Trichoderma protoplast fusion: a tool for improving biocontrol agents

1990 ◽  
Vol 36 (1) ◽  
pp. 6-9 ◽  
Author(s):  
S. Pe'er ◽  
I. Chet
Keyword(s):  
Cell Wall ◽  
Key Words ◽  
Protoplast Fusion ◽  
Trichoderma Harzianum ◽  
Pathogenic Fungus ◽  
Sclerotium Rolfsii ◽  
Pathogenic Fungi ◽  
Damping Off ◽  
Dual Cultures ◽  
Young Thalli

Protoplasts from two auxotrophic mutants of Trichoderma harzianum Rifai (ATCC 32173), obtained from young thalli following cell wall digestion by NovoZym 234, were fused in 33% PEG suspended in 10 mM Tris-HCl and 10 mM CaCl2, pH 7.5. The frequency of fusion between lysine- and arginine-requiring auxotrophs resulting in prototrophic strains was about 5%. These prototrophic strains were classified into parental and nonparental types. Colonies developed from single conidia of the nonparental phenotype exhibited prototrophic parental or recombinant phenotypes. The ability of both prototrophic and parental strains to overgrow the soil-borne pathogenic fungi Rhizoctonia solani, Sclerotium rolfsii, and Pythium aphanidermatum in dual cultures was used to evaluate their antagonistic capability. The antagonistic abilities of the prototrophic strains were found to vary with each pathogenic fungus. The prototrophic strain A2 overgrew all the pathogenic fungi more rapidly than the parental strains. Strain A2 effectively controlled Rhizoctonia damping-off of cotton seedlings, in the greenhouse, when compared with the parental strains. Protoplast fusion appears to be a useful tool for combining desirable traits from parental strains to produce improved biocontrol strains. Key words: Trichoderma harzianum, biocontrol, protoplast fusion.

scholarly journals Sclerotium rolfsii Causes White Rot on Taro in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 1000-1000 ◽  
Author(s):  
J.-H. Kwon ◽  
D.-W. Kang ◽  
J. Kim
Keyword(s):  
New York ◽  
South Korea ◽  
Pathogenic Fungus ◽  
Sclerotium Rolfsii ◽  
Pathogenic Fungi ◽  
White Rot ◽  
Its Sequence ◽  
Academic Press ◽  
Its Sequence Analysis ◽  
Plant Pathogenicity

Taro (Colocasia esculenta L.) is grown throughout the world primarily for its tubers, which become edible after cooking. Taro stems are often used in a traditional soup in South Korea. In September 2012, a suspected white rot of taro occurred in a farmer's fields in Jinju, South Korea. Infected plants gradually withered, a white mycelial mat appeared, and numerous sclerotia developed on the surface of petioles near the soil line. The heavily infected petioles rotted and the entire plant eventually died. The freshly isolated pathogenic fungus was grown on potato dextrose agar (PDA) and examined microscopically. Aerial mycelia usually formed many narrow hyphal strands 4 to 8 μm wide. The white mycelia formed a typical clamp connection structure after 6 days growth at 25°C. The sclerotia were white at first, gradually turned dark brown, and were 1 to 3 mm in diameter. Small globoid sclerotia formed abundantly on PDA after 18 days of growth. Ten 2-month-old potted taro plants were inoculated with S. rolfsii-colonized agar discs directly at the base of each plant and kept at 25°C in a greenhouse to test pathogenicity. Three taro plants were inoculated similarly with uncolonized agar discs as controls. Eight days after inoculation, blight symptoms were observed, and S. rolfsii was reisolated from the artificially inoculated plants. The control taro plants remained healthy. We amplified and sequenced an internal transcribed spacer (ITS) rDNA region of the isolate using the ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) primers to confirm the identity of the fungus (2). The resulting 684-bp sequence was deposited in GenBank (Accession No. KC491876). A comparison with other sequences available in the GenBank database revealed that the ITS sequence shared 100% similarity with Sclerotium rolfsii sequences (HQ420816 and JN017199). Based on the symptoms, mycological characteristics, ITS sequence analysis, and host plant pathogenicity, this fungus was identified as S. rolfsii Saccardo (1). To our knowledge, this is the first report of white rot in taro caused by S. rolfsii in Korea. References: (1) J. E. Mordue. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 410, 1974. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, New York, 1990.

