Douglas-fir root-associated microorganisms with inhibitory activity towards fungal plant pathogens and human bacterial pathogens

1996 ◽  
Vol 42 (7) ◽  
pp. 690-700 ◽  
Author(s):  
Paige E. Axelrood ◽  
Alison M. Clarke ◽  
Reed Radley ◽  
S. Janet V. Zemcov
Keyword(s):  
Antifungal Activity ◽  
Inhibitory Activity ◽  
Plant Pathogens ◽  
Bacterial Pathogens ◽  
Douglas Fir ◽  
Microbial Culture ◽  
Bacterial Strains ◽  
Fungal Plant Pathogens ◽  
Forest Sites

A microbial culture collection composed of 1820 bacterial strains, including 298 actinomycete strains, was established from the roots of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings harvested from conifer nurseries and forest sites. Two hundred and thirty-four strains inhibited the growth of Fusarium, Cylindrocarpon, and (or) Pythium spp. in in vitro assays. A significantly greater proportion of bacterial strains from actinomycete genera exhibited antifungal properties compared with bacterial strains from nonactinomycete genera. Eighty-nine percent of identified inhibitory strains were Streptomyces, Streptoverticillium, Bacillus, Pseudomonas, or Burkholderia species. The actinomycete species were isolated almost exclusively from forest seedlings. Recovery of inhibitory strains representing 29 microbial species was enhanced using a variety of methods to isolate microorganisms from the roots of seedlings from nursery and forest sites. Bacterial strains (including actinomycete strains) with antifungal activity were tested for in vitro growth inhibition of six clinical human bacterial pathogens (Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa). Forty-eight percent of the tested strains inhibited one or more human pathogens. Inhibitory activity towards fungal and bacterial pathogens was strain specific, not species specific, and many inhibitory strains exhibited broad-spectrum activity. Strains with antifungal activity against several conifer root pathogens were also more likely to inhibit multiple species of clinical bacterial pathogens.Key words: in vitro, antimicrobial, conifer rhizosphere.

Antifungal activity of extracts from endophytic fungi associated with Smallanthus maintained in vitro as autotrophic cultures and as pot plants in the greenhouse

2012 ◽  
Vol 58 (10) ◽  
pp. 1202-1211 ◽  
Author(s):  
Luiz H. Rosa ◽  
Nurhayat Tabanca ◽  
Natascha Techen ◽  
Zhiqiang Pan ◽  
David E. Wedge ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Endophytic Fungi ◽  
Plant Pathogens ◽  
Cultivation Conditions ◽  
Smallanthus Sonchifolius ◽  
Fungal Plant Pathogens ◽  
In The Wild ◽  
Fungal Assemblages ◽  
Pot Plants

The endophytic fungal assemblages associated with Smallanthus sonchifolius (Poepp.) H. Rob. and Smallanthus uvedalius (L.) Mack. ex Small growing in vitro autotrophic cultures and in the greenhouse were identified and evaluated for their ability to produce bioactive compounds. A total of 25 isolates were recovered that were genetically closely related to species of the genera Bionectria , Cladosporium , Colletotrichum , Fusarium , Gibberella , Hypocrea , Lecythophora , Nigrospora , Plectosphaerella , and Trichoderma . The endophytic assemblages of S. sonchifolius presented a greater diversity than the group isolated from S. uvedalius and demonstrated the presence of dominant generalist fungi. Extracts of all fungi were screened against the fungal plant pathogens. Ten extracts (41.6%) displayed antifungal activities; some of them had a broad antifungal activity. The phylotypes Lecythophora sp. 1, Lecythophora sp. 2, and Fusarium oxysporum were isolated from in vitro autotrophic cultures and displayed antifungal activity. The presence of bioactive endophytic fungi within S. sonchifolius and S. uvedalius suggests an ecological advantage against pathogenic attacks. This study revealed reduced numbers of endophytes in association with both Smallanthus species in controlled cultivation conditions compared with the endophytic communities of hosts collected in the wild environments. Even as reduced endophytic communities, these fungi continue to provide chemical protection for the host.

