Deletion of the SNP1 trypsin protease from Stagonospora nodorum reveals another major protease expressed during infection

Bindschedler, Laurence V.; Sanchez, Pedro; Dunn, Steven; Mikán, José; Thangavelu, Madan; Clarkson, John M.; Cooper, Richard M.

doi:10.1016/s1087-1845(02)00517-0

Cited by 29 publications

(21 citation statements)

References 51 publications

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“…Prima facie, these enzymes are candidates for analysis of their roles in aggressiveness by site-directed mutagenesis. However, this approach may be difficult because most fungi have multiple depolymerases and can compensate for the loss of any single enzyme with related enzyme(s) or by expressing a previously latent gene(s) (8). Our results strongly suggest that the antagonism of T. harzianum to A. bisporus is not primarily the result of mycoparasitism.…”

Section: Discussionmentioning

confidence: 75%

“…To 50-l test samples, 100 l of azocasein substrate (both preincubated at 37°C) was added, and the reaction mixtures were incubated for 180 min at 37°C (9). Chymoelastase-like and trypsin-like protease activities were measured against the nitroanilide substrates (Sigma) suc-(Ala) 2 -Pro-Phe-pNA and benzoyl-PheVal-Arg-pNA, respectively (8,47,48). Reaction mixtures at 25°C contained 40 l of test sample, 160 l of Tris-HCl buffered to pH 8.0 (0.1 M), and 50 l of substrate (2 mM) in dimethyl sulfoxide.…”

Section: Methodsmentioning

confidence: 99%

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Saprotrophic and Mycoparasitic Components of Aggressiveness of Trichoderma harzianum Groups toward the Commercial Mushroom Agaricus bisporus

Williams

Clarkson

Mills³

et al. 2003

Appl Environ Microbiol

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We examined the mycoparasitic and saprotrophic behavior of isolates representing groups of Trichoderma harzianum to establish a mechanism for the aggressiveness towards Agaricus bisporus in infested commercial compost. Mycoparasitic structures were infrequently observed in interaction zones on various media, including compost, with cryoscanning electron microscopy. T. harzianum grows prolifically in compost in the absence or presence of A. bisporus, and the aggressive European (Th2) and North American (Th4) isolates produced significantly higher biomasses (6.8-and 7.5-fold, respectively) in compost than did nonaggressive, group 1 isolates. All groups secreted depolymerases that could attack the cell walls of A. bisporus and of wheat straw, and some were linked to aggressiveness. Growth on mushroom cell walls in vitro resulted in rapid production of chymoelastase and trypsin-like proteases by only the Th2 and Th4 isolates. These isolates also produced a dominant protease isoform (pI 6.22) and additional chitinase isoforms. On wheat straw, Th4 produced distinct isoforms of cellulase and laminarinase, but there was no consistent association between levels or isoforms of depolymerases and aggressiveness. Th3's distinctive profiles confirmed its reclassification as Trichoderma atroviride. Proteases and glycanases were detected for the first time in sterilized compost colonized by T. harzianum. Xylanase dominated, and some isoforms were unique to compost, as were some laminarinases. We hypothesize that aggressiveness results from competition, antagonism, or parasitism but only as a component of, or following, extensive saprotrophic growth involving degradation of wheat straw cell walls.

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Section: Discussionmentioning

confidence: 75%

Section: Methodsmentioning

confidence: 99%

Saprotrophic and Mycoparasitic Components of Aggressiveness of Trichoderma harzianum Groups toward the Commercial Mushroom Agaricus bisporus

Williams

Clarkson

Mills³

et al. 2003

Appl Environ Microbiol

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“…The secretion of proteases (Bindschedler et al, 2003), xylanases, and cellulases suggests that the fungus catabolizes plant proteins and carbohydrates for energy in planta at this late stage of infection. Studies in a range of pathogens suggest that early infection is characterized by the catabolism of internal lipid stores and that mid stages are characterized by the use of external sugars and amino acids (Solomon et al, 2003a).…”

Section: Gene Expression During Infectionmentioning

confidence: 99%

“…nodorum is an experimentally tractable organism, which is easily handled in defined media, was one of the first fungal pathogens to be genetically manipulated (Cooley et al, 1988), and has been a model for fungicide development (Dancer et al, 1999). Molecular analysis of pathogenicity determinants is aided by facile tools for gene ablation and rapid in vitro phenotypic screens, and thus far, a small number of genes required for pathogenicity have been identified (Cooley et al, 1988;Bailey et al, 1996;Bindschedler et al, 2003;Solomon et al, 2003bSolomon et al, , 2004aSolomon et al, , 2004bSolomon et al, , 2005Solomon et al, , 2006a. It has thus emerged as a model for dothideomycete pathology.…”