scholarly journals Isolation of Endophytic Fungi from Vitex trifolia L and Antagonism Test against Sclerotium rolfsii and pathogenic bacteria

2021 ◽  
Vol 21 (1) ◽  
pp. 72
Author(s):  
Muhammad Hasan Basri ◽  
Lalu Zulkifli ◽  
Abdul Syukur
Keyword(s):  
Biological Control ◽  
Endophytic Fungi ◽  
Pathogenic Bacteria ◽  
Pathogenic Fungus ◽  
Sclerotium Rolfsii ◽  
Pathogenic Fungi ◽  
Promising Alternative ◽  
Environmental Friendly ◽  
Low Activity

Plant damage by pathogenic fungi is often found in plants, one of which is caused by Sclerotium rolfsii. Biological control strategy offers a promising alternative for managing disease in plants because they are environmental friendly compared to pesticides application. One of the biological control offered is by using endophytic fungi isolated from Vitex trivolia L. The aim of the study was to isolate, to identify macroscopic and microscopic endophytic fungi from Vitex trifolia L and to test their antagonism potency against the pathogenic fungus Sclerotium rolfsii in vitro. The isolation obtained 7 endophytic fungi isolates identified based on their genus characteristics, nsmely Periconia sp, Aspergillussp, Dendrophoma  sp, Geotrichum  sp, Ampulliferina  sp, Chalara  sp, dan Bispora sp and 2 isolates have not been identified. The Antibacterial test of the fungi isolate on the 4 tested bacteria showed that of all the fungi isolate have low activity. The antagonism test using the direct opposition method with the PIRG formula, showed that the 3 isolates had high percentage of growth inhibition, in which ALJ1, BLJ5, and ALJ3 isolate has  85%, 90%, and 100% respectively. This potency could be used as biological agents on the pathogenic fungus Sclerotium rolfsii.

Degradation of plant pathogenic fungi by Trichoderma harzianum

1982 ◽  
Vol 28 (7) ◽  
pp. 719-725 ◽  
Author(s):  
Y. Elad ◽  
I. Chet ◽  
Y. Henis
Keyword(s):  
Trichoderma Harzianum ◽  
Cell Walls ◽  
Sole Carbon Source ◽  
Hydrolytic Enzymes ◽  
Sclerotium Rolfsii ◽  
Pathogenic Fungi ◽  
Plant Pathogenic Fungi ◽  
Soilborne Pathogens ◽  
Glucanase Activity ◽  
Trichoderma Isolates

Trichoderma harzianum excreted β-1, 3-glucanase and chitinase into the medium when grown on laminarin and chitin, respectively, or on cell walls of the pathogen Sclerotium rolfsii, as sole carbon source. Trichoderma harzianum also showed high activity of both enzymes when grown on homogenized S. rolfsii sclerotia. Glucanase activity increased by 67% when the fungus was grown on a mixture of laminarin and glucose (3:1, v/v). Similarly, high lytic activity was detected in wheat bran culture of the fungus and in soil inoculated with this culture. Protease and lipase activity were detected in the medium when the antagonist attacked mycelium of S. rolfsii.Isolates of T. harzianum were found to differ in the levels of hydrolytic enzymes produced when mycelium of S. rolfsii, Rhizoctonia solani, and Pythium aphanidermatum in soil was attacked. This phenomenon was correlated with the ability of each of the Trichoderma isolates to control the respective soilborne pathogens.

scholarly journals Ability of Trichoderma harzianum in the Formulation with Carbon Fiber and Silica Nano Particles to Control Damping Off (Sclerotium rolfsii) on Soybean Plants

2018 ◽  
Vol 1 (2) ◽  
pp. 32-43
Author(s):  
Iman Ilahiyyat ◽  
◽  
Hersanti Hersanti ◽  
Luciana Djaya ◽  
Sri Hartati ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Trichoderma Harzianum ◽  
Sclerotium Rolfsii ◽  
Nano Particles ◽  
Second Phase ◽  
Damping Off ◽  
In Vivo Test ◽  
Soybean Plants

