scholarly journals Exploring Two Streptomyces Species to Control Rhizoctonia solani in Tomato

Agronomy ◽  
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.

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

2020 ◽  
Vol 8 (7) ◽  
pp. 1037 ◽  
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.

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

2018 ◽  
Vol 1 (1) ◽  
pp. 594-600
Author(s):  
Mihaela Ursan ◽  
Oana Alina Boiu-Sicuia ◽  
Cătălina Voaides ◽  
Vasilica Stan ◽  
Corina Bubueanu ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Plant Protection ◽  
Screening Method ◽  
Biocontrol Agents ◽  
Fungal Resistance ◽  
Bacterial Strains ◽  
Fusarium Spp ◽  
Streptomyces Species ◽  
Streptomyces Spp ◽  
Wide Range

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.

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

2019 ◽  
Vol 7 (8) ◽  
pp. 249 ◽  
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.

scholarly journals Effects and Mechanisms of Symbiotic Microbial Combination Agents to Control Tomato Fusarium Crown and Root Rot Disease

2021 ◽  
Vol 12 ◽  
Author(s):  
Xinyue Cai ◽  
Honghai Zhao ◽  
Chen Liang ◽  
Min Li ◽  
Runjin Liu
Keyword(s):  
Enzyme Activity ◽  
Plant Growth ◽  
Root Rot ◽  
Mycorrhizal Fungi ◽  
Plant Growth Promoting Rhizobacteria ◽  
Growth And Yield ◽  
Metabolome Analysis ◽  
Tomato Root ◽  
Tomato Plants ◽  
Crown And Root Rot

This study evaluated the effects and underlying mechanisms of different combinations of plant symbiotic microbes, comprising arbuscular mycorrhizal fungi (AMF), plant growth-promoting rhizobacteria (PGPR), and Trichoderma spp., on tomato Fusarium crown and root rot (TFCRR) resistance. A total of 54 treatments were applied in a greenhouse pot experiment to tomato (Solanum lycopersicum) seedlings inoculated with or without Funneliformis mosseae (Fm), Rhizophagus intraradices (Ri), Trichoderma virens l40012 (Tv), Trichoderma harzianum l40015 (Th), Bacillus subtilis PS1-3 (Bs), Pseudomonas fluorescens PS2-6 (Pf), and Fusarium oxysporum f. sp. radicis-lycopersici (Fo). The symbioses on the tomato root system were well developed, and the composite symbiont generated by AMF + Trichoderma spp. was observed for the first time. Compared with other treatments, Ri + Bs + Tv and Fm + Pf + Tv stimulated the greatest improvements in tomato growth and yield. The combination Ri + Pf + Th + Fo resulted in the strongest biocontrol effects on TFCRR, followed by the treatments Th + Pf + Fo and Ri + Th + Fo. Compared with the Fo treatment, most inoculation treatments improved photosynthetic performance and significantly increased defense enzyme activity in tomato plants, of which the treatment Ri + Pf + Th + Fo showed the highest enzyme activity. Metabolome analysis detected changes in a total of 1,266 metabolites. The number of up-regulated metabolites in tomato plants inoculated with Ri + Pf + Th and Ri + Pf + Th + Fo exceeded that of the Fo treatment, whereas the number of down-regulated metabolites showed the opposite trend. It is concluded that AMF + Trichoderma + PGPR is the most effective combination to promote resistance to TFCRR in tomato. The up-regulation and down-regulation of metabolites regulated by symbiotic microbial genes may be an important mechanism by which root symbiotic microorganisms promote plant growth, increase yield, and improve disease resistance.

scholarly journals Genome Mining of Antimicrobial Gene Clusters from Phyllospheric Bacteria Isolated from Solanum Lycopersicum and Lactuca Sativa to Identify Biocontrol Properties

2021 ◽  
Author(s):  
Claudia Y. Muñoz ◽  
Lu Zhou ◽  
Yunhai Yi ◽  
Oscar P. Kuipers
Keyword(s):  
Antimicrobial Activity ◽  
Plant Growth ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Genome Mining ◽  
Gene Clusters ◽  
Biocontrol Agents ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Microbe Interactions

Abstract BackgroundBiocontrol agents are sustainable eco-friendly alternatives for chemical pesticides that cause adverse effects in the environment and toxicity in animals including humans. An improved understanding of the phyllosphere microbiology is of vital importance for biocontrol development. Most studies have been directed towards beneficial plant-microbe interactions and ignore the pathogens that might affect humans when consuming vegetables. In this study we extended this perspective and investigated potential biocontrol strains isolated from the tomato and lettuce phyllosphere that can promote plant growth and antagonize mammalian pathogens as well as plant pathogens. Subsequently, we mined into their genomes for discovery of antimicrobial biosynthetic gene clusters (BGCs), several of which are good candidates to produce protectants against microbial plant and mammalian pathogens.Results The antimicrobial activity of 69 newly isolated strains from a healthy tomato and lettuce phyllosphere against several plant and mammalian pathogens was determined with plates assays. Three strains with the highest antimicrobial activity against the relevant pathogens were selected and characterized (Bacillus subtilis STRP31, Bacillus velezensis SPL51, and Paenibacillus sp. PL91). All three strains showed a plant growth promotion effect by the production of volatile compounds (VOCs) on tomato and lettuce. In addition, genome mining of these isolates showed the presence of a large variety of biosynthetic gene clusters. A total of 39 BGCs were identified, of which several are already known, such as bacilysin, bacillibactin, surfactin, subtilomycin, etc., but also several novel ones. Further analysis revealed that among the novel BGCs, one NRPS and two bacteriocins are encoded which were analyzed in more depth.Conclusions Several antimicrobial BGCs were found in the selected strains, including the rediscovery of known ones, but also the discovery of novel ones. Our study serves as support for subsequent examination and characterization of novel antimicrobial metabolites, and the possibility of developing biocontrol agents.

