scholarly journals Growth Inhibition of Fungal Plant Pathogens by Antagonist Bacteria Using Dual Culture Assays

BIOTROPIA ◽  
2021 ◽  
Vol 28 (3) ◽  
Keyword(s):  
Growth Inhibition ◽  
Plant Pathogens ◽  
Dual Culture ◽  
Fungal Plant Pathogens

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 Biological Control Potential of Streptomyces sp. AR10 Producing Albocycline Isolated from Soil around Ant Nest

2018 ◽  
Vol 10 (3) ◽  
pp. 54
Author(s):  
Tatsuya Ohike ◽  
Tetsuya Matsukawa ◽  
Masahiro Okanami ◽  
Shin’ichiro Kajiyama ◽  
Takashi Ano
Keyword(s):  
Biological Control ◽  
Plant Pathogens ◽  
Sequence Similarity ◽  
Antifungal Compound ◽  
Dual Culture ◽  
High Sequence Similarity ◽  
Genus Streptomyces ◽  
Fungal Plant Pathogens ◽  
Biological Control Potential ◽  
Dual Culture Assay

Fifty actinomycetes were isolated from fifteen soil samples and were screened for their antagonism against fungal plant pathogens by dual culture assay, and one of the strain named AR10 was shown to be most effective in suppression of growth of plant pathogen. An antifungal compound of AR10 was extracted, and purified by TLC and HPLC. As a result of NMR and LC-MS analysis, the antifungal compound was identified as albocycline. AR10 suppressed Rhizoctonia damping-off of cucumber in infection control assay. The 16S rDNA sequence of AR10 shows high sequence similarity to those of genus Streptomyces, and the closest similarity was found in the sequence of S. lanatus NBRC 12787T with 98.7% similarity. However, the production of albocycline in Streptomyces closely related to AR10 in the phylogenetic tree has not been reported. Our finding suggests that AR10 can be a candidate for biological control agents.

scholarly journals Diversity of biocontrol agents, isolated from several sources, inhibitory to several fungal plant pathogens

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Yan Ramona ◽  
IDA BAGUS GEDE DARMAYASA ◽  
ANAK AGUNG NGURAH NARA KUSUMA ◽  
Martin Line
Keyword(s):  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Antagonistic Activity ◽  
Significant Inhibition ◽  
Biocontrol Agents ◽  
Dual Culture ◽  
Rdna Sequences ◽  
Fungal Plant Pathogens ◽  
Mature Compost

Abstract. Ramona Y, Darmayasa IBG, Kusuma AANN, Line MA. 2021. Diversity of biocontrol agents, isolated from several sources, inhibitory to several fungal plant pathogens. Biodiversitas 22: 298-303. This study investigated the inhibitory potential of diversity of antagonist bacteria residing in the rhizosphere zone and mature compost to counter fungal plant pathogens. Soils collected from rhizosphere of lettuce farms in Bali-Indonesia and Tasmania-Australia, mature compost, commercial biocontrol (Dipel®), and laboratory contaminants with significant inhibition against tested fungal pathogens were used as sources of antagonist bacteria. These antagonists were isolated by applying dilution and spread method on trypticase soya agar (TSA) or potato dextrose agar (PDA), and their ability to inhibit Sclerotinia minor, Sclerotinia sclerotiorum, Fusarium spp., and Rhizoctonia solani was assessed in dual culture assays. The results showed that 67 out of more than 100 isolates had antagonistic activity in vitro against at least one of tested fungal pathogens. In the preliminary identification, Bacillus spp. or Pseudomonas spp. were found to be pre-dominant isolates. Following screening studies in a non-replicated glasshouse experiment against S. minor and S. sclerotiorum, 8 of the most promising isolates were further identified using molecular methods based on their 16s rDNA sequences aligned with those deposited at the GeneBank. These 8 isolates were identified as Pseudomonas corrugata, Bacillus megaterium, Bacillus polymyxa, Bacillus mojavensis, Bacillus pumilus, Bacillus thuringiensis, Exiguobacterium acetylicum, and Chryseobacterium indologenes.

scholarly journals Growth-inhibiting activity of citronella essential oil to multiple fungal plant pathogens

2019 ◽  
Author(s):  
Mark Angelo O. Balendres ◽  
Fe M. Dela Cueva
Keyword(s):  
Essential Oil ◽  
Growth Inhibition ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Germ Tube ◽  
Plant Pathogens ◽  
Field Experiments ◽  
Fungal Plant Pathogens ◽  
Germ Tube Elongation