scholarly journals Evaluation of in-vitro methods to select effective streptomycetes against toxigenic fusaria

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6905 ◽  
Author(s):  
Elena Maria Colombo ◽  
Cristina Pizzatti ◽  
Andrea Kunova ◽  
Claudio Gardana ◽  
Marco Saracchi ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Culture Media ◽  
Screening Methods ◽  
Dual Culture ◽  
In Planta ◽  
In Vitro Method ◽  
In Vitro Methods ◽  
Strain Diversity ◽  
Fungal Plant Pathogens

Biocontrol microorganisms are emerging as an effective alternative to pesticides. Ideally, biocontrol agents (BCAs) for the control of fungal plant pathogens should be selected by an in vitro method that is high-throughput and is predictive of in planta efficacy, possibly considering environmental factors, and the natural diversity of the pathogen. The purpose of our study was (1) to assess the effects ofFusariumstrain diversity (N= 5) and culture media (N= 6) on the identification of biological control activity ofStreptomycesstrains (N= 20) againstFusariumpathogens of wheat in vitro and (2) to verify the ability of our in vitro screening methods to simulate the activity in planta. Our results indicate that culture media,Fusariumstrain diversity, and their interactions affect the results of an in vitro selection by dual culture assay. The results obtained on the wheat-based culture media resulted in the highest correlation score (r= 0.5) with the in planta root rot (RR) inhibition, suggesting that this in vitro method was the best predictor of in planta performance of streptomycetes against Fusarium RR of wheat assessed as extension of the necrosis on the root. Contrarily, none of the in vitro plate assays using the media tested could appropriately predict the activity of the streptomycetes against Fusarium foot rot symptoms estimated as the necrosis at the crown level. Considering overall data of correlation, the activity in planta cannot be effectively predicted by dual culture plate studies, therefore improved in vitro methods are needed to better mimic the activity of biocontrol strains in natural conditions. This work contributes to setting up laboratory standards for preliminary screening assays ofStreptomycesBCAs against fungal pathogens.

scholarly journals Plant Defensin Peptides have Antifungal and Antibacterial Activity Against Human and Plant Pathogens

2019 ◽  
Vol 109 (3) ◽  
pp. 402-408 ◽  
Author(s):  
Andrew E. Sathoff ◽  
Siva Velivelli ◽  
Dilip M. Shah ◽  
Deborah A. Samac
Keyword(s):  
Antibacterial Activity ◽  
Plant Pathogens ◽  
Crown Rot ◽  
Plant Defensin ◽  
Core Motif ◽  
Potential Control ◽  
Fungal Plant Pathogens ◽  
Plant Defensins ◽  
Animal Pathogens

Plant defensins are small, cysteine-rich antimicrobial peptides. These peptides have previously been shown to primarily inhibit the growth of fungal plant pathogens. Plant defensins have a γ-core motif, defined as GXCX3-9C, which is required for their antifungal activity. To evaluate plant defensins as a potential control for a problematic agricultural disease (alfalfa crown rot), short, chemically synthesized peptides containing γ-core motif sequences were screened for activity against numerous crown rot pathogens. These peptides showed both antifungal and, surprisingly, antibacterial activity. Core motif peptides from Medicago truncatula defensins (MtDef4 and MtDef5) displayed high activity against both plant and human bacterial pathogens in vitro. Full-length defensins had higher antimicrobial activity compared with the peptides containing their predictive γ-core motifs. These results show the future promise for controlling a wide array of economically important fungal and bacterial plant pathogens through the transgenic expression of a plant defensin. They also suggest that plant defensins may be an untapped reservoir for development of therapeutic compounds for combating human and animal pathogens.

scholarly journals Chemical composition and antifungal activity of essential oils from four Asteraceae plants grown in Egypt

2018 ◽  
Vol 73 (7-8) ◽  
pp. 313-318 ◽  
Author(s):  
Rose Vanessa Bandeira Reidel ◽  
Simona Nardoni ◽  
Francesca Mancianti ◽  
Claudia Anedda ◽  
Abd El-Nasser G. El Gendy ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Antifungal Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Inhibitory Activity ◽  
First Time