Sclerotium rolfsii is one of the soil-borne pathogens that cause damping-off and stem rot on soybean plants. One effort to control damping-off, which is environmentally friendly, is by using biological agents. Antagonistic microorganism that has been studied intensively and has a great potential to control soil-borne diseases is Trichoderma harzianum. The objectives of this research were to comprehend the ability of T. harzianum in a formulation with carbon fiber 80 mesh and silica nanoparticles (NPs.) and to determine the concentration of silica NPs. in the formulation that suppresses the in vitro growth of S. rolfsii and control the damping-off on soybean plants. The experiment was conducted in two phases. The first phase was in vitro experiment, arranged in a completely randomized design with 11 treatments and 3 replications. The second phase was in vivo test by using randomized complete block design, with 11 treatments and 3 replications. The in-vitro test showed that each treatment with T. harzianum in the formulation of silica NPs. and carbon fiber 80 mesh in various concentrations was able to suppress the S. rolfsii growth by 58.76- 80.92%. The treatment of single T. harzianum caused the highest suppression on S. rolfsii up to 80.92%. While the results of the in vivo test showed that the highest percentage of damping-off suppression was on the treatment of T. harzianum only, with 60% suppression.

scholarly journals Impact of Cellulose-Rich Organic Soil Amendments on Growth Dynamics and Pathogenicity of Rhizoctonia solani

2021 ◽  
Vol 9 (6) ◽  
pp. 1285
Author(s):  
Anna Clocchiatti ◽  
Silja Emilia Hannula ◽  
Muhammad Syamsu Rizaludin ◽  
Maria P. J. Hundscheid ◽  
Paulien J. A. klein klein Gunnewiek ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Severity ◽  
Disease Incidence ◽  
Pathogenic Fungus ◽  
Pathogenic Fungi ◽  
Paper Pulp ◽  
Damping Off ◽  
Cellulolytic Bacteria ◽  
Arable Soils ◽  
Saprotrophic Fungi

Cellulose-rich amendments stimulate saprotrophic fungi in arable soils. This may increase competitive and antagonistic interactions with root-infecting pathogenic fungi, resulting in lower disease incidence. However, cellulose-rich amendments may also stimulate pathogenic fungi with saprotrophic abilities, thereby increasing plant disease severity. The current study explores these scenarios, with a focus on the pathogenic fungus Rhizoctonia solani. Saprotrophic growth of R. solani on cellulose-rich materials was tested in vitro. This confirmed paper pulp as a highly suitable substrate for R. solani, whereas its performance on wood sawdusts varied with tree species. In two pot experiments, the effects of amendment of R. solani-infected soil with cellulose-rich materials on performance of beetroot seedlings were tested. All deciduous sawdusts and paper pulp stimulated soil fungal biomass, but only oak, elder and beech sawdusts reduced damping-off of beetroot. Oak sawdust amendment gave a consistent stimulation of saprotrophic Sordariomycetes fungi and of seedling performance, independently of the time between amendment and sowing. In contrast, paper pulp caused a short-term increase in R. solani abundance, coinciding with increased disease severity for beet seedlings sown immediately after amendment. However, damping-off of beetroot was reduced if plants were sown two or four weeks after paper pulp amendment. Cellulolytic bacteria, including Cytophagaceae, responded to paper pulp during the first two weeks and may have counteracted further spread of R. solani. The results showed that fungus-stimulating, cellulose-rich amendments have potential to be used for suppression of R. solani. However, such amendments require a careful consideration of material choice and application strategy.

scholarly journals Test Antifungal Phatogen Extract Secondary Metabolites Of Endophytic Fungi Raru Plant (Cotylelobium melanoxylon)

2016 ◽  
Vol 1 (2) ◽  
pp. 6
Author(s):  
Uswatun Hasanah ◽  
Riwayati Riwayati ◽  
Idramsa Idramsa
Keyword(s):  
Candida Albicans ◽  
Secondary Metabolites ◽  
Endophytic Fungi ◽  
Fungal Pathogens ◽  
Pathogenic Fungus ◽  
Sclerotium Rolfsii ◽  
Pathogenic Fungi ◽  
Inhibition Zone ◽  
Clear Zone ◽  
Paper Disc

