scholarly journals Identification of Antibiotic Red Pigments of Serratia marcescens F-1-1, a Biocontrol Agent of Damping-off of Cucumber, and Antimicrobial Activity against Other Plant Pathogens.

1998 ◽  
Vol 64 (4) ◽  
pp. 294-298 ◽  
Author(s):  
Hiroshi OKAMOTO ◽  
Zenji SATO ◽  
Mamoru SATO ◽  
Yukiko KOISO ◽  
Shigeo IWASAKI ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Serratia Marcescens ◽  
Plant Pathogens ◽  
Biocontrol Agent ◽  
Damping Off ◽  
Red Pigments

Suppressive efficacy of volatile compounds produced byBacillus mycoideson damping-off pathogens of cabbage seedlings

2018 ◽  
Vol 156 (6) ◽  
pp. 795-809
Author(s):  
J.-S. Huang ◽  
Y.-H. Peng ◽  
K.-R. Chung ◽  
J.-W. Huang
Keyword(s):  
Radial Growth ◽  
Plant Pathogens ◽  
Biocontrol Agent ◽  
Antagonistic Activity ◽  
Yield Losses ◽  
Damping Off ◽  
Cultivation Medium ◽  
Dimethyl Disulphide ◽  
Volatile Organic ◽  
Potential Use

AbstractRhizoctonia solaniKühn andPythium aphanidermatumEdson cause cabbage seedling damping-off, resulting in severe yield losses. The current study demonstrates the production of toxic volatile organic compounds (VOCs) by two strains ofBacillus mycoidesand the evaluation of a potential use ofB.mycoidesas a biocontrol agent to control cabbage damping-off. Two VOCs, dimethyl disulphide and ammonia, were found to reduce radial growth, cause hyphal deformation and result in organelle degeneration in bothR. solaniandP. aphanidermatum. Pathogen hyphae, after being exposed to VOCs, showed poor rigidity, shrinkage, curling and swelling. The amount of VOCs produced byB. mycoidesand the antagonistic activity against plant pathogens varied, depending on the type of medium used to culture bacteria. Application ofB.mycoidescell suspensions to cultivation medium promotes growth of five different plant species tested. Experiments conducted in greenhouses revealed thatB. mycoidesdid not reduce damping-off incidence caused byR.solani. However,B. mycoidesreduced damping-off incidence induced byP. aphanidermatumby as much as 45% on cabbage seedlings. The results provide valuable information on the feasibility of utilizingB. mycoidesas a biocontrol agent in controlling cabbage damping-off.

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.

scholarly journals Myco-Suppression Analysis of Soybean (Glycine max) Damping-Off Caused by Pythium aphanidermatum

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 788
Author(s):  
Shaban R. M. Sayed ◽  
Shaimaa A. M. Abdelmohsen ◽  
Hani M. A. Abdelzaher ◽  
Mohammed A. Elnaghy ◽  
Ashraf A. Mostafa ◽  
...  
Keyword(s):  
Glycine Max ◽  
Biocontrol Agent ◽  
Lateral Roots ◽  
Dry Weight ◽  
Pythium Aphanidermatum ◽  
Damping Off ◽  
Pythium Oligandrum ◽  
Rdna Its ◽  
Half Strength

The role of Pythium oligandrum as a biocontrol agent against Pythium aphanidermatum was investigated to avoid the harmful impacts of fungicides. Three isolates of P. oligandrum (MS15, MS19, and MS31) were assessed facing the plant pathogenic P. aphanidermatum the causal agent of Glycine max damping-off. The tested Pythium species were recognized according to their cultural and microscopic characterizations. The identification was confirmed through sequencing of rDNA-ITS regions including the 5.8 S rDNA. The biocontrol agent, P. oligandrum, isolates decreased the mycelial growth of the pathogenic P. aphanidermatum with 71.3%, 67.1%, and 68.7% through mycoparasitism on CMA plates. While the half-strength millipore sterilized filtrates of P. oligandrum isolates degrade the pathogenic mycelial linear growth by 34.1%, 32.5%, and 31.7%, and reduce the mycelial dry weight of the pathogenic P. aphanidermatum by 40.1%, 37.4%, and 36.8%, respectively. Scanning electron microscopy (SEM) of the most effective antagonistic P. oligandrum isolate (MS15) interaction showed coiling, haustorial parts of P. oligandrum to P. aphanidermatum hyphae. Furthermore, P. oligandrum isolates were proven to enhance the germination of Glycine max seedling to 93.3% in damping-off infection using agar pots and promote germination of up to 80% during soil pot assay. On the other hand, P. oligandrum isolates increase the shoot, root lengths, and the number of lateral roots.

