scholarly journals Improved Microassays Used to Test Natural Product-Based and Conventional Fungicides on Plant Pathogenic Fungi

Plant Disease ◽  
2008 ◽  
Vol 92 (1) ◽  
pp. 106-112 ◽  
Author(s):  
Maritza Abril ◽  
Kenneth J. Curry ◽  
Barbara J. Smith ◽  
David E. Wedge

Seven important plant pathogenic fungi (Botrytis cinerea, Colletotrichum acutatum, C. fragariae, C. gloeosporioides, Fusarium oxysporum, Phomopsis obscurans, and P. viticola) valuable in screening fungicides were tested. Our procedure included washing conidia to reduce germination times, incorporating Roswell Park Memorial Institute 1640 as a medium of known composition, and using coverslips in the 24-well cell culture clusters to document the effect of fungicides on fungal morphology. The natural product-based fungicide, sampangine, a sampangine analog, 4-bromosampangine, plus seven conventional fungicides (benomyl, captan, cyprodinil, fenbuconazole, fenhexamid, iprodione, and kresoxim-methyl) were tested in vitro for their ability to inhibit germination and growth of the seven fungal species. Sampangine inhibited germination in all fungi except C. acutatum. Comparison of results of germination and morphology microbioassays with results of microtiter assays suggests that some fungicides stop fungal germination, whereas others only slow down fungal growth. We hypothesize that sampangine, except against C. acutatum, has the same physical mode of action, germination inhibition, as the conventional fungicides captan, iprodione, and kresoxim-methyl. 4-Bromosampangine caused morphological anomalies including excessive branching of germ tubes of C. fragariae and splaying and branching of germ tubes of B. cinerea.

1999 ◽  
Vol 65 (3) ◽  
pp. 1320-1324 ◽  
Author(s):  
Zhi-Yuan Chen ◽  
Robert L. Brown ◽  
Alan R. Lax ◽  
Thomas E. Cleveland ◽  
John S. Russin

ABSTRACT The cDNA of a 14-kDa trypsin inhibitor (TI) from corn was subcloned into an Escherichia coli overexpression vector. The overexpressed TI was purified based on its insolubility in urea and then refolded into the active form in vitro. This recombinant TI inhibited both conidium germination and hyphal growth of all nine plant pathogenic fungi studied, including Aspergillus flavus,Aspergillus parasiticus, and Fusarium moniliforme. The calculated 50% inhibitory concentration of TI for conidium germination ranged from 70 to more than 300 μg/ml, and that for fungal growth ranged from 33 to 124 μg/ml depending on the fungal species. It also inhibited A. flavus and F. moniliforme simultaneously when they were tested together. The results suggest that the corn 14-kDa TI may function in host resistance against a variety of fungal pathogens of crops.


Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 737
Author(s):  
Marina Pekmezovic ◽  
Melina Kalagasidis Krusic ◽  
Ivana Malagurski ◽  
Jelena Milovanovic ◽  
Karolina Stępień ◽  
...  

Novel biodegradable and biocompatible formulations of “old” but “gold” drugs such as nystatin (Nys) and amphotericin B (AmB) were made using a biopolymer as a matrix. Medium chain length polyhydroxyalkanoates (mcl-PHA) were used to formulate both polyenes (Nys and AmB) in the form of films (~50 µm). Thermal properties and stability of the materials were not significantly altered by the incorporation of polyenes in mcl-PHA, but polyene containing materials were more hydrophobic. These formulations were tested in vitro against a panel of pathogenic fungi and for antibiofilm properties. The films containing 0.1 to 2 weight % polyenes showed good activity and sustained polyene release for up to 4 days. A PHA monomer, namely 3-hydroxydecanoic acid (C10-OH), was added to the films to achieve an enhanced synergistic effect with polyenes against fungal growth. Mcl-PHA based polyene formulations showed excellent growth inhibitory activity against both Candida yeasts (C. albicans ATCC 1023, C. albicans SC5314 (ATCC MYA-2876), C. parapsilosis ATCC 22019) and filamentous fungi (Aspergillus fumigatus ATCC 13073; Trichophyton mentagrophytes ATCC 9533, Microsporum gypseum ATCC 24102). All antifungal PHA film preparations prevented the formation of a C. albicans biofilm, while they were not efficient in eradication of mature biofilms, rendering them suitable for the transdermal application or as coatings of implants.