This study aims to determine the ability of extracts  secondary metabolites of endophytic fungi raru plant Siarang (Cotylelobium melanoxylon) in inhibiting the growth of pathogenic fungi. Pathogenic fungi tested were Collectotrichum, Fusarium oxysporum, Candida albicans and Sclerotium rolfsii. Test antifungal pathogens carried out by using the method of Kirby-Bour, ie by measuring the clear zone located around the paper disc which is the zone of growth inhibition of pathogenic fungi. Measurement of inhibition zone is done by using a caliper or ruler. The results showed that the secondary metabolites of endophytic fungi extracts could inhibit the growth of pathogenic fungus Candida albicans is the clear zone of 10.23 mm. Keywords : endophytic fungus, Cotylelobium melanoxylon, extract of secondary metabolites, fungal pathogens, inhibition zone

scholarly journals Isolation and Identification of Ssome Lactobacillus Spp. Bacteria and Evaluation Their Efficacy in The Management of Damping off Disease on Peas

2021 ◽  
Vol 910 (1) ◽  
pp. 012106
Author(s):  
Duha Faisal Ajaj ◽  
Abdullah Abdulkarim Hassan
Keyword(s):  
Pathogenic Fungus ◽  
Pathogenic Fungi ◽  
Dry Weight ◽  
Root Systems ◽  
Damping Off ◽  
Biochemical Tests ◽  
Isolation And Identification ◽  
Local Cultivar ◽  
Lactobacillus Spp ◽  
Significant Superiority

Abstract Twenty-eight isolates of Lactobacillus bacteria were isolated from the rhizosphere of pea plants grown in the fields of five districts in Salah al-Din, which included: Tikrit, Al-Alam, Al-Sharqat, Samarra and Baiji, diagnosed according to phenotypic and biochemical tests. Results showed the effect of L. paralimentarius 1081 on vegetative growth characteristics. Treatment of (bacterial filtrate + Ridomil in the presence of pathogenic fungi) was recording the highest values in dry weight of the vegetative and root systems, was 3.91 and 1.23 g respectively in the local cultivar, compared with the lowest values was 2.60 g and 0.76 g respectively in the Syrian cultivar. All treatments inducing plant resistance compared with healthy plants, and the highest activity of the Peroxidase and Polyphenol oxides in the treatment of (Bacterial filtrate + ridomil in the presence of pathogenic fungi), were 1.08 and 1.33 units/ml in the local cultivar, compared to the Syrian cultivar were 0.015 and 0.013, respectively. Results showed a significant decrease in the severity of infection for all treatments compared to the pathogenic fungus treatment, and the lowest infection severity of the vegetative and root systems was recorded in the treatment of (Bacterial filtrate + ridomil in the presence of pathogenic fungi), which was 14.11 and 12.47% in the local cultivar. There was a significant superiority of all treatments in productivity parameters of pea compared to the treatment of pathogenic fungi only, the highest of those parameters including weight of pods and grains weight/plant were recorded in the treatment (Bacterial filtrate + ridomil in the presence of pathogenic fungi) for the local cultivar was 18.07 g and 14.04 g compared to 10.43 g and 8.20 g in the treatment of the Syrian cultivar with pathogenic fungi only.

scholarly journals The PbMDJ1 Gene Belongs to a Conserved MDJ1/LON Locus in Thermodimorphic Pathogenic Fungi and Encodes a Heat Shock Protein That Localizes to both the Mitochondria and Cell Wall of Paracoccidioides brasiliensis

2006 ◽  
Vol 5 (2) ◽  
pp. 379-390 ◽  
Author(s):  
Wagner L. Batista ◽  
Alisson L. Matsuo ◽  
Luciane Ganiko ◽  
Tânia F. Barros ◽  
Thiago R. Veiga ◽  
...  
Keyword(s):  
Cell Wall ◽  
Heat Shock ◽  
Cell Surface ◽  
Paracoccidioides Brasiliensis ◽  
Pathogenic Fungus ◽  
Fungal Growth ◽  
Pathogenic Fungi ◽  
Yeast Cells ◽  
Shock Proteins

ABSTRACT J-domain (DnaJ) proteins, of the Hsp40 family, are essential cofactors of their cognate Hsp70 chaperones, besides acting as independent chaperones. In the present study, we have demonstrated the presence of Mdj1, a mitochondrial DnaJ member, not only in the mitochondria, where it is apparently sorted, but also in the cell wall of Paracoccidioides brasiliensis, a thermodimorphic pathogenic fungus. The molecule (PbMdj1) was localized to fungal yeast cells using both confocal and electron microscopy and also flow cytometry. The anti-recombinant PbMdj1 antibodies used in the reactions specifically recognized a single 55-kDa mitochondrial and cell wall (alkaline β-mercaptoethanol extract) component, compatible with the predicted size of the protein devoid of its matrix peptide-targeting signal. Labeling was abundant throughout the cell wall and especially in the budding regions; however, anti-PbMdj1 did not affect fungal growth in the concentrations tested in vitro, possibly due to the poor access of the antibodies to their target in growing cells. Labeled mitochondria stood preferentially close to the plasma membrane, and gold particles were detected in the thin space between them, toward the cell surface. We show that Mdj1 and the mitochondrial proteinase Lon homologues are heat shock proteins in P. brasiliensis and that their gene organizations are conserved among thermodimorphic fungi and Aspergillus, where the genes are adjacent and have a common 5′ region. This is the first time a DnaJ member has been observed on the cell surface, where its function is speculative.