AbstractCymbopogon species are among the most reported essential oils with fungitoxic effect. In this study, mycelial growth of Fusarium oxysporum (banana wilt), Colletotrichum gloeosporioides (mango anthracnose), C. falcatum (sugarcane red rot) and Neopestalotiopsis spp. (mango leaf spot) as influenced by varying concentrations of citronella essential oil (CEO) was assessed in in vitro assays. Following growth inhibition test, spore germination and germ tube elongation of C. gloeosporioides were then examined. Mycelial growth of all test fungal pathogens was strongly inhibited by CEO, but variations were observed among fungal species. This growth inhibition activity was caused by the inhibition of spore germination and germ tube elongation as observed in C. gloeosporioides. The findings of this study show the strong growth-inhibitory activity of CEO to multiple fungal pathogens, indicating CEO’s potential as a chemical control approach against these fungal pathogens. Glasshouse and field experiments would establish CEO as one potential alternative to fungicides.

Characterization of Volatile Constituents from Origanum onites and Their Antifungal and Antibacterial Activity

2013 ◽  
Vol 96 (6) ◽  
pp. 1200-1208 ◽  
Author(s):  
Ayhan Altintas ◽  
Nurhayat Tabanca ◽  
Erno Tyihák ◽  
Péter G Ott ◽  
Ágnes M Móricz ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antifungal Activity ◽  
Growth Inhibition ◽  
Essential Oils ◽  
Plant Pathogens ◽  
Colletotrichum Acutatum ◽  
Reaction Products ◽  
Colletotrichum Species ◽  
Fungal Plant Pathogens ◽  
Origanum Onites

Abstract Essential oils obtained by hydrodistillation (HD) and microwave-assisted HD (MWHD) of Origanum onites aerial parts were analyzed by GC and GC/MS. Thirty-one constituents representing 98.6% of the water-distilled oil and 52 constituents representing 99.6% of the microwave-distilled oil were identified. Carvacrol (76.8% HD and 79.2% MWHD) and thymol (4.7% HD and 4.4% MWHD) were characterized as major constituents in both essential oils. Separation of carvacrol and thymol was achieved by overpressured layer chromatography. HPTLC and TLC separations were also compared. Essential oils were evaluated for antifungal activity against the strawberry anthracnose-causing fungal plant pathogens Colletotrichum acutatum, C. fragariae, and C. gloeosporioides using a direct overlay bioautography assay. Furthermore, main oil components carvacrol and thymol were then evaluated for antifungal activity; only carvacrol demonstrated nonselective antifungal activity against the three Colletotrichum species. Thymol and carvacrol were subsequently evaluated in a 96-well microdilution broth assay against Phomopsis obscurans, Fusarium oxysporum, three Colletotrichum species, and Botrytis cinerea. No activity was observed against any of the three Colletotrichum species at or below 30 μM. However, thymol demonstrated antifungal activity and produced 31.7% growth inhibition of P. obscurans at 120 h and 0.3 μM, whereas carvacrol appeared inactive. Thymol and carvacrol at 30 μM showed 51.5 and 36.9% growth inhibition of B. cinerea at 72 h. The mechanism of antibacterial activity was studied in a bioautography-based BioArena system. Thymol and carvacrol showed similar inhibition/killing effect against Bacillus subtilis soil bacteria; the action could be enhanced by the formaldehyde generator and transporter copper(II) ions and could be decreased in the presence of L-arginine, a formaldehyde capturer. Results indicated that Origanum essential oils and its major components thymol and carvacrol appear to generate antimicrobial activity through a mechanism of action where formaldehyde and its reaction products are produced.

scholarly journals In-vitro Evaluation of Actinobacteria for its Potential in Bio-control of Fungal Plant Pathogens

2019 ◽  
Vol 7 (1) ◽  
pp. 82-87
Author(s):  
Zothan puia ◽  
◽  
W. Carrie ◽  
V.V. Leo ◽  
A.K. Passari ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Control Strategies ◽  
Dual Culture ◽  
Inhibition Activity ◽  
Fungal Plant Pathogens ◽  
Basic Understanding ◽  
Dual Culture Assay ◽  
Antagonistic Potential ◽  
Fungal Phytopathogens

Infections caused by fungal plant pathogens are recently recognized as a threat to food security worldwide and its control strategies need to be taken care where naturally synthesized fungicides such as those obtained from actinobacteria are becoming an area of great interest. A total of 68 isolates of actinobacteria were evaluated for their antagonistic potential against four fungal plant pathogens viz., Fusarium oxysporum CABI-293942, Fusarium udum MTCC-2755, Fusarium proliferatum MTCC-286 and Fusarium graminearum MTCC-1893 by dual culture assay. It was found that 83.8% of the isolates showed inhibitory activity against at least one of the tested plant pathogens with the percentage of inhibition ranging from 20–87.2. Thirteen Streptomyces isolates and one Nocardiposis isolate exhibited inhibition activity against all the tested pathogens. Overall, this study gives a basic understanding of the potential aspect of freshwater sediments derived actinobacteria against fungal phytopathogens.