2020 ◽  
Vol 21 (22) ◽  
pp. 8681
Author(s):  
Nicolò Orsoni ◽  
Francesca Degola ◽  
Luca Nerva ◽  
Franco Bisceglie ◽  
Giorgio Spadola ◽  
...  

As key players in biotic stress response of plants, jasmonic acid (JA) and its derivatives cover a specific and prominent role in pathogens-mediated signaling and hence are promising candidates for a sustainable management of phytopathogenic fungi. Recently, JA directed antimicrobial effects on plant pathogens has been suggested, supporting the theory of oxylipins as double gamers in plant-pathogen interaction. Based on these premises, six derivatives (dihydrojasmone and cis-jasmone, two thiosemicarbazonic derivatives and their corresponding complexes with copper) have been evaluated against 13 fungal species affecting various economically important herbaceous and woody crops, such as cereals, grapes and horticultural crops: Phaeoacremonium minimum, Neofusicoccum parvum, Phaeomoniella chlamydospora, Fomitiporia mediterranea, Fusarium poae, F. culmorum, F. graminearum, F. oxysporum f. sp. lactucae,F. sporotrichioides, Aspergillus flavus, Rhizoctonia solani,Sclerotinia spp. and Verticillium dahliae. The biological activity of these compounds was assessed in terms of growth inhibition and, for the two mycotoxigenic species A. flavus and F. sporotrichioides, also in terms of toxin containment. As expected, the inhibitory effect of molecules greatly varied amongst both genera and species; cis-jasmone thiosemicarbazone in particular has shown the wider range of effectiveness. However, our results show that thiosemicarbazones derivatives are more effective than the parent ketones in limiting fungal growth and mycotoxins production, supporting possible applications for the control of pathogenic fungi.


2020 ◽  
Vol 8 (1) ◽  
pp. 69 ◽  
Author(s):  
Marco Camardo Leggieri ◽  
Amedeo Pietri ◽  
Paola Battilani

No information is available in the literature about the influence of temperature (T) on Penicillium and Aspergillus spp. growth and mycotoxin production on cheese rinds. The aim of this work was to: (i) study fungal ecology on cheese in terms of T requirements, focusing on the partitioning of mycotoxins between the rind and mycelium; and (ii) validate predictive models previously developed by in vitro trials. Grana cheese rind blocks were inoculated with A. versicolor, P. crustosum, P. nordicum, P. roqueforti, and P. verrucosum, incubated at different T regimes (10–30 °C, step 5 °C) and after 14 days the production of mycotoxins (ochratoxin A (OTA); sterigmatocystin (STC); roquefortine C (ROQ-C), mycophenolic acid (MPA), Pr toxin (PR-Tox), citrinin (CIT), cyclopiazonic acid (CPA)) was quantified. All the fungi grew optimally around 15–25 °C and produced the expected mycotoxins (except MPA, Pr-Tox, and CIT). The majority of the mycotoxins produced remained in the mycelium (~90%) in three out of five fungal species (P. crustosum, P. nordicum, and P. roqueforti); the opposite occurred for A. versicolor and P. verrucosum with 71% and 58% of STC and OTA detected in cheese rind, respectively. Available predictive models fitted fungal growth on the cheese rind well, but validation was not possible for mycotoxins because they were produced in a very narrow T range.


2020 ◽  
Vol 21 (21) ◽  
pp. 7912 ◽  
Author(s):  
Tatyana Odintsova ◽  
Larisa Shcherbakova ◽  
Marina Slezina ◽  
Tatyana Pasechnik ◽  
Bakhyt Kartabaeva ◽  
...  

Hevein-like antimicrobial peptides (AMPs) comprise a family of plant AMPs with antifungal activity, which harbor a chitin-binding site involved in interactions with chitin of fungal cell walls. However, the mode of action of hevein-like AMPs remains poorly understood. This work reports the structure–function relationship in WAMPs—hevein-like AMPs found in wheat (Triticum kiharae Dorof. et Migush.) and later in other Poaceae species. The effect of WAMP homologues differing at position 34 and the antifungal activity of peptide fragments derived from the central, N- and C-terminal regions of one of the WAMPs, namely WAMP-2, on spore germination of different plant pathogenic fungi were studied. Additionally, the ability of WAMP-2-derived peptides to potentiate the fungicidal effect of tebuconazole, one of the triazole fungicides, towards five cereal-damaging fungi was explored in vitro by co-application of WAMP-2 fragments with Folicur® EC 250 (25% tebuconazole). The antifungal activity of WAMP homologues and WAMP-2-derived peptides varied depending on the fungus, suggesting multiple modes of action for WAMPs against diverse pathogens. Folicur® combined with the WAMP-2 fragments inhibited the spore germination at a much greater level than the fungicide alone, and the type of interactions was either synergistic or additive, depending on the target fungus and concentration combinations of the compounds. The combinations, which resulted in synergism and drastically enhanced the sensitivity to tebuconazole, were revealed for all five fungi by a checkerboard assay. The ability to synergistically interact with a fungicide and exacerbate the sensitivity of plant pathogenic fungi to a commercial antifungal agent is a novel and previously uninvestigated property of hevein-like AMPs.


