An Antifungal Exo-α-1,3-Glucanase (AGN13.1) from the Biocontrol Fungus Trichoderma harzianum

ABSTRACT Trichoderma harzianum secretes α-1,3-glucanases when it is grown on polysaccharides, fungal cell walls, or autoclaved mycelium as a carbon source (simulated antagonistic conditions). We have purified and characterized one of these enzymes, named AGN13.1. The enzyme was monomeric and slightly basic. AGN13.1 was an exo-type α-1,3-glucanase and showed lytic and antifungal activity against fungal plant pathogens. Northern and Western analyses indicated that AGN13.1 is induced by conditions that simulated antagonism. We propose that AGN13.1 contributes to the antagonistic response of T. harzianum.

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Screening and Antifungal Activity of a β-Carboline Derivative against Cryptococcus neoformans and C. gattii

International Journal of Microbiology ◽

10.1155/2019/7157845 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Kátia Santana Cruz ◽

Emerson Silva Lima ◽

Marcia de Jesus Amazonas da Silva ◽

Erica Simplício de Souza ◽

Andreia Montoia ◽

...

Keyword(s):

Cell Wall ◽

Candida Albicans ◽

Antifungal Activity ◽

Cryptococcus Neoformans ◽

Active Compound ◽

Cell Walls ◽

Human Fibroblasts ◽

Lead Compound ◽

Fungal Cell ◽

Fungal Cell Walls

Background. Cryptococcosis is a fungal disease of bad prognosis due to its pathogenicity and the toxicity of the drugs used for its treatment. The aim of this study was to investigate the medicinal potential of carbazole and β-carboline alkaloids and derivatives against Cryptococcus neoformans and C. gattii. Methods. MICs were established in accordance with the recommendations of the Clinical and Laboratory Standards Institute for alkaloids and derivatives against C. neoformans and C. gattii genotypes VNI and VGI, respectively. A single active compound was further evaluated against C. neoformans genotypes VNII, VNIII, and VNIV, C. gattii genotypes VGI, VGIII, and VGIV, Candida albicans ATCC 36232, for cytotoxicity against the MRC-5 lineage of human fibroblasts and for effects on fungal cells (cell wall, ergosterol, and leakage of nucleic acids). Results. Screening of 11 compounds revealed 8-nitroharmane as a significant inhibitor (MIC 40 μg/mL) of several C. neoformans and C. gattii genotypes. It was not toxic to fibroblasts (IC50 > 50 µg/mL) nor did it alter fungal cell walls or the concentration of ergosterol in C. albicans or C. neoformans. It increased leakage of substances that absorb at 260 nm. Conclusions. The synthetic β-carboline 8-nitroharmane significantly inhibits pathogenic Cryptococcus species and is interesting as a lead compound towards new therapy for Cryptococcus infections.

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Antifungal Activity of Rye (Secale cereale) Seed Chitinases: the Different Binding Manner of Class I and Class II Chitinases to the Fungal Cell Walls

Bioscience Biotechnology and Biochemistry ◽

10.1271/bbb.66.970 ◽

2002 ◽

Vol 66 (5) ◽

pp. 970-977 ◽

Cited By ~ 41

Author(s):

Toki TAIRA ◽

Takayuki OHNUMA ◽

Takeshi YAMAGAMI ◽

Yoichi ASO ◽

Masatsune ISHIGURO ◽

...