Abstract The objective of the present paper was the assessment of the chemical composition of the essential oils from four Asteraceae species with a considerable food, medicinal, and agricultural value, collected in Egypt, together with their in vitro inhibitory activity against molds and yeasts. The essential oil of Launaea cornuta flowers was also evaluated for the first time, but because of its very low yield (<0.01%), no antifungal test was performed.

scholarly journals The Potential Antibacterial and Antifungal Activities of Wood Treated with Withania somnifera Fruit Extract, and the Phenolic, Caffeine, and Flavonoid Composition of the Extract According to HPLC

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 113 ◽  
Author(s):  
Mervat EL-Hefny ◽  
Mohamed Z. M. Salem ◽  
Said I. Behiry ◽  
Hayssam M. Ali
Keyword(s):  
Withania Somnifera ◽  
Plant Pathogens ◽  
Fusarium Culmorum ◽  
Acetone Extract ◽  
Melia Azedarach ◽  
Bacterial Strains ◽  
Fruit Extract ◽  
Pseudomonas Cichorii ◽  
Antibacterial And Antifungal Activities

In the present study, Melia azedarach wood blocks treated with different acetone extract concentrations from Withania somnifera fruits are assessed for their antibacterial and anti-fungal activities. Wood blocks of M. azedarach treated with W. somnifera fruit extract at concentrations of 0, 1, 2, and 3% are evaluated for in vitro antimicrobial activity against five genbank accessioned bacterial strains—Agrobacterium tumefaciens, Dickeya solani, Erwinia amylovora, Pseudomonas cichorii, and Serratia pylumthica—and two fungi, namely, Fusarium culmorum and Rhizoctonia solani. Through HPLC analysis we find that the most abundant quantified phenolic and flavonoid compounds of acetone extract (mg/100 g) are salicylic acid (9.49), vanillic acid (4.78), rutin (4702.58), and myricetin (1386.62). Wood treated with the extract at 2% and 3% show no growth of A. tumefaciens, E. amylovora, and P. cichorii. Use of the extract at 3% causes inhibition of fungal mycelia of F. culmorum and R. solani by 84.07% and 67.03%, respectively. In conclusion, potent antifungal and antibacterial activity against plant pathogens is found when an acetone extract of W. somnifera fruits is applied to wood samples.

scholarly journals Staphylococcus saprophyticus L-38 produces volatile 3,3-dimethyl-1,2-epoxybutane with strong inhibitory activity against Aspergillus flavus germination and aflatoxin production

2020 ◽  
Vol 13 (2) ◽  
pp. 247-258 ◽  
Author(s):  
A.D. Gong ◽  
G.J. Sun ◽  
Z.Y. Zhao ◽  
Y.C. Liao ◽  
J.B. Zhang
Keyword(s):  
Food Safety ◽  
Antifungal Activity ◽  
Aspergillus Flavus ◽  
Plant Pathogens ◽  
Aflatoxin Production ◽  
Gas Chromatography Mass Spectrometry ◽  
Total Peak Area ◽  
Staphylococcus Saprophyticus

Controlling proliferation and aflatoxin production by Aspergillus flavus is a pressing challenge for global food safety and security. Marine bacterium Staphylococcus saprophyticus strain L-38 showed excellent antifungal activity toward A. flavus in vitro and in vivo. In sealed, non-contact confrontation assays, L-38 completely inhibited conidial germination and mycelial growth of A. flavus through the production of volatile organic compounds (VOCs). Gas chromatography-mass spectrometry identified 3,3-dimethyl-1,2-epoxybutane (3-DE) as the most abundant VOC (32.61% of total peak area, 78% matching). Exposure of A. flavus cultures to synthetic 3-DE similarly demonstrated strong inhibition of growth. Moreover, culture of L-38 in a sealed chamber with maize or peanuts artificially inoculated with A. flavus, at high water activity, resulted in significant inhibition of A. flavus germination and aflatoxin biosynthesis. Scanning electron microscopy of these samples revealed severe damage to conidial cells and hyphae compared to samples not exposed to L-38. L-38 also showed broad and effective antifungal activity toward eight other phytopathogenic fungi including Aspergillus niger, Fusarium verticillioides, Fusarium graminearum, Sclerotinia sclerotiorum, Rhizoctonia solani, Alternaria alternata, Monilinia fructicola, and Botrytis cinerea. This work introduces S. saprophyticus L-38 as a potential biocontrol agent and demonstrates the efficacy of the volatile 3-DE in the control of A. flavus and other destructive plant pathogens for post-harvest food safety.

