Production of Cell Wall-Degrading Enzymes by Aspergillus nidulans: A Model System for Fungal Pathogenesis of Plants

Dean, Ralph A.; Timberlake, William E.

doi:10.2307/3869006

Cited by 22 publications

(19 citation statements)

References 11 publications

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“…Previous work has shown that the production of extracellular polygalacturonases by Aspergillus niger (30), A. nidulans (31), and Penicillium frequentans (32) is induced by the presence of pectin and repressed by glucose. In addition, the carbon catab- olite repression of the polygalacturonase expression by glucose has been reported to operate at the transcriptional level (30,33,34).…”

Section: Discussionmentioning

confidence: 99%

Molecular Cloning and Characterization of a Rhamnogalacturonan Acetylesterase from Aspergillus aculeatus

Kauppinen

Stephan

Kofod

et al. 1995

Journal of Biological Chemistry

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A rhamnogalacturonan acetylesterase (RGAE) was purified to homogeneity from the filamentous fungus Aspergillus aculeatus, and the NH 2 -terminal amino acid sequence was determined. Full-length cDNAs encoding the enzyme were isolated from an A. aculeatus cDNA library using a polymerase chain reaction-generated product as a probe. The 936-base pair rha1 cDNA encodes a 250-residue precursor protein of 26,350 Da, including a 17-amino acid signal peptide. The rha1 cDNA was overexpressed in Aspergillus oryzae, a filamentous fungus that does not possess RGAE activity, and the recombinant enzyme was purified and characterized. Mass spectrometry of the native and recombinant RGAE revealed that the enzymes are heterogeneously glycosylated. In addition, the observed differences in their molecular masses, lectin binding patterns, and monosaccharide compositions indicate that the glycan moieties on the two enzymes are structurally different. The RGAE was shown to act in synergy with rhamnogalacturonase A as well as rhamnogalacturonase B from A. aculeatus in the degradation of apple pectin rhamnogalacturonan. RNA gel blot analyses indicate that the expression of rhamnogalacturonan degrading enzymes by A. aculeatus is regulated at the level of transcription and is subjected to carbon catabolite repression by glucose.Pectic polysaccharides are located predominantly in the middle lamella and primary cell wall of dicotyledonous plants (1). The main backbone in pectins can be divided into linear homogalacturonan (smooth) regions of up to 200 residues of (1,4)-linked ␣-D-galacturonic acid (GalUA) 1 and highly branched rhamnogalacturonan (hairy) regions consisting of repeatingIn general, about half of the Rha residues in the hairy regions are substituted with neutral oligosaccharides such as arabinans, galactans, and arabinogalactans. Most pectic substances are furthermore esterified with acetyl or methyl groups at some of the GalUA residues in the backbone (1, 4).Many saprophytic and plant pathogenic fungi and bacteria possess an array of extracellular enzymes involved in the degradation of plant cell wall polymers (5, 6). In the primary cell wall, the cellulose-xyloglucan framework is embedded in a matrix of pectic polysaccharides, which thereby control the access of hydrolytic enzymes to the cellulose and hemicellulose substrates (1, 7). Thus, pectinases are often the first cell wall degrading enzymes produced by plant pathogens when cultured on purified plant cell walls or during infection (8, 9). Due to the structural complexity of the pectin matrix a synergistic or sequential action of several different pectinolytic enzymes is required for efficient breakdown (5). For example, the hydrolysis of smooth regions of pectin by polygalacturonases is highly dependent upon demethylation of the homogalacturonan backbone by pectin methylesterase (5). Similarly, the degradation of rhamnogalacturonan by rhamnogalacturonases (RGases) depends on the removal of the acetyl esters from the substrate (10, 11). Thus, the presence of a rhamnogala...

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Section: Discussionmentioning

confidence: 99%

Molecular Cloning and Characterization of a Rhamnogalacturonan Acetylesterase from Aspergillus aculeatus

Kauppinen

Stephan

Kofod

et al. 1995

Journal of Biological Chemistry

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“…Dean and Timberlake () proposed a threshold level of NO is required to switch from asexual development to sexual development in A. nidulans (Dean & Timberlake, ). Supplementing the NO‐releasing compound (diethylenetriamine NONOate: (Z)‐1‐[N‐(2‐aminoethyl)‐N‐(2‐ammonioethyl) amino] diazen‐1‐ium‐1,2‐diolate) reduced conidiation but stimulated the formation of sexual structure cleistothecia in Aspergillus species (Baidya et al, ; Marcos et al, ).…”

Section: No and Fungal Cellular Developmentmentioning

confidence: 99%

Nitric oxide as a developmental and metabolic signal in filamentous fungi

Zhao

Lim

et al. 2020

Molecular Microbiology

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The short‐lived hydrophobic gas nitric oxide (NO) is a broadly conserved signaling molecule in all domains of life, including the ubiquitous and versatile filamentous fungi (molds). Several studies have suggested that NO plays a vast and diverse signaling role in molds. In this review, we summarize NO‐mediated signaling and the biosynthesis and degradation of NO in molds, and highlight the recent advances in understanding the NO‐mediated regulation of morphological and physiological processes throughout the fungal life cycle. In particular, we describe the role of NO in molds as a signaling molecule that modulates asexual and sexual development, the formation of infection body appressorium, and the production of secondary metabolites (SMs). In addition, we also summarize NO detoxification and protective mechanisms against nitrooxidative stress.

