The Potential of New Streptomyces Isolates as Biocontrol Agents Against Fusarium Spp

Abstract The excessive use of synthetic pesticides for plant pathogens control could cause possible harmful side-effects to humans and animals, environmental pollution, residual toxicity, affects soil characteristics or induce the development of fungal resistance. Alternative ways for fungal contamination control involve natural products, based on microorganisms, many of them being already available for use. The selection and characterization of new biological agents useful for plant pathogens control are permanent goals for plant protection researches. In the last decade, several studies revealed that Streptomyces species are promising biocontrol agents against a wide range of phytopathogenic fungi, including Fusarium spp., one of the most important wheat pathogens. In our study, 60 strains of Streptomyces spp. were isolated from soil or compost and evaluated for in vitro antifungal abilities by dual confrontation method. At least 30% of the isolates presented inhibitory activity against F. culmorum and F. graminearum. The bacterial strains were also tested for their ability to produce various bioactive compounds, possible involved in fungal inhibition. The capacity of some of the bacterial isolates to produce cellulases, amylases, lipases and volatile metabolites was proved. In addition, a new screening method for chitinases production was developed, based on the use of a combination of Congo red and Lugol solutions, which allowed the detection of chitinases in several Streptomyces spp. strains. Moreover, the reduction of the level of some Fusarium mycotoxins was detected by HPTLC analysis. As a conclusion, antagonistic interactions between Streptomyces isolates and fusaria could involve antibiosis, competition and parasitism and suggested that at least some of the selected isolates could be used in obtaining biological control products.

Download Full-text

In vitro Insecticidal and Time-Kill Profile of Ethyl Acetate Extract of Marine Streptomyces sp. Isolated from Sundarbans, Bangladesh

Bangladesh Pharmaceutical Journal ◽

10.3329/bpj.v17i2.22332 ◽

2015 ◽

Vol 17 (2) ◽

pp. 151-156 ◽

Cited By ~ 1

Author(s):

Md Anwarul Haque ◽

Ashish Kumar Sarker ◽

Mohammad Sayful Islam ◽

Md Ajijur Rahman ◽

Md Akter Uzzaman Chouduri ◽

...

Keyword(s):

Ethyl Acetate ◽

Mangrove Forest ◽

Bacterial Strains ◽

Streptomyces Species ◽

Streptomyces Sp ◽

Cell Counts ◽

Wide Range ◽

Marine Streptomyces ◽

Time Kill

The marine soil and sediment samples were collected from different locations of mangrove forest Sundarbans, Bangladesh the largest tidal halophytic mangrove forest in the world. A total of twenty nine Actinomycete strains (AIAH-1 to AIAH-29) were isolated by serial dilution method using isolation media. Among twenty nine strains, AIAH-10 was selected for further study due to its potent antibacterial activity against a wide range of pathogenic bacterial strains. On the basis of morphological, cultural and biochemical studies, the strain AIAH-10 was assigned to Streptomyces sp. The present study was designed to investigate the in vitro insecticidal and time-kill profile of ethyl acetate extracts of marine Streptomyces sp. A dose dependent mortality was observed against the larvae of Sitophilus oryzae. The larval mortality was recorded as 100% in the concentration of 80 mg/ml and higher concentrations, LC50 was found as 11.48 mg/ml. The minimum inhibitory concentration was recorded as 8 to 32 mg/ml against six different pathogenic bacterial strains. Average Log10 reductions in viable cell counts for the extracts ranged from 1.91 Log10 and 2.86 Log10 cfu/mL after 3 h interaction and 2.10 Log10 and 2.93 Log10 after 6 h interaction at MIC, 2 × MIC, 3 × MIC and 4 × MIC concentrations. This investigation reveals that the Streptomyces species isolated from Sundarbans, Bangladesh may be interesting source for the isolation of potent bioactive compounds. DOI: http://dx.doi.org/10.3329/bpj.v17i2.22332 Bangladesh Pharmaceutical Journal 17(2): 151-156, 2014

Download Full-text

The Significance of Bacillus spp. in Disease Suppression and Growth Promotion of Field and Vegetable Crops

Microorganisms ◽

10.3390/microorganisms8071037 ◽

2020 ◽

Vol 8 (7) ◽

pp. 1037 ◽

Cited By ~ 1

Author(s):

Dragana Miljaković ◽

Jelena Marinković ◽

Svetlana Balešević-Tubić

Keyword(s):