scholarly journals Comparison of Two Commercial Recirculated Aquacultural Systems and Their Microbial Potential in Plant Disease Suppression

2021 ◽  
Author(s):  
Sammar Khalil ◽  
Preeti Panda ◽  
Farideh Ghadamgahi ◽  
AnnaKarin Rosberg ◽  
Ramesh R Vetukuri
Keyword(s):  
Plant Growth ◽  
Fish Species ◽  
Plant Pathogens ◽  
Extracellular Enzymes ◽  
Production Systems ◽  
Sampling Site ◽  
Disease Suppression ◽  
Bacterial Strains ◽  
Promising Tool

Aquaponics are food production systems advocated for food security and health. Their sustainability from a nutritional and plant health perspective is, however, a significant challenge. Recirculated aquaculture systems (RAS) form a major part of aquaponic systems but knowledge about their potential to benefit plant growth and suppress their pathogens is limited. The current study tested if the diversity and function of microbial communities in two commercial RAS were specific to the fish species used (Tilapia or Clarias) and sampling site (fish tanks and wastewaters), and whether they confer benefits to plants and have in vitro antagonistic potential towards plant pathogens. Microbial diversity and composition was found to be dependent on fish species and sample site. The Tilapia RAS hosted higher bacterial diversity than the Clarias RAS; but the latter hosted higher fungal diversity. Both Tilapia and Clarias RAS hosted bacterial and fungal communities that promoted plant growth, inhibited plant pathogens and encouraged biodegradation. The production of extracellular enzymes, related to nutrient availability and pathogen control, by bacterial strains isolated from the Tilapia and Clarias systems, makes them a promising tool in aquaponics and in their system design.

scholarly journals IN-VITROSTUDIES ON ANTIFUNGALACTIVITY OF SOMEMISTLETOE SPECIES

2021 ◽  
Vol 9 (06) ◽  
pp. 420-427
Author(s):  
R. Neelima ◽  
◽  
B. Sujatha ◽  
N.V. Ramana ◽  
B.V. Rao ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Ethyl Acetate ◽  
Phytophthora Infestans ◽  
Inhibitory Activity ◽  
Sclerotium Rolfsii ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
Leaf Extracts

In vitro evaluation of antifungal activity by disc diffusion method was carried out on leaf extracts of D.falcata, D. falcata var pubescens, V. monoicum and V. orientale and stem extracts of D. falcata, D. falcata var pubescens, V. articulatum and V.orientale using three different solvents viz., methanol, n-hexane and ethyl acetate. The antifungal activity was tested on three fungal strains include Fusarium oxysporum, Phytophthora infestans, Sclerotium rolfsii. Overall leaf extracts exerted better inhibitory activity than stem counterparts. Among all, only V. orientale was effective against the three fungal species.Compared to stem extracts, leaf extracts of D. falcata var pubescens have shown higher antifungal activity.

scholarly journals Antifungal activity in vitro of Sapranthus microcarpus (Annonaceae) against phytopathogens

2018 ◽  
Author(s):  
Iván De-la-Cruz-Chacón ◽  
Nora Yazmin López-Fernández ◽  
Christian Anabí Riley-Saldaña ◽  
Marisol Castro Moreno ◽  
Alma Rosa González-Esquinca
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Stem Bark ◽  
Antimicrobial Activities ◽  
Curvularia Lunata ◽  
Root Bark ◽  
Inhibitory Activities ◽  
Alkaloid Extracts

