scholarly journals Ecological Complexity and the Success of Fungal Biological Control Agents

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Guy R. Knudsen ◽  
Louise-Marie C. Dandurand
Keyword(s):  
Biological Control ◽  
Complex Systems ◽  
Laser Scanning ◽  
Plant Pathogens ◽  
Interspecific Interactions ◽  
Laser Scanning Microscopy ◽  
Biocontrol Agents ◽  
Confocal Laser ◽  
Marker Genes ◽  
Biological Control Agents

Fungal biological control agents against plant pathogens, especially those in soil, operate within physically, biologically, and spatially complex systems by means of a variety of trophic and nontrophic interspecific interactions. However, the biocontrol agents themselves are also subject to the same types of interactions, which may reduce or in some cases enhance their efficacy against target plant pathogens. Characterization of these ecologically complex systems is challenging, but a number of tools are available to help unravel this complexity. Several of these tools are described here, including the use of molecular biology to generate biocontrol agents with useful marker genes and then to quantify these agents in natural systems, epifluorescence and confocal laser scanning microscopy to observe their presence and activity in situ, and spatial statistics and computer simulation modeling to evaluate and predict these activities in heterogeneous soil habitats.

scholarly journals Microplastics accumulate fungal pathogens in terrestrial ecosystems

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gerasimos Gkoutselis ◽  
Stephan Rohrbach ◽  
Janno Harjes ◽  
Martin Obst ◽  
Andreas Brachmann ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Laser Scanning ◽  
Plant Pathogens ◽  
Fungal Infections ◽  
Terrestrial Ecosystems ◽  
Plastic Waste ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Human Pathogens ◽  
Human Environment

AbstractMicroplastic (MP) is a pervasive pollutant in nature that is colonised by diverse groups of microbes, including potentially pathogenic species. Fungi have been largely neglected in this context, despite their affinity for plastics and their impact as pathogens. To unravel the role of MP as a carrier of fungal pathogens in terrestrial ecosystems and the immediate human environment, epiplastic mycobiomes from municipal plastic waste from Kenya were deciphered using ITS metabarcoding as well as a comprehensive meta-analysis, and visualised via scanning electron as well as confocal laser scanning microscopy. Metagenomic and microscopic findings provided complementary evidence that the terrestrial plastisphere is a suitable ecological niche for a variety of fungal organisms, including important animal and plant pathogens, which formed the plastisphere core mycobiome. We show that MPs serve as selective artificial microhabitats that not only attract distinct fungal communities, but also accumulate certain opportunistic human pathogens, such as cryptococcal and Phoma-like species. Therefore, MP must be regarded a persistent reservoir and potential vector for fungal pathogens in soil environments. Given the increasing amount of plastic waste in terrestrial ecosystems worldwide, this interrelation may have severe consequences for the trans-kingdom and multi-organismal epidemiology of fungal infections on a global scale.

scholarly journals Enhanced Antibiofilm Effects of N2 Plasma-Treated Buffer Combined with Antimicrobial Hexapeptides Against Plant Pathogens

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1992 ◽  
Author(s):  
Bohyun Kim ◽  
Hyemi Seo ◽  
Jin Hyung Lee ◽  
Sunghyun Kim ◽  
Won Il Choi ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Crop Production ◽  
Laser Scanning ◽  
Plant Pathogens ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Inactivation ◽  
Imaging Data ◽  
Microscopy Imaging ◽  
N2 Plasma

Suppression of pathogenic bacterial growth to increase food and agricultural productivity is important. We previously developed novel hexapeptides (KCM12 and KCM21) with antimicrobial activities against various phytopathogenic bacteria and N2 plasma-treated buffer (NPB) as an alternative method for bacterial inactivation and as an antibiofilm agent of crops. Here, we developed an enhanced antibiofilm method based on antimicrobial hexapeptides with N2 plasma-treated buffer against plant pathogens. Our results demonstrated that hexapeptides effectively inhibited the growth of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and the biofilm it formed. Potent biofilm formation-inhibiting effects of hexapeptides were observed at concentrations of above 20 µM, and samples treated with hexapeptide above 100 µM reduced the ability of the bacteria to produce biofilm by 80%. 3D confocal laser scanning microscopy imaging data revealed that the antimicrobial activity of hexapeptides was enough to affect the cells embedded inside the biofilm. Finally, combination treatment with NPB and antimicrobial hexapeptides increased the antibiofilm effect compared with the effect of single processing against multilayered plant pathogen biofilms. These findings show that the combination of hexapeptides and NPB can be potentially applied for improving crop production.