Keyword(s):

Antifungal Activity ◽

Secale Cereale ◽

Cell Walls ◽

Class Ii ◽

Class I ◽

Fungal Cell ◽

Fungal Cell Walls

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Antifungal effect of bean endochitinase on Rhizoctonia solani: ultrastructural changes and cytochemical aspects of chitin breakdown

Canadian Journal of Microbiology ◽

10.1139/m93-045 ◽

1993 ◽

Vol 39 (3) ◽

pp. 318-328 ◽

Cited By ~ 84

Author(s):

Nicole Benhamou ◽

Karen Broglie ◽

Richard Broglie ◽

Ilan Chet

Keyword(s):

Antifungal Activity ◽

Rhizoctonia Solani ◽

Cell Walls ◽

Morphological Changes ◽

Enzyme Treatment ◽

Ultrastructural Changes ◽

Early Event ◽

Ultrastructural Observation ◽

Fungal Cell ◽

Fungal Cell Walls

A chitinase, purified to homogeneity from ethylene-treated bean leaves, was applied to actively growing mycelial cells of Rhizoctonia solani to evaluate a potential antifungal activity. Light microscopic investigations at 30-min intervals following enzyme exposure revealed the induction of morphological changes such as swelling of hyphal tips and hyphal distortions. More precise information concerning fungal cell alteration was obtained by ultrastructural observation and cytochemical detection of chitin distribution in fungal cell walls. Chitin breakdown was found to be an early event preceding wall disruption and cytoplasm leakage. The large amounts of chitin present in the walls of control R. solani cells and the rapid chitin hydrolysis upon chitinase treatment lead us to suggest that this polysaccharide is one of the main components of this fungal cell wall and is readily accessible to chitinase, especially in the apical zone. By 60 min after enzyme treatment, labeled molecules were observed in the vicinity of some fungal cells, suggesting the release of chitin oligosaccharides from fungal cell walls. The antifungal activity of the bean chitinase on cells of R. solani grown in culture is discussed in relation to the potential of genetically modified transgenic plants to resist attack by R. solani through an antimicrobial activity in planta.Key words: gold labeling, wheat germ agglutinin, cytochemistry, Rhizoctonia solani, bean endochitinase.

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Degradation of Fungal Cell Walls by Lytic Enzymes of Trichoderma harzianum

Microbiology ◽

10.1099/00221287-135-3-675 ◽

1989 ◽

Vol 135 (3) ◽

pp. 675-682 ◽

Cited By ~ 15

Author(s):

A. Sivan ◽

I. Chet

Keyword(s):

Trichoderma Harzianum ◽

Cell Walls ◽

Lytic Enzymes ◽

Fungal Cell ◽

Fungal Cell Walls

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Analysis of the β-1,3-Glucanolytic System of the Biocontrol Agent Trichoderma harzianum

Applied and Environmental Microbiology ◽

10.1128/aem.64.4.1442-1446.1998 ◽

1998 ◽

Vol 64 (4) ◽

pp. 1442-1446 ◽

Cited By ~ 62

Author(s):

Soledad Vázquez-Garcidueñas ◽

Carlos A. Leal-Morales ◽

Alfredo Herrera-Estrella

Keyword(s):

Trichoderma Harzianum ◽

Cell Walls ◽

Biocontrol Agent ◽

Glucanase Activity ◽

Fungal Cell ◽

Molecular Weights ◽

Cell Wall Lysis ◽

Host Cell Wall ◽

35 Kda Protein ◽

Fungal Cell Walls

ABSTRACT The biocontrol agent Trichoderma harzianum IMI206040 secretes β-1,3-glucanases in the presence of different glucose polymers and fungal cell walls. The level of β-1,3-glucanase activity secreted was found to be proportional to the amount of glucan present in the inducer. The fungus produces at least seven extracellular β-1,3-glucanases upon induction with laminarin, a soluble β-1,3-glucan. The molecular weights of five of these enzymes fall in the range from 60,000 to 80,000, and their pIs are 5.0 to 6.8. In addition, a 35-kDa protein with a pI of 5.5 and a 39-kDa protein are also secreted. Glucose appears to inhibit the formation of all of the inducible β-1,3-glucanases detected. A 77-kDa glucanase was partially purified from the laminarin culture filtrate. This enzyme is glycosylated and belongs to the exo-β-1,3-glucanase group. The properties of this complex group of enzymes suggest that the enzymes might play different roles in host cell wall lysis during mycoparasitism.