scholarly journals Vesicle-associated melanization in Cryptococcus neoformans

Microbiology ◽  
2009 ◽  
Vol 155 (12) ◽  
pp. 3860-3867 ◽  
Author(s):  
Helene C. Eisenman ◽  
Susana Frases ◽  
André M. Nicola ◽  
Marcio L. Rodrigues ◽  
Arturo Casadevall
Keyword(s):  
Cell Wall ◽  
Cryptococcus Neoformans ◽  
Extracellular Vesicles ◽  
Lipid A ◽  
Pathogenic Fungus ◽  
Pathogenic Fungi ◽  
Spherical Particles ◽  
Human Pathogenic Fungus ◽  
Kinetics Of

Recently, several pathogenic fungi were shown to produce extracellular vesicles that contain various components associated with virulence. In the human pathogenic fungus Cryptococcus neoformans, these components included laccase, an enzyme that catalyses melanin synthesis. Spherical melanin granules have been observed in the cell wall of C. neoformans. Given that melanin granules have dimensions that are comparable to those of extracellular vesicles, and that metazoan organisms produce melanin in vesicular structures known as melanosomes, we investigated the role of vesicles in cryptococcal melanization. Extracellular vesicles melanized when incubated with the melanin precursor l-3,4-dihydroxyphenylalanine (l-DOPA). The kinetics of substrate incorporation into cells and vesicles was analysed using radiolabelled l-DOPA. The results indicated that substrate incorporation was different for cells and isolated vesicles. Acid-generated melanin ghosts stained with lipophilic dyes, implying the presence of associated lipid. A model for C. neoformans melanization is proposed that accounts for these observations and provides a mechanism for the assembly of melanin into relatively uniform spherical particles stacked in an orderly arrangement in the cell wall.

scholarly journals MrSkn7 Controls Sporulation, Cell Wall Integrity, Autolysis, and Virulence in Metarhizium robertsii

2015 ◽  
Vol 14 (4) ◽  
pp. 396-405 ◽  
Author(s):  
Yanfang Shang ◽  
Peilin Chen ◽  
Yixiong Chen ◽  
Yuzhen Lu ◽  
Chengshu Wang
Keyword(s):  
Cell Wall ◽  
Target Genes ◽  
Response Regulator ◽  
Pathogenic Fungus ◽  
Functional Divergence ◽  
Pathogenic Fungi ◽  
Wild Type ◽  
Metarhizium Robertsii ◽  
Content Type ◽  
Cell Autolysis

ABSTRACT Two-component signaling pathways generally include sensor histidine kinases and response regulators. We identified an ortholog of the response regulator protein Skn7 in the insect-pathogenic fungus Metarhizium robertsii , which we named MrSkn7. Gene deletion assays and functional characterizations indicated that MrSkn7 functions as a transcription factor. The MrSkn7 null mutant of M. robertsii lost the ability to sporulate and had defects in cell wall biosynthesis but was not sensitive to oxidative and osmotic stresses compared to the wild type. However, the mutant was able to produce spores under salt stress. Insect bioassays using these spores showed that the virulence of the mutant was significantly impaired compared to that of the wild type due to the failures to form the infection structure appressorium and evade host immunity. In particular, deletion of MrSkn7 triggered cell autolysis with typical features such as cell vacuolization, downregulation of repressor genes, and upregulation of autolysis-related genes such as extracellular chitinases and proteases. Promoter binding assays confirmed that MrSkn7 could directly or indirectly control different putative target genes. Taken together, the results of this study help us understand the functional divergence of Skn7 orthologs as well as the mechanisms underlying the development and control of virulence in insect-pathogenic fungi.

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