scholarly journals Phytohormone Priming of Tomato Plants Evoke Differential Behavior in Rhizoctonia solani During Infection, With Salicylate Priming Imparting Greater Tolerance Than Jasmonate

2022 ◽  
Vol 12 ◽  
Author(s):  
Paulami Koley ◽  
Subhadip Brahmachari ◽  
Amitava Saha ◽  
Camelia Deb ◽  
Monimala Mondal ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Laser Scanning ◽  
Time Course ◽  
Green Fluorescence Protein ◽  
Laser Scanning Microscopy ◽  
Early Infection ◽  
Confocal Laser ◽  
Marker Genes ◽  
Necrotrophic Pathogen ◽  
Tomato Plants

In the field of phytohormone defense, the general perception is that salicylate (SA)-mediated defense is induced against biotrophic pathogens while jasmonate (JA)-mediated defense functions against necrotrophic pathogens. Our goals were to observe the behavior of the necrotrophic pathogen Rhizoctonia solani in the vicinity, on the surface, and within the host tissue after priming the host with SA or JA, and to see if priming with these phytohormones would affect the host defense differently upon infection. It was observed for the first time, that R. solani could not only distinguish between JA versus SA-primed tomato plants from a distance, but surprisingly avoided SA-primed plants more than JA-primed plants. To corroborate these findings, early infection events were monitored and compared through microscopy, Scanning Electron Microscopy, and Confocal Laser Scanning Microscopy using transformed R. solani expressing green fluorescence protein gene (gfp). Different histochemical and physiological parameters were compared between the unprimed control, JA-primed, and SA-primed plants after infection. The expression of a total of fifteen genes, including the appressoria-related gene of the pathogen and twelve marker genes functioning in the SA and JA signaling pathways, were monitored over a time course during early infection stages. R. solani being traditionally designated as a necrotroph, the major unexpected observations were that Salicylate priming offered better tolerance than Jasmonate priming and that it was mediated through the activation of SA-mediated defense during the initial phase of infection, followed by JA-mediated defense in the later phase. Hence, the present scenario of biphasic SA-JA defense cascades during R. solani infection, with SA priming imparting maximum tolerance, indicate a possible hemibiotrophic pathosystem that needs to be investigated further.

scholarly journals Specific Mycoparasite-Fusarium Graminearum Molecular Signatures in Germinating Seeds Disabled Fusarium Head Blight Pathogen’s Infection

2021 ◽  
Vol 22 (5) ◽  
pp. 2461
Author(s):  
Seon Hwa Kim ◽  
Rachid Lahlali ◽  
Chithra Karunakaran ◽  
Vladimir Vujanovic
Keyword(s):  
Fusarium Head Blight ◽  
Fusarium Graminearum ◽  
Laser Scanning ◽  
Plant Pathogens ◽  
Principal Component ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Molecular Signatures ◽  
Head Blight ◽  
Protein Secondary Structures

Advances in Infrared (IR) spectroscopies have entered a new era of research with applications in phytobiome, plant microbiome and health. Fusarium graminearum 3-ADON is the most aggressive mycotoxigenic chemotype causing Fusarium head blight (FHB) in cereals; while Sphaerodes mycoparasitica is the specific Fusarium mycoparasite with biotrophic lifestyle discovered in cereal seeds and roots. Fourier transform infrared (FTIR) spectroscopy analyses depicted shifts in the spectral peaks related to mycoparasitism mainly within the region of proteins, lipids, also indicating a link between carbohydrates and protein regions, involving potential phenolic compounds. Especially, S. mycoparasitica contributes to significant changes in lipid region 3050–2800 cm−1, while in the protein region, an increasing trend was observed for the peaks 1655–1638 cm−1 (amide I) and 1549–1548 cm−1 (amide II) with changes in indicative protein secondary structures. Besides, the peak extending on the region 1520–1500 cm−1 insinuates a presence of aromatic compounds in presence of mycoparasite on the F. graminearum root sample. Monitoring shift in improved seed germination, fungus-fungus interface through scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), and FTIR molecular signatures combined with principal component analysis (PCA) proved useful tools to detect an early mycoparasitism as a vital asset of the preventive biocontrol strategy against plant pathogens.

