).In ascomycetes, mating is best characterized at the molecular level in the budding yeast Saccharomyces cerevisiae. The MAT idiomorphs, MATa and MAT␣, encode regulatory proteins which, in combination with other transcription factors, are responsible for a distinct pattern of expression in the three yeast cell types: haploid MATa and MAT␣ cells and d...

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Section: Resultsmentioning

confidence: 99%

Functional Characterization of MAT1 - 1 -Specific Mating-Type Genes in the Homothallic Ascomycete Sordaria macrospora Provides New Insights into Essential and Nonessential Sexual Regulators

Klix¹,

et al. 2010

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“…The 1,8-dihydroxynaphthalene melanin pathway found in Wangiella dermatitidis, Sordaria macrospora, Colletotrichum lagenarium, Magnaporthe grisea, Neurospora crassa, Alternaria alternata, and several Aspergillus species is currently the best described fungal mycelium pigment biosynthetic pathway (34,35). The pathway includes two dehydration reactions catalyzed by scytalone dehydratase (SD) (EC 4.2.1.94) (Fig.…”

Section: Discussionmentioning

confidence: 99%

Two Novel Classes of Enzymes Are Required for the Biosynthesis of Aurofusarin in Fusarium graminearum

Frandsen

Schütt

Lund

et al. 2011

Journal of Biological Chemistry

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Previous studies have reported the functional characterization of 9 out of 11 genes found in the gene cluster responsible for biosynthesis of the polyketide pigment aurofusarin in Fusarium graminearum. Here we reanalyze the function of a putative aurofusarin pump (AurT) and the two remaining orphan genes, aurZ and aurS. Targeted gene replacement of aurZ resulted in the discovery that the compound YWA1, rather than nor-rubrofusarin, is the primary product of F. graminearum polyketide synthase 12 (FgPKS12). AurZ is the first representative of a novel class of dehydratases that act on hydroxylated ␥-pyrones. Replacement of the aurS gene resulted in accumulation of rubrofusarin, an intermediate that also accumulates when the GIP1, aurF, or aurO genes in the aurofusarin cluster are deleted. Based on the shared phenotype and predicted subcellular localization, we propose that AurS is a member of an extracellular enzyme complex (GIP1-AurF-AurO-AurS) responsible for converting rubrofusarin into aurofusarin. This implies that rubrofusarin, rather than aurofusarin, is pumped across the plasma membrane. Replacement of the putative aurofusarin pump aurT increased the rubrofusarin-to-aurofusarin ratio, supporting that rubrofusarin is normally pumped across the plasma membrane. These results provide functional information on two novel classes of proteins and their contribution to polyketide pigment biosynthesis.The plant pathogenic fungus Fusarium graminearum (teleomorph Gibberella zeae) is capable of producing a plethora of secondary metabolites, many of which belong to the polyketide class of compounds, such as the mycotoxins zearalenone, fusarin C, and aurofusarin (1). The F. graminearum genome encodes 15 polyketide synthases (PKS) 2 (2, 3), of which FgPKS12 is the progenitor of nor-rubrofusarin/rubrofusarin/aurofusarin (4, 5), FgPKS4 and FgPKS13 are the progenitors of zearalenone (1, 6), FgPKS10 is the progenitor of fusarin C (7, 8), and FgPKS3 is the progenitor of an uncharacterized black/purple perithecial pigment (8). PKS genes are typically found in gene clusters that comprise genes encoding transcription factor, transporters, and tailoring enzymes required for biosynthesis of the final product (1, 4 -6). In addition to genes encoding well characterized classes of enzymes, the clusters typically also include orphan genes that encode proteins annotated as "hypothetical" or "conserved hypothetical proteins," signifying that no similarity to any previously characterized protein has been found. In the case of F. graminearum, more than half of all gene models found in the Fusarium graminearum Genome Database from the Munich Information Center for Protein Sequences (MIPS) fall into either of these two categories (9).Functional characterization of hypothetical proteins is challenging, but those belonging to secondary metabolite gene clusters provide a unique opportunity because their location suggests a function in the respective biosynthetic pathways. The PKS12 gene cluster in F. graminearum, which is responsible for biosyn...

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“…According to the rational that mutants could be distinguished by mycelial color change, we chose a polyketide synthase gene (pks-1) as a target to make a knock-down mutant, as it shares similarity to PKSs involved in melanin formation. The molecular genetics of polyketide synthases involved in melanin biosynthesis has been studied in many fungi, including Sordaria macrospora [33], Bipolaris oryzae [34] and Colletotrichum lagenarium [35]. The C. globosum pks-1 gene encodes a PKS that shares highest similarity to the melanin PKS from Neurospora tetrasperma (EGO61342.1, with 65% identity).…”

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confidence: 99%

A PKS gene, pks-1, is involved in chaetoglobosin biosynthesis, pigmentation and sporulation in Chaetomium globosum

Hao

Lou

et al. 2012

Sci. China Life Sci.

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Chaetomium globosum is one of the most common fungi in nature. It is best known for producing chaetoglobosins; however, the molecular basis of chaetoglobosin biosynthesis is poorly understood in this fungus. In this study, we utilized RNA interference (RNAi) to characterize a polyketide synthase gene, pks-1, in C. globosum that is involved in the production of chaetoglobosin A. When pks-1 was knocked down by RNAi, the production of chaetoglobosin A dramatically decreased. Knock-down mutants also displayed a pigment-deficient phenotype. These results suggest that the two polyketides, melanin and chaetoglobosin, are likely to share common biosynthetic steps. Most importantly, we found that pks-1 also plays a critical role in sporulation. The silenced mutants of pks-1 lost the ability to produce spores. We propose that polyketides may modulate cellular development via an unidentified action. We also suggest that C. globosum pks-1 is unique because of its triple role in melanin formation, chaetoglobosin biosynthesis and sporulation. This work may shed light on chaetoglobosin biosynthesis and indicates a relationship between secondary metabolism and fungal morphogenesis.

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Regulation of melanin biosynthesis via the dihydroxynaphthalene pathway is dependent on sexual development in the ascomyceteSordaria macrospora

Cited by 69 publications

References 55 publications

Functional Characterization of MAT1 - 1 -Specific Mating-Type Genes in the Homothallic Ascomycete Sordaria macrospora Provides New Insights into Essential and Nonessential Sexual Regulators

Functional Characterization of MAT1 - 1 -Specific Mating-Type Genes in the Homothallic Ascomycete Sordaria macrospora Provides New Insights into Essential and Nonessential Sexual Regulators

Two Novel Classes of Enzymes Are Required for the Biosynthesis of Aurofusarin in Fusarium graminearum

A PKS gene, pks-1, is involved in chaetoglobosin biosynthesis, pigmentation and sporulation in Chaetomium globosum

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