Plant Growth ◽

Plant Pathogens ◽

Growth Promotion ◽

Disease Suppression ◽

Biocontrol Agents ◽

Systemic Resistance ◽

Steady Increase ◽

Vegetable Crops ◽

Wide Range ◽

Bacillus Spp

Bacillus spp. produce a variety of compounds involved in the biocontrol of plant pathogens and promotion of plant growth, which makes them potential candidates for most agricultural and biotechnological applications. Bacilli exhibit antagonistic activity by excreting extracellular metabolites such as antibiotics, cell wall hydrolases, and siderophores. Additionally, Bacillus spp. improve plant response to pathogen attack by triggering induced systemic resistance (ISR). Besides being the most promising biocontrol agents, Bacillus spp. promote plant growth via nitrogen fixation, phosphate solubilization, and phytohormone production. Antagonistic and plant growth-promoting strains of Bacillus spp. might be useful in formulating new preparations. Numerous studies of a wide range of plant species revealed a steady increase in the number of Bacillus spp. identified as potential biocontrol agents and plant growth promoters. Among different mechanisms of action, it remains unclear which individual or combined traits could be used as predictors in the selection of the best strains for crop productivity improvement. Due to numerous factors that influence the successful application of Bacillus spp., it is necessary to understand how different strains function in biological control and plant growth promotion, and distinctly define the factors that contribute to their more efficient use in the field.

Download Full-text

Morphological and molecular based identification of Antifungal bacillus licheniformis

Mongolian Journal of Agricultural Sciences ◽

10.5564/mjas.v17i1.724 ◽

2017 ◽

Vol 17 (1) ◽

pp. 31-35

Author(s):

B Oyuntogtokh ◽

M Byambasuren

Keyword(s):

Bacillus Licheniformis ◽

Fungal Pathogens ◽

Crop Production ◽

Plant Pathogens ◽

Control Plant ◽

Plant Diseases ◽

Bacillus Species ◽

Bacterial Strains ◽

Fusarium Spp ◽

Bacterial Cultures

At present, plant diseases caused by soil borne plant pathogens have major constraints on crop production. Which include genera Fusarium spp, Phytophtora spp, Sclerotinia and Altenaria. Due to this reason, chemical fungicides are routinely used to control plant disease, which is also true in Mongolian case. However, use of these chemicals has caused various problems including environmental pollution with consequence of toxicity to human health also resistance of some pathogens to these fungicides are present. Fortunately, an alternative method to reduce the effect of these plant pathogens is the use of antagonist microorganisms. Therefore, some species of the genus Bacillus are recognized as one of the most effective biological control agent.Our research was focused to isolate Bacillus licheniformis, with antifungal potential, from indigenous sources. In the current study, 28 bacterial cultures were isolated from soil and fermented mare’s milk also named as koumiss. Isolated bacterial cultures were identified according to simplified key for the tentative identification of typical strain of Bacillus species. As a result 8 strains were positive and further screened for antifungal activity against Fusarium spp and Alternaria solani. Out of these 8 strains 5 strains are selected based on their high effectiveness against fungal pathogens and for further confirmation Polymerase Chain reaction run for effective bacterial strains using specific primers B.Lich-f and B.Lich-r.

Download Full-text

De Novo Design of Antimicrobial Peptides With a Special Charge Pattern and Their Application in Combating Plant Pathogens

Frontiers in Plant Science ◽

10.3389/fpls.2021.753217 ◽

2021 ◽

Vol 12 ◽

Author(s):

Eric H. -L. Chen ◽

Cheng-Wei Weng ◽

Yi-Min Li ◽

Ming-Chin Wu ◽

Chien-Chih Yang ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Peptides ◽

Plant Pathogens ◽

De Novo ◽

Plant Protection ◽

Acyl Chain ◽

Fatty Acyl ◽

Plant Diseases ◽

Basic Residue ◽

Wide Range

Plant diseases are important issues in agriculture, and the development of effective and environment-friendly means of disease control is crucial and highly desired. Antimicrobial peptides (AMPs) are known as potential alternatives to chemical pesticides because of their potent broad-spectrum antimicrobial activity and because they have no risk, or have only a low risk, of developing chemical-resistant pathogens. In this study, we designed a series of amphipathic helical peptides with different spatial distributions of positive charges and found that the peptides that had a special sequence pattern “BBHBBHHBBH” (“B” for basic residue and “H” for hydrophobic residue) displayed excellent bactericidal and fungicidal activities in a wide range of economically important plant pathogens. The peptides with higher helical propensity had lower antimicrobial activity. When we modified the peptides with a long acyl chain at their N-terminus, their plant protection effect improved. Our application of the fatty acyl-modified peptides on the leaves of tomato and Arabidopsis plants lessened the infection caused by Pectobacterium carotovorum subsp. carotovorum and Botrytis cinerea. Our study provides important insights on the development of more potent novel AMPs for plant protection.

