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Journal of Nematology Jun 2000Filtrates from nematode-parasitic fungi have been reported to be toxic to plant-parasitic nematodes. Our objective was to determine the effects of fungal filtrates on...
Filtrates from nematode-parasitic fungi have been reported to be toxic to plant-parasitic nematodes. Our objective was to determine the effects of fungal filtrates on second-stage juveniles and eggs of Heterodera glycines. Eleven fungal species that were isolated from cysts extracted from a soybean field in Florida were tested on J2, and five species were tested on eggs in vitro. Each fungal species was grown in Czapek-Dox broth and malt extract broth. No toxic activity was observed for fungi grown in Czapek-Dox broth. Filtrates from Paecilomyces lilacinus, Stagonospora heteroderae, Neocosmospora vasinfecta, and Fusarium solani grown in malt extract broth were toxic to J2, whereas filtrates from Exophiala pisciphila, Fusarium oxysporum, Gliocladium catenulatum, Pyrenochaeta terrestris, Verticillium chlamydosporium, and sterile fungi 1 and 2 were not toxic to J2. Filtrates of P. lilacinus, S. heteroderae, and N. vasinfecta grown in malt extract broth reduced egg viability, whereas F. oxysporum and P. terrestris filtrates had no effect on egg viability.
PubMed: 19270965
DOI: No ID Found -
Microorganisms Apr 2024In the continuous cropping of , the pathogenic fungi in the rhizosphere soil increased and infected the roots of , resulting in a decrease in yield. This is an urgent...
In the continuous cropping of , the pathogenic fungi in the rhizosphere soil increased and infected the roots of , resulting in a decrease in yield. This is an urgent problem that needs to be solved in order to effectively overcome the obstacles associated with the continuous cropping of . Previous studies have shown that inhibits pathogenic fungi in the rhizosphere of , but the inhibitory effect was not stable. Therefore, we hope to introduce biochar to help colonize in soil. In the experiment, fields planted with for 5 years were renovated, and biochar was mixed in at the same time. The applied amount of biochar was set to four levels (B0, 10 kg·hm; B1, 80 kg·hm; B2, 110 kg·hm; B3, 140 kg·hm), and biological agent was set to three levels (C1, 10 kg·hm; C2, 15 kg·hm; C3, 25 kg·hm). The full combination experiment and a blank control group (CK) were used. The experimental results show that the overall decreased by 0.86%~65.68% at the phylum level. increased by -73.81%~138.47%, and increased by -51.27%~403.20%. At the genus level, increased by -10.29%~855.44%, decreased by 35.02%~86.79%, and increased by -93.60%~680.62%. mainly causes acute bacterial wilt root rot, while mainly causes yellow rot. Under different treatments, the Shannon index increased by -6.77%~62.18%, the Chao1 index increased by -12.07%~95.77%, the Simpson index increased by -7.31%~14.98%, and the ACE index increased by -11.75%~96.12%. The good_coverage indices were all above 0.99. The results of a random forest analysis indicated that , , and were the top three most important species in the soil, with MeanDecreaseGini values of 2.70, 2.50, and 2.45, respectively. , the primary pathogen of , ranked fifth, and its MeanDecreaseGini value was 2.28. The experimental results showed that the B2C2 treatment had the best inhibitory effect on , and the relative abundance of in rhizosphere soil decreased by 86.79% under B2C2 treatment; the B1C2 treatment had the best inhibitory effect on , and the relative abundance of in the rhizosphere soil decreased by 93.60% under B1C2 treatment. Therefore, if we want to improve the soil with acute Ralstonia solanacearum root rot, we should use the B2C2 treatment to improve the soil environment; if we want to improve the soil with yellow rot disease, we should use the B1C2 treatment to improve the soil environment.
PubMed: 38674727
DOI: 10.3390/microorganisms12040783 -
Journal of Natural Products Feb 2016A central challenge of natural products research is assigning bioactive compounds from complex mixtures. The gold standard approach to address this challenge,...
