scholarly journals Use of Streptomyces species as a Biological Agent Against Plant Pathogens

2021 ◽  
Vol 2 (4) ◽  
pp. 151-158
Author(s):  
Duygu Seren Özyılmaz ◽  
Muhammed Hasan Akyıl
Keyword(s):  
Plant Pathogens ◽  
Biological Agent ◽  
Streptomyces Species

AMIDOMYCIN, A NEW ANTIBIOTIC FROM A STREPTOMYCES SPECIES. PRODUCTION, ISOLATION, ASSAY, AND BIOLOGICAL PROPERTIES

1957 ◽  
Vol 3 (7) ◽  
pp. 953-965 ◽  
Author(s):  
W. A. Taber ◽  
L. C. Vining
Keyword(s):  
Candida Albicans ◽  
Plant Pathogens ◽  
Degradation Products ◽  
Biological Properties ◽  
Puccinia Graminis ◽  
Serial Transfer ◽  
Streptomyces Species ◽  
Low Concentrations ◽  
Agar Media ◽  
Species Production

Antifungal preparations were obtained from cultures of Streplomyces PRL 1642 by solvent extraction of the solids collected after the pH was adjusted to 3.5. The active factor, named amidomycin, was purified by repeated crystallization from aqueous ethanol or petrol (b.p. 60°–80 °C.) to give stable, colorless, optically active needles, m.p. 192 °C.Amidomycin suspended in agar media retarded the growth of many filamentous fungi and noticeably inhibited the plant pathogens Ustilago maydis, Ustilago trebouxii, as well as the human pathogen, Hormodendrum pedrosoi. It also inhibited the germination of uredospores of Puccinia graminis at low concentrations. Certain yeasts were completely inhibited by small concentrations of amidomycin; the quantity required was affected by the number of cells in the inoculum.None of the bacteria examined was inhibited by this antibiotic. At certain concentrations it was lethal to Candida albicans as determined by the inability of previously exposed and washed cells to grow on nutrient agar.Although a few isolated colonies of Candida albicans usually developed on plates containing approximately double the concentration required to inhibit growth of the inoculum streak, serial transfer of progeny from such colonies onto agar containing amidomycin did not produce cultures having progressively increasing resistance.Two degradation products of amidomycin, D(–)-valine and 3,6-diisopropyl-2,5-diketomorpholine, are inactive.

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

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.

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 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.

Freeze substitution fixation of fungal reproductive structures and spores

1989 ◽  
Vol 47 ◽  
pp. 990-991
Author(s):  
C. W. Mims ◽  
E. A. Richardson
Keyword(s):  
Plant Pathogens ◽  
Freeze Substitution ◽  
Uranyl Acetate ◽  
Chemical Fixation ◽  
Dialysis Membrane ◽  
Razor Blade ◽  
Thin Sections ◽  
Reproductive Structures ◽  
Dry Down ◽  
Diamond Knife

The advantages of freeze substitution fixation over conventional chemical fixation for preservation of ultrastructural details in fungi have been discussed by various authors. As most ascomycetes, basidiomycetes and deuteromycetes do not fix well using conventional chemical fixation protocols, freeze substitution has attracted the attention of many individuals interested in fungal ultrastructure. Thus far most workers using this technique on fungi have concentrated on thin walled somatic hyphae. However, in our laboratory we have experimented with the use of freeze substitution on a variety of fungal reproductive structures and spores with promising results.Here we present data on freeze substituted samples of sporangia of the zygomycete Umbellopsis vinacea, basidia of Exobasidium camelliae var. gracilis, developing teliospores of the smut Sporisorium sorghi, germinating teliospores of the rust Gymnosporangium clavipes, germinating conidia of the deuteromycete Cercosporidium personatum, and developing ascospores of Ascodesmis nigricans.Spores of G. clavipes and C. personatum were deposited on moist pieces of sterile dialysis membrane where they hydrated and germinated. Asci of A. nigricans developed on pieces of dialysis membrane lying on nutrient agar plates. U. vinacea was cultured on small pieces of agar-coated wire. In the plant pathogens E. camelliae var. gracilis and S. sorghi, a razor blade was used to remove smal1 pieces of infected host issue. All samples were plunged directly into liquid propane and processed for study according to Hoch.l Samples on dialysis membrane were flat embedded. Serial thin sections were cut using a diamond knife, collected on slot grids, and allowed to dry down onto Formvar coated aluminum racks. Sections were post stained with uranyl acetate and lead citrate.

Effect of Homeopathic Preparations on Lettuce, Parasitized or Not by Meloidogyne enterolobii

Homeopathy ◽  
2020 ◽  
Author(s):  
Thais Moraes Ferreira ◽  
Mariana Zandomênico Mangeiro ◽  
Alexandre Macedo Almeida ◽  
Ricardo Moreira Souza
Keyword(s):  
Plant Pathogens ◽  
Nematode Control ◽  
Plant Tolerance ◽  
Nematode Reproduction ◽  
Meloidogyne Enterolobii ◽  
Negative Effect ◽  
Meloidogyne Spp ◽  
Constant Dose ◽  
Lettuce Growth ◽  
Complementary Strategy

Abstract Background There are relatively few scientific works on the use of homeopathy to manage plant pathogens, particularly nematodes. A handful of studies focused on Meloidogyne spp. parasitizing vegetables have brought contradictory results on nematode control and enhancement of plant tolerance to parasitism. Objective Our goal was to assess the effect of Cina—a well-known anti-nematode ingredient—on Meloidogyne enterolobii parasitizing lettuce. Methods Cina was applied daily on nematode-inoculated plants, from the seedling stage until harvest. We tested an evenly spaced range of Hahnemannian concentrations (c), which were applied though irrigation with a constant dose of the ingredient. Several absolute and relative controls were employed to allow the assessment of the effect of Cina on nematode reproduction and lettuce growth. Results Cina affected growth of non-parasitized plants, both positively and negatively; this effect was modulated by the c applied and the thermal stress suffered by the plants in one of the assays. The effect of Cina on the growth of nematode-parasitized plants was neutral or negative. Cina reduced nematode reproduction by 25–36%. Conclusion Based on the moderate negative effect of Cina on M. enterolobii reproduction, it seems this ingredient may be useful as a complementary strategy for Meloidogyne control. But Cina did not enhance the tolerance of lettuce to Meloidogyne spp.

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