Download Full-text

Screening of the High-Rhizosphere Competent Limoniastrum monopetalum’ Culturable Endophyte Microbiota Allows the Recovery of Multifaceted and Versatile Biocontrol Agents

Microorganisms ◽

10.3390/microorganisms7080249 ◽

2019 ◽

Vol 7 (8) ◽

pp. 249 ◽

Cited By ~ 4

Author(s):

Houda Ben Slama ◽

Mohamed Ali Triki ◽

Ali Chenari Bouket ◽

Fedia Ben Mefteh ◽

Faizah N. Alenezi ◽

...

Keyword(s):

Plant Growth ◽

Abiotic Stresses ◽

Plant Pathogens ◽

Metal Removal ◽

Plant Protection ◽

Biocontrol Agents ◽

In Planta ◽

Olive Trees ◽

Limoniastrum Monopetalum ◽

Selection Of

Halophyte Limoniastrum monopetalum, an evergreen shrub inhabiting the Mediterranean region, has well-documented phytoremediation potential for metal removal from polluted sites. It is also considered to be a medicinal halophyte with potent activity against plant pathogens. Therefore, L. monopetalum may be a suitable candidate for isolating endophytic microbiota members that provide plant growth promotion (PGP) and resistance to abiotic stresses. Selected for biocontrol abilities, these endophytes may represent multifaceted and versatile biocontrol agents, combining pathogen biocontrol in addition to PGP and plant protection against abiotic stresses. In this study 117 root culturable bacterial endophytes, including Gram-positive (Bacillus and Brevibacillus), Gram-negative (Proteus, Providencia, Serratia, Pantoea, Klebsiella, Enterobacter and Pectobacterium) and actinomycete Nocardiopsis genera have been recovered from L. monopetalum. The collection exhibited high levels of biocontrol abilities against bacterial (Agrobacterium tumefaciens MAT2 and Pectobacterium carotovorum MAT3) and fungal (Alternaria alternata XSZJY-1, Rhizoctonia bataticola MAT1 and Fusarium oxysporum f. sp. radicis lycopersici FORL) pathogens. Several bacteria also showed PGP capacity and resistance to antibiotics and metals. A highly promising candidate Bacillus licheniformis LMRE 36 with high PGP, biocontrol, metal and antibiotic, resistance was subsequently tested in planta (potato and olive trees) for biocontrol of a collection of 14 highly damaging Fusarium species. LMRE 36 proved very effective against the collection in both species and against an emerging Fusarium sp. threatening olive trees culture in nurseries. These findings provide a demonstration of our pyramiding strategy. Our strategy was effective in combining desirable traits in biocontrol agents towards broad-spectrum resistance against pathogens and protection of crops from abiotic stresses. Stacking multiple desirable traits into a single biocontrol agent is achieved by first, careful selection of a host for endophytic microbiota recovery; second, stringent in vitro selection of candidates from the collection; and third, application of the selected biocontrol agents in planta experiments. That pyramiding strategy could be successfully used to mitigate effects of diverse biotic and abiotic stresses on plant growth and productivity. It is anticipated that the strategy will provide a new generation of biocontrol agents by targeting the microbiota of plants in hostile environments.

Download Full-text

Morphological and molecular characterisation of Streptomyces spp. which suppress pathogenic fungi

African Crop Science Journal ◽

10.4314/acsj.v28i4.6 ◽

2020 ◽

Vol 28 (4) ◽

pp. 555-566

Author(s):

N. Goredema ◽

T. Ndowora ◽

R. Shoko ◽

E. Ngadze

Keyword(s):