A central challenge of natural products research is assigning bioactive compounds from complex mixtures. The gold standard approach to address this challenge, bioassay-guided fractionation, is often biased toward abundant, rather than bioactive, mixture components. This study evaluated the combination of bioassay-guided fractionation with untargeted metabolite profiling to improve active component identification early in the fractionation process. Key to this methodology was statistical modeling of the integrated biological and chemical data sets (biochemometric analysis). Three data analysis approaches for biochemometric analysis were compared, namely, partial least-squares loading vectors, S-plots, and the selectivity ratio. Extracts from the endophytic fungi Alternaria sp. and Pyrenochaeta sp. with antimicrobial activity against Staphylococcus aureus served as test cases. Biochemometric analysis incorporating the selectivity ratio performed best in identifying bioactive ions from these extracts early in the fractionation process, yielding altersetin (3, MIC 0.23 μg/mL) and macrosphelide A (4, MIC 75 μg/mL) as antibacterial constituents from Alternaria sp. and Pyrenochaeta sp., respectively. This study demonstrates the potential of biochemometrics coupled with bioassay-guided fractionation to identify bioactive mixture components. A benefit of this approach is the ability to integrate multiple stages of fractionation and bioassay data into a single analysis.
Topics: Alternaria; Anti-Bacterial Agents; Biological Products; Heterocyclic Compounds; Microbial Sensitivity Tests; Molecular Structure; Staphylococcus aureus
PubMed: 26841051
DOI: 10.1021/acs.jnatprod.5b01014 -
Journal of Nematology Apr 1970The plant-parasitic nematode, Neotylenchus linlordi, congregated around colonies or filtrates from mycelia of Gliocladium roseum, Rhizoctonia solani, Pyrenochaeta...
The plant-parasitic nematode, Neotylenchus linlordi, congregated around colonies or filtrates from mycelia of Gliocladium roseum, Rhizoctonia solani, Pyrenochaeta terrestris and Chaetomium indicum. The average time required for the nematodes to reach the fungal colonies ranged from less than 4 hr for G. roseum to 20 hr for R. solani. Nematodes first circled near the point of introduction, then moved toward the fungus or filtrate. Several methods of measuring the response of N. linfordi to G. roseum culture filtrate were evaluated. The response was strongest when the test materials were assayed on an agar disk submerged in water agar and the introduced nematodes suspended in agar in a center well midway between the test materials. Filtrates obtained from cultures of G. roseum incubated between 12 and 21 days in potato dextrose broth, were most active. The attractants were small thermostable molecules, soluble in methyl alcohol and unaffected by pH. A yellow pigment with properties similar to a mixture of aurantiogliocladin, rubrogliocladin, and gliorosein was shown to be one of the active materials. The response of N. linfordi to the G. roseum filtrate was not associated with any nutritive factors which would result in reproduction.
PubMed: 19322281
DOI: No ID Found -
Microbiological Research Jul 2015The community and Cd-resistance of endophytic fungi from roots of Salix variegata Franch. collected from the water-level-fluctuation zone of Three Gorges Reservoir...
The community and Cd-resistance of endophytic fungi from roots of Salix variegata Franch. collected from the water-level-fluctuation zone of Three Gorges Reservoir Region, China, were investigated. A total of 53 strains were isolated and identified to 13 morphotaxa, in which Chromosporium, Fusarium and Gonatobotrys were dominant genera. Among them, 27 isolates were selected to measure their resistance to 0.02 mg ml(-1) Cd(2+) and 11 were growth stimulated (Tolerance index>100%). Of these active isolates, four dark septate endophyte (DSE) isolates (Paraphaeosphaeria sp. SR46, Pyrenochaeta sp. SR35, Rhizopycnis vagum SR37 and R. vagum SR44) were further tested for minimum inhibitory concentrations (MICs) against Cd and SR46 was found to be the most tolerant isolate with MIC of 0.39 mg ml(-1). Additionally, the maximum uptake values of these DSEs ranged from 3.01 to 7.89 mg g(-1), but there was no significant correlation between metal uptake with fungal biomass and metal tolerance. Subsequently, a pot experiment was conducted for investigating the impact of SR46 on corn seedlings in Cd-enriched soil. The results obtained suggested that SR46 reduced the Cd bioaccumulation of plant under low (100 mg kg(-1)) Cd stress and enhanced the Cd translocation from root zone to aerial parts under high (200 mg kg(-1)) Cd stress. Besides, it promoted plant growth without Cd stress. These findings indicated S. variegata harbors an endophytic fungal flora showing a high genetic diversity as well as a high level of metal resistance to Cd that has potential values in cadmium cycling and restoration of plant, soil and water system.