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A Fungus-Inducible Pepper Carboxylesterase Exhibits Antifungal Activity by Decomposing the Outer Layer of Fungal Cell Walls

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-11-17-0266-r ◽

2018 ◽

Vol 31 (5) ◽

pp. 505-515 ◽

Cited By ~ 3

Author(s):

Hyo-Hyoun Seo ◽

Ae Ran Park ◽

Hyun-Hwa Lee ◽

Sangkyu Park ◽

Yun-Jeong Han ◽

...

Keyword(s):

Antifungal Activity ◽

Cell Walls ◽

Fungal Pathogens ◽

Mass Spectrometry Analysis ◽

Gas Chromatography Mass Spectrometry ◽

Protective Effects ◽

Fungal Cell ◽

Spectrometry Analysis ◽

Hydrolysis Of ◽

Fungal Cell Walls

Colletotrichum species are major fungal pathogens that cause devastating anthracnose diseases in many economically important crops. In this study, we observed the hydrolyzing activity of a fungus-inducible pepper carboxylesterase (PepEST) on cell walls of C. gloeosporioides, causing growth retardation of the fungus by blocking appressorium formation. To determine the cellular basis for the growth inhibition, we observed the localization of PepEST on the fungus and found the attachment of the protein on surfaces of conidia and germination tubes. Moreover, we examined the decomposition of cell-wall materials from the fungal surface after reaction with PepEST, which led to the identification of 1,2-dithiane-4,5-diol (DTD) by gas chromatography mass spectrometry analysis. Exogenous DTD treatment did not elicit expression of defense-related genes in the host plant but did trigger the necrosis of C. gloeosporioides. Furthermore, the DTD compound displayed protective effects on pepper fruits and plants against C. gloeosporioides and C. coccodes, respectively. In addition, DTD was also effective in preventing other diseases, such as rice blast, tomato late blight, and wheat leaf rust. Therefore, our results provide evidence that PepEST is involved in hydrolysis of the outmost layer of the fungal cell walls and that DTD has antifungal activity, suggesting an alternative strategy to control agronomically important phytopathogens.

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The carbon source-dependent pattern of antimicrobial activity and gene expression in Pseudomonas donghuensis P482

Scientific Reports ◽

10.1038/s41598-021-90488-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marta Matuszewska ◽

Tomasz Maciąg ◽

Magdalena Rajewska ◽

Aldona Wierzbicka ◽

Sylwia Jafra

Keyword(s):

Gene Expression ◽

Antimicrobial Activity ◽

Carbon Source ◽

Reference Genes ◽

Plant Pathogens ◽

Plant Protection ◽

Carbon Sources ◽

Unknown Compound ◽

Fungal Plant Pathogens ◽

The Impact

AbstractPseudomonas donghuensis P482 is a tomato rhizosphere isolate with the ability to inhibit growth of bacterial and fungal plant pathogens. Herein, we analysed the impact of the carbon source on the antibacterial activity of P482 and expression of the selected genes of three genomic regions in the P482 genome. These regions are involved in the synthesis of pyoverdine, 7-hydroxytropolone (7-HT) and an unknown compound (“cluster 17”) and are responsible for the antimicrobial activity of P482. We showed that the P482 mutants, defective in these regions, show variations and contrasting patterns of growth inhibition of the target pathogen under given nutritional conditions (with glucose or glycerol as a carbon source). We also selected and validated the reference genes for gene expression studies in P. donghuensis P482. Amongst ten candidate genes, we found gyrB, rpoD and mrdA the most stably expressed. Using selected reference genes in RT-qPCR, we assessed the expression of the genes of interest under minimal medium conditions with glucose or glycerol as carbon sources. Glycerol was shown to negatively affect the expression of genes necessary for 7-HT synthesis. The significance of this finding in the light of the role of nutrient (carbon) availability in biological plant protection is discussed.

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