Antimicrobial Activity ◽

Fusarium Oxysporum ◽

Aspergillus Flavus ◽

Plant Pathogens ◽

Morphological Characteristics ◽

Molecular Characteristics ◽

Penicillium Italicum ◽

Streptomyces Species ◽

Genus Streptomyces ◽

Wide Range

Streptomyces species are aerobes and chemoorganotrophic bacteria. These microorganisms produce a wide range of industrially significant compounds, specifically antibiotics and anti fungal substances. The objective of this study was to characterise soil-borne Streptomyces isolates using morphological and molecular traits in order to identify them to species level, and leverage from their potential to suppress the growth of Aspergillus flavus, Fusarium oxysporum and Penicillium italicum. Twenty-seven soil-borne putative Streptomyces, which elicited comprehensive antimicrobial activity against Aspergillus flavus, Fusarium oxysporum and Penicillium italicum, in a previous study, were evaluated. On the basis of morphology, the bacteria resembled the genus Streptomyces. Initially, colonies phenotypically appeared to have a relatively smooth surface but as growth progressed the bacteria developed a weft of aerial mycelium granular, powdery or velvety in appearance. Bacteria produced a wide variety of pigments which in turn were responsible for the colour of the vegetative and aerial mycelia, colour ranged from white to cream or buff shades and yellow to orange or brown. Microscopic analyses and morphological characteristics generated sub-groups of the isolates and clustered them according to their similarities. One bacterial strain was randomly selected from each cluster and investigated using molecular characteristics. Partial 16S rDNAs from the selected representative isolates from each subgroup, were sequenced and phylogenetic analysis performed. The 16S rDNA sequences of the isolates indicated that they were related to Streptomyces species: S. bungoensis, S. thermocarboxydus, S. corchorusii and S. lasaliensis, that are known secondary metabolite producers possessing antimicrobial activity against plant pathogens.

Download Full-text

Exploration of The Biocontrol Potential of Halophilic Bacteria Against Sclerotium Oryzae and Rhizoctonia Solani

10.21203/rs.3.rs-171299/v1 ◽

2021 ◽

Author(s):

Yalavarthi Nagaraju ◽

Mahadeva swamy ◽

R.C. Gundappagol ◽

Nagaraj M Naik ◽

K. Narayana Rao

Keyword(s):

Plant Pathogens ◽

Halophilic Bacteria ◽

Hydrolytic Enzymes ◽

Pseudomonas Stutzeri ◽

Culture Method ◽

Biocontrol Agents ◽

Dual Culture ◽

Bacterial Strains ◽

16S Rrna Analysis

Abstract There is a pressing need for biocontrol agents to control soil borne plant pathogens through biocontrol agents. The focus of this research was on the interactions of halophilic bacterial isolates with the phytopathogenic fungi such as Sclerotium oryzae and R. solanii. The biocontrol ability of fifty bacterial strains isolated from saline soils of the Koppal (Gangavathi) and Raichur districts was assessed in vitro. Eight isolates, HB-10, HB-17, HB-28, HB-30, HB-39, HB-48, HB-49 and HB-50 showed strong antifungal activity against S. oryzae and R. solani in dual culture method. These prospective isolates were identified as Bacillus cereus (HB-48 and HB-49), Bacillus albus (HB-17), Bacillus safensis (HB-28), Staphylococcus xylosus (HB-39), Lysinibacillus sphaericus (HB-50) and Pseudomonas stutzeri (HB-10 and HB-30) based on 16S rRNA analysis. We found a link between isolates producing HCN, siderophore and hydrolytic enzymes and the biocontrol function of isolates. The isolate B. albus (HB-17), produced both catechol and hydroximate type of siderophores, confirmed in Arnow’s and Csaky’s tests. All isolates were tested for drug resistance and were shown to be immune to penicillin, oflaxacin and vancomycin. In addition, these isolates were investigated at three NaCl concentrations (3, 6 and 10 % w/v) for their plant growth promoting attributes viz., phosphorous, and zinc solubilization and potassium release. The solubilization zones of zinc carbonate, zinc oxide and phosphorous were within the range of 5.20 to 9.0 mm, 6.06 to 13.20 mm, 6.30 to 9.70 mm respectively, at 6 % NaCl concentration.

Download Full-text

Biostimulation of Bacteria in Liquid Culture for Identification of New Antimicrobial Compounds

Pharmaceuticals ◽

10.3390/ph14121232 ◽

2021 ◽

Vol 14 (12) ◽

pp. 1232

Author(s):

Hooman Mirzaee ◽

Emily Ariens ◽

Mark A. T. Blaskovich ◽

Richard J. Clark ◽

Peer M. Schenk

Keyword(s):