Apidologie ◽  
2019 ◽  
Vol 50 (6) ◽  
pp. 871-880 ◽  
Author(s):  
Jorgiane B. Parish ◽  
Eileen S. Scott ◽  
Raymond Correll ◽  
Katja Hogendoorn

AbstractHoney bees, Apis mellifera, have been implicated as vectors of plant pathogens. However, the survival of spores of plant pathogenic fungi through the digestive tract of workers has not been investigated. As workers defecate outside the hive, transport of hives could give rise to biosecurity concerns if fungal spores remain viable following passage through the digestive tract. To determine the likelihood that honey bees serve as vectors, this study investigated the viability of spores of Botrytis cinerea and Colletotrichum acutatum after passing through the digestive tract of summer and autumn worker bees. For both fungi, the mean viability of spores in faeces suspensions was less than one percent of the initial dose fed to the bees. Although survival was low, the large number of workers per hive implies a high probability of transmission of viable spores through honey bee faeces. Hence, in the case of economically important fungal diseases, transported hives could be a source of inoculum and quarantine restrictions should be considered.


2014 ◽  
Vol 53 (4) ◽  
pp. 438-440
Author(s):  
Liliana Gallez ◽  
Mirta Kiehr ◽  
Leticia Fernández ◽  
Rolf Delhey ◽  
Débora Stikar

Plant Disease ◽  
2009 ◽  
Vol 93 (10) ◽  
pp. 1037-1043 ◽  
Author(s):  
Young-Ki Jo ◽  
Byung H. Kim ◽  
Geunhwa Jung

Silver in ionic or nanoparticle forms has a high antimicrobial activity and is therefore widely used for various sterilization purposes including materials of medical devices and water sanitization. There have been relatively few studies on the applicability of silver to control plant diseases. Various forms of silver ions and nanoparticles were tested in the current study to examine the antifungal activity on two plant-pathogenic fungi, Bipolaris sorokiniana and Magnaporthe grisea. In vitro petri dish assays indicated that silver ions and nanoparticles had a significant effect on the colony formation of these two pathogens. Effective concentrations of the silver compounds inhibiting colony formation by 50% (EC50) were higher for B. sorokiniana than for M. grisea. The inhibitory effect on colony formation significantly diminished after silver cations were neutralized with chloride ions. Growth chamber inoculation assays further confirmed that both ionic and nanoparticle silver significantly reduced these two fungal diseases on perennial ryegrass (Lolium perenne). Particularly, silver ions and nanoparticles effectively reduced disease severity with an application at 3 h before spore inoculation, but their efficacy significantly diminished when applied at 24 h after inoculation. The in vitro and in planta evaluations of silver indicated that both silver ions and nanoparticles influence colony formation of spores and disease progress of plant-pathogenic fungi. In planta efficacy of silver ions and nanoparticles is much greater with preventative application, which may promote the direct contact of silver with spores and germ tubes, and inhibit their viability.


2009 ◽  
Vol 64 (11-12) ◽  
pp. 790-792 ◽  
Author(s):  
Jin-Wen Shen ◽  
Bing-Ji Ma ◽  
Wen Li ◽  
Hai-You Yu ◽  
Ting-Ting Wu ◽  
...  

The methanolic extract of the fruiting bodies of the mushroom Armillariella tabescens was found to show antifungal activity against Gibberella zeae. The active compound was isolated from the fruiting bodies of A. tabescens by bioassay-guided fractionation of the extract and identifi ed as armillarisin B. Armillarisin B eventually corresponds to 2-hydroxy-2- phenylpropanediamide and its structure was confi rmed on the basis of spectroscopic studies including 2D NMR experiments.


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