Topics: Cadmium; China; Drug Resistance, Fungal; Endophytes; Fungi; Microbial Sensitivity Tests; Plant Roots; Salix; Zea mays
PubMed: 26070690
DOI: 10.1016/j.micres.2015.03.013 -
Plant Diversity Feb 2017var. s is an important medicinal plant with abundant saponins that are widely used in the pharmaceuticals industry. It is unclear why the levels of active ingredients...
var. s is an important medicinal plant with abundant saponins that are widely used in the pharmaceuticals industry. It is unclear why the levels of active ingredients increase as these plants age. We speculated that the concentrations of those components in the rhizomes are mediated by fungal endophytes. To test this hypothesis, we took both culture-dependent and -independent (metagenomics) approaches to analyze the communities of endophytic fungi that inhabit those rhizomes in plants of different age classes (four, six, and eight years old). In all, 147 isolates representing 18 fungal taxa were obtained from 270 segments (90 per age class). Based on morphological and genetic characteristics, (46.55% frequency of occurrence) was the predominant endophyte, followed by sp. (8.66%) and (6.81%). Colonization of endophytic fungi was maximized in the eight-year-old rhizomes (33.33%) when compared with four-year-old (21.21%) and six-year-old (15.15%) rhizomes. Certain fungal species were present only at particular ages. For example, sp., sp., sp., , sp., , , and were found only in the oldest plants. Analysis of (metagenomics) community DNA extracted from different-aged samples revealed that, at the class level, the majority of fungi had the highest sequence similarity to members of Sordariomycetes, followed by Eurotiomycetes and Saccharomycetes. These results were mostly in accord with those we obtained using culture methods. Fungal diversity and richness also changed over time. Our investigation is the first to show that the diversity of fungi in rhizomes of var. is altered as plants age, and our findings provide a foundation for future examinations of useful compounds.
PubMed: 30159492
DOI: 10.1016/j.pld.2016.11.006 -
Genetics and Molecular Research : GMR Feb 2010DNA isolation from some fungal organisms of agronomic importance is difficult because they have cell walls or capsules that are relatively unsusceptible to lysis. We...
DNA isolation from some fungal organisms of agronomic importance is difficult because they have cell walls or capsules that are relatively unsusceptible to lysis. We have developed a fast DNA isolation protocol for Fusarium oxysporum, which causes fusarium wilt disease in more than 100 plant species, and for Pyrenochaeta terrestris, which causes pink root in onions. This protocol was based on the sodium dodecyl sulfate/phenol method, without beta-mercaptoethanol and without maceration in liquid nitrogen; it uses phenol/chloroform extraction to remove proteins and co-precipitated polysaccharides. The A(260/280) absorbance ratios of isolated DNA were around 1.9, suggesting that the DNA fraction was pure and may be used for further analysis. Additionally, the A(260/230) values were higher than 1.8, suggesting negligible contamination by polysaccharides. The DNA isolated by this protocol is of sufficient quality for molecular applications; this technique could be applied to other organisms that have similar substances that hinder DNA extraction.
Topics: DNA, Fungal; Electrophoresis, Agar Gel; Fungi; Molecular Biology; Plants; Polymerase Chain Reaction
PubMed: 20198572
DOI: 10.4238/vol9-1gmr680 -
PloS One 2013Oilseed rape (OSR) grown in monoculture shows a decline in yield relative to virgin OSR of up to 25%, but the mechanisms responsible are unknown. A long term field...