Bioactive Compounds ◽

Ribosomal Proteins ◽

Liquid Culture ◽

Plant Pathogens ◽

Antimicrobial Compounds ◽

Bacterial Strains ◽

Microbial Inhibition ◽

Wide Range ◽

Shock Proteins ◽

Bacterial Supernatants

We hypothesized that environmental microbiomes contain a wide range of bacteria that produce yet uncharacterized antimicrobial compounds (AMCs) that can potentially be used to control pathogens. Over 600 bacterial strains were isolated from soil and food compost samples, and 68 biocontrol bacteria with antimicrobial activity were chosen for further studies based on inhibition assays against a wide range of food and plant pathogens. For further characterization of the bioactive compounds, a new method was established that used living pathogens in a liquid culture to stimulate bacteria to produce high amounts of AMCs in bacterial supernatants. A peptide gel electrophoresis microbial inhibition assay was used to concurrently achieve size separation of the antimicrobial peptides. Fifteen potential bioactive peptides were then further characterized by tandem MS, revealing cold-shock proteins and 50S ribosomal proteins. To identify non-peptidic AMCs, bacterial supernatants were analyzed by HPLC followed by GC/MS. Among the 14 identified bioactive compounds, 3-isobutylhexahydropyrrolo[1,2-a]pyrazine-1,4-dione and 2-acetyl-3-methyl-octahydropyrrolo[1,2-a]piperazine-1,4-dione were identified as new AMCs. Our work suggests that antimicrobial compound production in microbes is enhanced when faced with a threat from other microorganisms, and that this approach can rapidly lead to the development of new antimicrobials with the potential for upscaling.

Download Full-text

Exploring Two Streptomyces Species to Control Rhizoctonia solani in Tomato

Agronomy ◽

10.3390/agronomy11071384 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1384

Author(s):

Marzieh Ebrahimi-Zarandi ◽

Gholam Hosein Shahidi Bonjar ◽

Roohallah Saberi Riseh ◽

Mohamed El-Shetehy ◽

Ismail Saadoun ◽

...

Keyword(s):

Plant Growth ◽

Rhizoctonia Solani ◽

Plant Pathogens ◽

Biochemical Characterization ◽

Induced Defense ◽

Biocontrol Agents ◽

Tomato Root ◽

Streptomyces Species ◽

Tomato Plants ◽

Phenyl Propanoid

Streptomyces species are effective biocontrol agents toward many plant pathogens. These microorganisms are well known for producing secondary metabolites, promoting plant growth and inducing plant defense mechanisms. In this study, the ability of tomato root-colonizing Streptomyces strains to trigger the resistance against Rhizoctonia solani (J.G. Kühn) AG4 was investigated. For this goal, we evaluated the pattern of LOXB and PAL1 genes expression changes upon pathogen inoculation in primed tomato plants. The results revealed that Streptomyces globisporous (Krasil'nikov) strain F8 and S. praecox (Millard and Burr) strain R7 were able to enhance the expression of lipoxygenase and phenylalanine ammonia lyase in tomato plants. This finding suggests that Streptomyces strains F8 and R7 may trigger jasmonic acid and phenyl propanoid signaling pathways in plants, therefore, resulting an induced defense status in tomatoes against R. solani. Biochemical characterization of these Streptomyces strains showed that they were strong producers of siderophores. S. praecox strain R7 produced siderophores of hyderoxamate and catechol types and S. globisporous strain F8 produced a phenolic siderophore. Moreover, they also produced protease while only the S. praecox strain R7 was able to produce amylase. Taken together, these results indicate that S. globisporous strain F8 and S. praecox strain R7 promote plant growth and reduces disease and hence are suitable for future in depth and field studies with the aim to attain appropriate biocontrol agents to protect tomatoes against R. solani.

Download Full-text

Ecological Dynamics and Microbial Treatments against Oomycete Plant Pathogens

Plants ◽

10.3390/plants10122697 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2697

Author(s):

Karen E. Sullam ◽

Tomke Musa

Keyword(s):

Plant Pathogens ◽

Plant Protection ◽

Ecological Factors ◽

Plant Protection Products ◽

Biocontrol Agents ◽

Economic Damage ◽

Ecological Processes ◽

Environmental Interactions ◽

Ecological Concepts ◽

Microbial Biocontrol Agents

In this review, we explore how ecological concepts may help assist with applying microbial biocontrol agents to oomycete pathogens. Oomycetes cause a variety of agricultural diseases, including potato late blight, apple replant diseases, and downy mildew of grapevine, which also can lead to significant economic damage in their respective crops. The use of microbial biocontrol agents is increasingly gaining interest due to pressure from governments and society to reduce chemical plant protection products. The success of a biocontrol agent is dependent on many ecological processes, including the establishment on the host, persistence in the environment, and expression of traits that may be dependent on the microbiome. This review examines recent literature and trends in research that incorporate ecological aspects, especially microbiome, host, and environmental interactions, into biological control development and applications. We explore ecological factors that may influence microbial biocontrol agents’ efficacy and discuss key research avenues forward.

Download Full-text