Background and Aims: The phytochemistry study of Annonaceae has intensified in the last decades due to the discovery of secondary metabolites with antimicrobial activities. The inhibitory activities of extracts and compounds from these species for phytopathogens are less known. The antifungal activity of Sapranthus microcarpus was determined in vitro against six fungal pathogens of important crops.Methods: Hexane, methanol, and alkaloid extracts of the leaves and root and stem bark of S. microcarpus were evaluated to determine whether they could inhibit the mycelial growth of the phytopathogens. The combined activity of the most active extracts for each phytopathogen was also determined. The alkaloid liriodenine was isolated and identified as an antifungal principle.Key results: All extracts inhibited the growth of the six phytopathogens to some extent. The root bark alkaloid extract showed the highest activity. Fusarium oxysporum f. sp. lycopersici and Curvularia lunata were the most sensitive phytopathogens. Liriodenine was active against all the plant pathogens (minimum inhibitory concentrations of 125-500 nmol ml-1).Conclusions: Sapranthus microcarpus is a native natural resource with great phytochemical potential.

scholarly journals Antifungal activity of saponins originated from Medicago hybrida against some ornamental plant pathogens

2012 ◽  
Vol 59 (2) ◽  
pp. 51-58 ◽  
Author(s):  
Alicja Saniewska ◽  
Anna Jarecka ◽  
Zbigniew Biały ◽  
Marian Jurzysta
Keyword(s):  
Antifungal Activity ◽  
Fusarium Oxysporum ◽  
Botrytis Cinerea ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Ornamental Plant ◽  
Mycelium Growth ◽  
Medicagenic Acid ◽  
Fungitoxic Effect

Antifungal activity of total saponins originated from roots of <i>Medicago hybrida</i> (Pourret) Trautv. were evaluated <i>in vitro</i> against six pathogenic fungi and eight individual major saponin glycosides were tested against one of the most susceptible fungi. The total saponins showed fungitoxic effect at all investigated concentrations (0.01%, 0.05% and 0.1%) but their potency was different for individual fungi. The highest saponin concentration (0.1%) was the most effective and the inhibition of <i>Fusarium oxysporum</i> f. sp. <i>callistephi</i>, <i>Botrytis cinerea</i>, <i>Botrytis tulipae</i>, <i>Phoma narcissi</i>, <i>Fusarium oxysporum</i> f. sp. <i>narcissi</i> was 84.4%, 69.9%, 68.6%, 57.2%, 55.0%, respectively. While <i>Fusarium oxysporum</i> Schlecht., a pathogen of <i>Muscari armeniacum</i>, was inhibited by 9.5% only. Eight major saponin glycosides isolated from the total saponins of <i>M. hybrida</i> roots were tested against the mycelium growth of <i>Botrytis tulipae</i>. The mycelium growth of the pathogen was greatly inhibited by hederagenin 3-O-<i>β</i>-D-glucopyranoside and medicagenic acid 3-O-<i>β</i>-D-glucopyranoside. Medicagenic acid 3-O-<i>β</i>-D-glucuronopyranosyl-28-O-<i>β</i>-D-glucopyranoside and oleanolic acid 3-O-[<i>β</i>-D-glucuronopyranosyl(1→2)-<i>α</i>-L-galactopyranosyl]-28-O-<i>β</i>-D-glucopyranoside showed low fungitoxic activity. Medicagenic acid 3-O-a-D-glucopyranosyl- 28-O-β-D-glucopyranoside, hederagenin 3-O-[α-L- hamnopyranosyl(1→2)-β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]- 28-O-α-D-glucopyranoside and hederagenin 3-O-<i>β</i>-D-glucuronopyranosyl-28-O-<i>β</i>-D- lucopyranoside did not limit or only slightly inhibited growth of the tested pathogen. While 2<i>β</i>, 3<i>β</i>-dihydroxyolean-12 ene-23-al-28-oic acid 3-O-<i>β</i>-D-glucuronopyranosyl-28-O-<i>β</i>-D-glucopyranoside slightly stimulated mycelium growth of <i>B. tulipae</i>.

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