scholarly journals Antifungal Activity of Bioactive Metabolites Produced by Trichoderma asperellum and Trichoderma atroviride in Liquid Medium

2020 ◽  
Vol 6 (4) ◽  
pp. 263
Author(s):  
Claudia Stracquadanio ◽  
Juan Manuel Quiles ◽  
Giuseppe Meca ◽  
Santa Olga Cacciola
Keyword(s):  
Organic Compounds ◽  
Direct Contact ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Antimicrobial Activities ◽  
Bioactive Metabolites ◽  
Dual Culture ◽  
Trichoderma Spp ◽  
Minimum Fungicidal Concentration ◽  
Fungal Plant Pathogens

Trichoderma spp. are known as biocontrol agents of fungal plant pathogens and have been recognized as a potential source of bioactive metabolites. The production of antimicrobial substances from strains T. atroviride (TS) and T. asperellum (IMI 393899) was investigated. The bioactivity of 10- and 30-day culture filtrate extracted with ethyl acetate was assessed against a set of pathogenic fungi and oomycetes. The 30-day extracts of both strains had significant cytotoxic effects against the tested pathogens, with values of minimum fungicidal concentration (MFC) ranging between 0.19 and 6.25 mg/mL. Dual culture assay (direct contact and nondirect contact) and the percentage inhibition of radial growth (PIRG) was calculated. The highest PIRG values were 76% and 81% (direct contact) with IMI 393899 and TS, respectively. Nondirect contact does not show inhibition on any of pathogens tested, indicating that the inhibition is not due to the secretion of volatile substances. Culture filtrates were analyzed by GC-MS and HPLC-Q-TOF-MS for the identification of volatile organic compounds (VOCs) and nonvolatile organic compounds (nVOCs), respectively. Seven classes of VOCs and 12 molecules of nVOCs were identified. These results indicate that these strains of Trichoderma had antimicrobial activities and they are potential natural sources of compounds with biological activity.

Morphological, biochemical and molecular identification of rhizobacteria isolates with potential for biocontrol of fungal plant pathogens

2021 ◽  
pp. 1-14
Author(s):  
Stephen Larbi-Koranteng ◽  
Richard Tuyee Awuah ◽  
Fredrick Kankam ◽  
Muntala Abdulai ◽  
Marian Dorcas Quain ◽  
...  
Keyword(s):  
Molecular Identification ◽  
Plant Pathogens ◽  
Fungal Plant Pathogens

scholarly journals The carbon source-dependent pattern of antimicrobial activity and gene expression in Pseudomonas donghuensis P482

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Matuszewska ◽  
Tomasz Maciąg ◽  
Magdalena Rajewska ◽  
Aldona Wierzbicka ◽  
Sylwia Jafra
Keyword(s):  
Gene Expression ◽  
Antimicrobial Activity ◽  
Carbon Source ◽  
Reference Genes ◽  
Plant Pathogens ◽  
Plant Protection ◽  
Carbon Sources ◽  
Unknown Compound ◽  
Fungal Plant Pathogens ◽  
The Impact

AbstractPseudomonas donghuensis P482 is a tomato rhizosphere isolate with the ability to inhibit growth of bacterial and fungal plant pathogens. Herein, we analysed the impact of the carbon source on the antibacterial activity of P482 and expression of the selected genes of three genomic regions in the P482 genome. These regions are involved in the synthesis of pyoverdine, 7-hydroxytropolone (7-HT) and an unknown compound (“cluster 17”) and are responsible for the antimicrobial activity of P482. We showed that the P482 mutants, defective in these regions, show variations and contrasting patterns of growth inhibition of the target pathogen under given nutritional conditions (with glucose or glycerol as a carbon source). We also selected and validated the reference genes for gene expression studies in P. donghuensis P482. Amongst ten candidate genes, we found gyrB, rpoD and mrdA the most stably expressed. Using selected reference genes in RT-qPCR, we assessed the expression of the genes of interest under minimal medium conditions with glucose or glycerol as carbon sources. Glycerol was shown to negatively affect the expression of genes necessary for 7-HT synthesis. The significance of this finding in the light of the role of nutrient (carbon) availability in biological plant protection is discussed.

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