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“…Its estimated 31-megabase genome (1) with low repetitive DNA content (2), distributed among eight chromosomes, is sufficiently complex to direct multicellular development (3,4). With its sophisticated forward and reverse genetics (5,6), A. nidulans has been used to address fundamental questions in cell and molecular biology (7)(8)(9)(10) and has become a model system for the study of pathogenic and biotechnologically useful relatives (11,12). One of the major questions in genomics is the organization of repeated DNA sequences in a genome because this organization has implications for functional organization of genomes, development, chromosome structure and function, recombination, and genome evolution.…”

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confidence: 99%

In vitro reconstruction of the Aspergillus (= Emericella ) nidulans genome

Prade

Griffith²,

Kochut³

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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A physical map of the 31-megabase Aspergillus nidulans genome is reported, in which 94% of 5,134 cosmids are assigned to 49 contiguous segments. The physical map is the result of a two-way ordering process, in which clones and probes were ordered simultaneously on a binary DNA͞DNA hybridization matrix. Compression by elimination of redundant clones resulted in a minimal map, which is a chromosome walk. Repetitive DNA is nonrandomly dispersed in the A. nidulans genome, reminiscent of heterochromatic banding patterns of higher eukaryotes. We hypothesize gene clusters may arise by horizontal transfer and spread by transposition to explain the nonrandom pattern of repeats along chromosomes.The ascomycetous fungus Aspergillus nidulans is one of the simplest multicellular eukaryotes. Its estimated 31-megabase genome (1) with low repetitive DNA content (2), distributed among eight chromosomes, is sufficiently complex to direct multicellular development (3, 4). With its sophisticated forward and reverse genetics (5, 6), A. nidulans has been used to address fundamental questions in cell and molecular biology (7-10) and has become a model system for the study of pathogenic and biotechnologically useful relatives (11, 12). One of the major questions in genomics is the organization of repeated DNA sequences in a genome because this organization has implications for functional organization of genomes, development, chromosome structure and function, recombination, and genome evolution. Small eukaryotic genomes provide excellent models for the development of novel mapping technologies for larger genomes. For example, the A. nidulans genome is entirely covered (tiled) by 775 nonoverlapping cosmids (averaging Ϸ40-kb inserts) and the human genome, with 3,000 yeast artificial chromosomes [averaging Ϸ1,001-kb inserts, (13)]. Here we present a physical mapping strategy that produces a portrait of how repeated DNA sequences are distributed in small eukaryotic genomes. MATERIALS AND METHODSLibraries. Two independent libraries were constructed in the Lambda-based cosmid vector pLORIST2 and the pBRbased cosmid vector pWE15 (1).Physical Mapping Strategy. For the physical mapping experiment, pulsed field gel electrophoresis isolated chromosomes were radiolabeled and used, one by one, to probe the two genomic libraries (5,134 clones stamped onto seven highdensity gridded 5 ϫ 3.5-inch nylon membranes containing 864 clones each) to show the chromosomal affiliations of each clone (1). With this information, clones were sorted into subsets (S for specific to one chromosome, R for repeated hybridization to several, but not all, chromosomes, and O for octochromosomal). Octochromosomal (O) clones hybridized to all eight A. nidulans chromosomes. The numbers of S, R, and O clones in the genomic library were 3,307 (64.4%), 1,769 (34.4%), and 58 (1.1%), respectively. Then, only S clones were radiolabeled and used to probe the genomic library of 5,134 clones (on seven identical membranes)

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Production of Cell Wall-Degrading Enzymes by Aspergillus nidulans: A Model System for Fungal Pathogenesis of Plants

Cited by 22 publications

References 11 publications

Molecular Cloning and Characterization of a Rhamnogalacturonan Acetylesterase from Aspergillus aculeatus

Molecular Cloning and Characterization of a Rhamnogalacturonan Acetylesterase from Aspergillus aculeatus

Nitric oxide as a developmental and metabolic signal in filamentous fungi

In vitro reconstruction of the Aspergillus (= Emericella ) nidulans genome

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