Section: Introductionmentioning

confidence: 99%

Dothideomycete–Plant Interactions Illuminated by Genome Sequencing and EST Analysis of the Wheat Pathogen Stagonospora nodorum

et al. 2007

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Stagonospora nodorum is a major necrotrophic fungal pathogen of wheat (Triticum aestivum) and a member of the Dothideomycetes, a large fungal taxon that includes many important plant pathogens affecting all major crop plant families. Here, we report the acquisition and initial analysis of a draft genome sequence for this fungus. The assembly comprises 37,164,227 bp of nuclear DNA contained in 107 scaffolds. The circular mitochondrial genome comprises 49,761 bp encoding 46 genes, including four that are intron encoded. The nuclear genome assembly contains 26 classes of repetitive DNA, comprising 4.5% of the genome. Some of the repeats show evidence of repeat-induced point mutations consistent with a frequent sexual cycle. ESTs and gene prediction models support a minimum of 10,762 nuclear genes. Extensive orthology was found between the polyketide synthase family in S. nodorum and Cochliobolus heterostrophus, suggesting an ancient origin and conserved functions for these genes. A striking feature of the gene catalog was the large number of genes predicted to encode secreted proteins; the majority has no meaningful similarity to any other known genes. It is likely that genes for host-specific toxins, in addition to ToxA, will be found among this group. ESTs obtained from axenic mycelium grown on oleate (chosen to mimic early infection) and late-stage lesions sporulating on wheat leaves were obtained. Statistical analysis shows that transcripts encoding proteins involved in protein synthesis and in the production of extracellular proteases, cellulases, and xylanases predominate in the infection library. This suggests that the fungus is dependant on the degradation of wheat macromolecular constituents to provide the carbon skeletons and energy for the synthesis of proteins and other components destined for the developing pycnidiospores.

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“…It has been reported that pectinases and cutinase secreted by A. flavus during cotton boll and corn infection are related to Aspergillus virulence (Brown et al 1992;Guo et al 1996, Mellon et al 2007. Proteases are other enzymes identified in a number of plant pathogenic fungi and may play a critical role in successful host colonisation (Di Pietro et al 2001;Pekkarinen and Jones 2002;Bindschedler et al 2003). Physiological studies have suggested that proteases could have a direct effect on the proteins of a plant's plasma membrane or cell wall (Movahedi and Heale 1990;Carlile et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Analysis of protease activity in Aspergillus flavus and A. parasiticus on peanut seed infection and aflatoxin contamination

et al. 2009

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Aspergillus flavus and A. parasiticus are aflatoxin-producing fungi that can infect peanut seeds in field crops. An association between A. parasiticus proteolytic enzyme activities and peanut fungal infection was examined. For this study, a model of inductive and non-inductive culture media to produce A. parasiticus extracellular protease before infection was used. These A. parasiticus cultures were used to infect peanut seeds of cultivars resistant and susceptible to aflatoxin contamination. Peanut seeds of both cultivars exposed to fungi grown on casein medium (inductive medium) showed higher internal and external infection and a higher fungal protease content than those observed on potato dextrose agar (PDA) and sucrose medium (non-inductive media). A further study showed higher fungal colonisation and aflatoxin contamination in seeds of the resistant cultivar preincubated with Aspergillus extracellular proteases than in those incubated without proteases. Moreover, protease activities affected the viability of noninfected resistant cultivar seeds, inhibiting germination and radicle elongation and enhancing seed tissue injury. The results strongly suggest that protease production by A. parasiticus is involved in peanut seed infection and aflatoxin contamination resulting in seed tissue damage, affecting seed viability and facilitating the access of fungi through the testa. The analysis of fungal extracellular proteases formed on peanut seed during infection showed that A. flavus and A. parasiticus produced metallo and serine proteases; however, there were differences in the molecular masses of the enzymes between both species. The greatest activity in both species was by serine protease, that could be classified as subtilase.

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Deletion of the SNP1 trypsin protease from Stagonospora nodorum reveals another major protease expressed during infection

Cited by 29 publications

References 51 publications

Saprotrophic and Mycoparasitic Components of Aggressiveness of Trichoderma harzianum Groups toward the Commercial Mushroom Agaricus bisporus

Saprotrophic and Mycoparasitic Components of Aggressiveness of Trichoderma harzianum Groups toward the Commercial Mushroom Agaricus bisporus

Dothideomycete–Plant Interactions Illuminated by Genome Sequencing and EST Analysis of the Wheat Pathogen Stagonospora nodorum

Analysis of protease activity in Aspergillus flavus and A. parasiticus on peanut seed infection and aflatoxin contamination

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