scholarly journals Nutrient Competition Mediated Antagonism of Microbes Against Rhizoctonia solani

2018 ◽  
Vol 10 (3) ◽  
pp. 392-399 ◽  
Author(s):  
Mahesh S. YANDIGERI ◽  
Manoj Kumar SOLANKI ◽  
Sudheer KUMAR ◽  
Rajesh Kumar SINGH ◽  
Alok K. SRIVASTAVA
Keyword(s):  
Plant Growth ◽  
Rhizoctonia Solani ◽  
Soil Microcosm ◽  
Root Extract ◽  
Scanning Electron Micrographs ◽  
Nutrient Competition ◽  
Cell Wall Degrading Enzymes ◽  
Tomato Root ◽  
Potato Dextrose Broth

Plant growth-promoting (PGP) microorganisms are beneficial soil micro creatures which may facilitate plant growth by direct or indirect ways. Bacillus amyloliquefaciens MB101 (BA), Streptomyces atrovirens N23 (SA) and Hypocrea lixii NAIMCC-F-01760 (HL) were earlier reported to have the ability to manage the tomato root rot disease caused by Rhizoctonia solani (RS) at some extent. In the present study, effect of nutrient supplementation like potato dextrose broth (PDB) and tomato root extract (TRE) on antagonism of these three microbes was characterized under the soil microcosm in order to understand the role of nutrient in microbe-microbe interaction. A moderate influence on the population of all three antagonists was resulted by PDB and TRE with RS. However, TRE and PDB were causing a significant impact on cell wall degrading enzymes and antifungal activity in the presence of RS. Moreover, hyphal degradation of RS was proved by scanning electron micrographs in the absence of substrates. Nutrient competition enhanced the call wall degrading enzyme production. Therefore, the present study concluded the role of substrate in the mycoparasitism and also sustain the potential of the hereby methodology (soil microcosm) for screening of other soil-inhibiting organism in the future.

scholarly journals Pseudozyma aphidis Induces Salicylic-Acid-Independent Resistance to Clavibacter michiganensis in Tomato Plants

Plant Disease ◽  
2015 ◽  
Vol 99 (5) ◽  
pp. 621-626 ◽  
Author(s):  
Omer Barda ◽  
Or Shalev ◽  
Shanee Alster ◽  
Kobi Buxdorf ◽  
Aviva Gafni ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Crop Production ◽  
Xanthomonas Campestris ◽  
Plant Pathogens ◽  
Biologically Active ◽  
Biocontrol Agents ◽  
Clavibacter Michiganensis ◽  
Tomato Plants ◽  
Pseudozyma Aphidis

The ability of plant pathogens to rapidly develop resistance to commonly used pesticides challenges efforts to maximize crop production. Fungal biocontrol agents have become an important alternative to chemical fungicides as a result of environmental concerns regarding conventional pesticides, including resistance issues. The complex mode of action of biocontrol agents reduces the likelihood that pathogens will develop resistance to them. We recently isolated a unique, biologically active isolate of the epiphytic fungus Pseudozyma aphidis. We show that the extracellular metabolites secreted by our P. aphidis isolate can inhibit Xanthomonas campestris pv. vesicatoria, X. campestris pv. campestris, Pseudomonas syringae pv. tomato, Erwinia amylovora, Clavibacter michiganensis, and Agrobacterium tumefaciens in vitro. Moreover, application of Pseudozyma aphidis spores on tomato plants in the greenhouse significantly reduced (by 60%) the incidence of bacterial wilt and canker disease caused by C. michiganensis subsp. michiganensis on those plants as well as disease severity by 35%. Furthermore, infected plants treated with P. aphidis were 25% taller than control infected plants. We found that P. aphidis activates PR1a—and other pathogenesis-related genes in tomato plants—and can trigger an induced-resistance response against C. michiganensis that proceeds in a salicylic-acid-independent manner, as shown using NahG-transgenic tomato plants.

scholarly journals Plant-Growth-Promoting Bacteria (PGPB) against Insects and Other Agricultural Pests

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 861 ◽  
Author(s):  
Luca Ruiu
Keyword(s):  
Plant Growth ◽  
Plant Pathogens ◽  
Plant Growth Promoting Bacteria ◽  
Agricultural Pests ◽  
Streptomyces Species ◽  
Plant Growth Promoting ◽  
Rhizobial Species ◽  
Growth Promoting ◽  
Further Development ◽  
Chemical Pesticides

The interest in using plant-growth-promoting bacteria (PGPB) as biopesticides is significantly growing as a result of the discovery of new properties of certain beneficial microbes in protecting agricultural crops. While several rhizobial species have been widely exploited for their ability to optimize plant use of environmental resources, now the focus is shifted to species that are additionally capable of improving plant health and conferring resistance to abiotic stress and deleterious biotic agents. In some cases, PGPB species may directly act against plant pathogens and parasites through a variety of mechanisms, including competition, protective biofilm formation, and the release of bioactive compounds. The use of this type of bacteria is in line with the principles of ecosustainability and integrated pest management, including the reduction of employing chemical pesticides. Several strains of Bacillus, Paenibacillus, Brevibacillus, Pseudomonas, Serratia, Burkholderia, and Streptomyces species have been the subject of specific studies in this direction and are under evaluation for further development for their use in biological control. Accordingly, specific case studies are presented and discussed.

Sign in / Sign up

Export Citation Format

Share Document