scholarly journals Biopolymers for Biological Control of Plant Pathogens: Advances in Microencapsulation of Beneficial Microorganisms

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1938
Author(s):  
Roohallah Saberi-Riseh ◽  
Mojde Moradi-Pour ◽  
Reza Mohammadinejad ◽  
Vijay Kumar Thakur
Keyword(s):  
Biological Control ◽  
Controlled Release ◽  
Shelf Life ◽  
Plant Pathogens ◽  
Mineral Fertilizer ◽  
Polymeric Materials ◽  
Soil Characteristics ◽  
Biocontrol Agents ◽  
Biological Control Agents ◽  
Microbial Agents

The use of biofertilizers, including biocontrol agents such as Pseudomonas and Bacillus in agriculture can increase soil characteristics and plant acquisition of nutrients and enhancement the efficiency of manure and mineral fertilizer. Despite the problems that liquid and solid formulations have in maintaining the viability of microbial agents, encapsulation can improve their application with extended shelf-life, and controlled release from formulations. Research into novel formulation methods especially encapsulation techniques has increased in recent years due to the mounting demand for microbial biological control. The application of polymeric materials in agriculture has developed recently as a replacement for traditional materials and considered an improvement in technological processes in the growing of crops. This study aims to overview of types of biopolymers and methods used for encapsulation of living biological control agents, especially microbial organisms.

scholarly journals Spatiotemporal Colonization of Xylella fastidiosa in its Vector Supports the Role of Egestion in the Inoculation Mechanism of Foregut-Borne Plant Pathogens

2011 ◽  
Vol 101 (8) ◽  
pp. 912-922 ◽  
Author(s):  
Elaine A. Backus ◽  
David J. W. Morgan
Keyword(s):  
Laser Scanning ◽  
Plant Pathogens ◽  
Fluorescent Protein ◽  
Xylella Fastidiosa ◽  
Functional Anatomy ◽  
Laser Scanning Microscopy ◽  
Microbial Colonization ◽  
Confocal Laser ◽  
Spatiotemporal Pattern ◽  
Homalodisca Vitripennis

The pathogen that causes Pierce's disease of grapevine, Xylella fastidiosa, is the only known bacterial, arthropod-transmitted plant pathogen that does not circulate in the vector's hemolymph. Instead, bacteria are foregut-borne, persistent in adult vectors but semipersistent in immatures (i.e., bacteria colonize cuticular surfaces of the anterior foregut, are retained for hours to days, but are lost during molting). Yet, exactly how a sharpshooter vector inoculates bacteria from foregut acquisition sites is unknown. The present study used confocal laser-scanning microscopy to identify locations in undissected, anterior foreguts of the glassy-winged sharpshooter colonized by green fluorescent protein-expressing X. fastidiosa. Spatial and temporal distributions of colonizing X. fastidiosa were examined daily over acquisition access periods of 1 to 6 days for both contaminated field-collected and clean laboratory-reared Homalodisca vitripennis. Results provide the first direct, empirical evidence that established populations of X. fastidiosa can disappear from vector foreguts over time. When combined with existing knowledge on behavior, physiology, and functional anatomy of sharpshooter feeding, present results support the idea that the disappearance is caused by outward fluid flow (egestion) not inward flow (ingestion) (i.e., swallowing). Thus, results support the hypothesis that egestion is a critical part of the X. fastidiosa inoculation mechanism. Furthermore, results suggest a cyclical, spatiotemporal pattern of microbial colonization, disappearance, and recolonization in the precibarium. Colonization patterns also support two types of egestion, termed rinsing and discharging egestion herein. Finally, comparison of acquisition results for field-collected versus laboratory-reared sharpshooters suggest that there may be competitive binding for optimum acquisition sites in the foregut. Therefore, successful inoculation of X. fastidiosa may depend, in large part, on vector load in the precibarium.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

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