Oilseed rape (OSR) grown in monoculture shows a decline in yield relative to virgin OSR of up to 25%, but the mechanisms responsible are unknown. A long term field experiment of OSR grown in a range of rotations with wheat was used to determine whether shifts in fungal and bacterial populations of the rhizosphere and bulk soil were associated with the development of OSR yield decline. The communities of fungi and bacteria in the rhizosphere and bulk soil from the field experiment were profiled using terminal restriction fragment length polymorphism (TRFLP) and sequencing of cloned internal transcribed spacer regions and 16S rRNA genes, respectively. OSR cropping frequency had no effect on rhizosphere bacterial communities. However, the rhizosphere fungal communities from continuously grown OSR were significantly different to those from other rotations. This was due primarily to an increase in abundance of two fungi which showed 100% and 95% DNA identity to the plant pathogens Olpidium brassicae and Pyrenochaeta lycopersici, respectively. Real-time PCR confirmed that there was significantly more of these fungi in the continuously grown OSR than the other rotations. These two fungi were isolated from the field and used to inoculate OSR and Brassica oleracea grown under controlled conditions in a glasshouse to determine their effect on yield. At high doses, Olpidium brassicae reduced top growth and root biomass in seedlings and reduced branching and subsequent pod and seed production. Pyrenochaeta sp. formed lesions on the roots of seedlings, and at high doses delayed flowering and had a negative impact on seed quantity and quality.
Topics: Agriculture; Biodiversity; Brassica rapa; Crops, Agricultural; DNA, Fungal; DNA, Ribosomal Spacer; Fungi; Molecular Typing; Mycological Typing Techniques; Plant Diseases; Plant Roots; Polymorphism, Restriction Fragment Length; Rhizosphere; Seeds; Sequence Analysis, DNA; Soil Microbiology
PubMed: 23573215
DOI: 10.1371/journal.pone.0059859 -
Plant Disease Jun 2000Five isolates of Curvularia inaequalis were obtained from blighted leaves of zoysia grass. The optimal growth temperature of the pathogen was 30°C and all isolates...
Five isolates of Curvularia inaequalis were obtained from blighted leaves of zoysia grass. The optimal growth temperature of the pathogen was 30°C and all isolates caused foliar blighting symptoms on zoysia grass, bent grass, and bermuda grass. Phytotoxic substances were associated with pathogenicity. Two phytotoxins were isolated from liquid cultures of C. inaequalis by ethyl acetate extraction and repeated silica gel column chromatography. On the basis of mass and nuclear magnetic resonance spectral analyses, the compounds were identified as pyrenocines A and B, phytotoxins produced by Pyrenochaeta terrestris. Pyrenocine A caused leaf necrosis in a leaf-wounding bioassay and inhibited growth of all plants tested in a whole plant test. Large crab grass and fall panicum were most susceptible to pyrenocine A. Pyrenocines A and B also caused significant electrolyte leakage from leaf tissues of bermuda grass. Pyrenocine B exhibited much weaker phytotoxic activity than pyrenocine A in all bioassays performed. Both compounds caused leaf tip dieback symptoms in turf grass plants similar to symptoms observed in the field. Thus, pyrenocines A and B are thought to be involved in the development of Curvularia blight disease of turfgrasses caused by C. inaequalis.
PubMed: 30841112
DOI: 10.1094/PDIS.2000.84.6.684 -
Medical Mycology Case Reports Sep 2023A mycotic infection manifesting as abdominal distension with free serous fluid accumulation in the coelomic cavity is documented in farmed rainbow trout. Histological...
A mycotic infection manifesting as abdominal distension with free serous fluid accumulation in the coelomic cavity is documented in farmed rainbow trout. Histological examination using PAS and silver staining revealed the presence of numerous fungal hyphae in the spleen and gastrointestinal wall. The isolated fungus was sterile and identified by using phylogenetic analysis based on four loci as . This is the first time this fungus has been reported as pathogen.
PubMed: 37274730
DOI: 10.1016/j.mmcr.2023.05.001