scholarly journals Application of Bio-Friendly Formulations of Chitinase-Producing Streptomyces cellulosae Actino 48 for Controlling Peanut Soil-Borne Diseases Caused by Sclerotium rolfsii

2021 ◽  
Vol 7 (3) ◽  
pp. 167
Author(s):  
Gaber Abo-Zaid ◽  
Ahmed Abdelkhalek ◽  
Saleh Matar ◽  
Mai Darwish ◽  
Muhammad Abdel-Gayed
Keyword(s):  
Open Field ◽  
Biocontrol Agent ◽  
Sclerotium Rolfsii ◽  
Dry Weight ◽  
Culture Broth ◽  
Field Conditions ◽  
Damping Off ◽  
Mycelium Growth ◽  
Particle Size Analyzer ◽  
Cell Pellet

Of ten actinobacterial isolates, Streptomyces cellulosae Actino 48 exhibited the strongest suppression of Sclerotium rolfsii mycelium growth and the highest chitinase enzyme production (49.2 U L−1 min−1). The interaction between Actino 48 and S. rolfsii was studied by scanning electron microscope (SEM), which revealed many abnormalities, malformations, and injuries of the hypha, with large loss of S. rolfsii mycelia density and mass. Three talc-based formulations with culture broth, cell-free supernatant, and cell pellet suspension of chitinase-producing Actino 48 were characterized using SEM, Fourier transform infrared spectroscopy (FTIR), and a particle size analyzer. All formulations were evaluated as biocontrol agents for reducing damping-off, root rot, and pods rot diseases of peanut caused by S. rolfsii under greenhouse and open-field conditions. The talc-based culture broth formulation was the most effective soil treatment, which decreased the percentage of peanut diseases under greenhouse and open-field conditions during two successive seasons. The culture broth formulation showed the highest increase in the dry weight of peanut shoots, root systems, and yielded pods. The transcriptional levels of three defense-related genes (PR-1, PR-3, and POD) were elevated in the culture broth formulation treatment compared with other formulations. Subsequently, the bio-friendly talc-based culture broth formulation of chitinase-producing Actino 48 could potentially be used as a biocontrol agent for controlling peanut soil-borne diseases caused by S. rolfsii.

scholarly journals In Vitro Antimicrobial Activity of Zodia (Evodia suaveolens) Leaf Extract on Pathogenic Agents Dragon Fruit Plant

Jurnal Biota ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 78-85
Author(s):  
Trio Ageng Prayitno ◽  
Nuril Hidayati
Keyword(s):  
Antimicrobial Activity ◽  
Leaf Extract ◽  
Plant Pathogens ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
Leaf Extracts ◽  
Dragon Fruit ◽  
Fruit Plants ◽  
Pathogenic Agents

The use of antimicrobials from plant extracts has not been used optimally to control pathogenic agents in dragon fruit plants. The purpose of this research was to determine the antimicrobial activity of zodia (Evodia suaveolens) leaf extracts on pathogenic agents of dragon fruit plants in vitro. The research method is laboratory research with Completely Randomized Design (CRD). The antimicrobial concentrations of zodia (E. suaveolens) leaf extract used six types including 50%, 60%, 70%, 80%, 90%, and 100% with four replications. The research sample was the leaf of zodia (E. suaveolens), Pseudomonas aeruginosa and Fusarium oxysporum strain Malang. Test the antimicrobial activity of zodia (E. suaveolens) leaf extracts on the growth of P. aeruginosa and F. oxysporum using the disc-diffusion method and wells method. The research instrument was used the observation sheet of the diameter of inhibition zone indicated by the clear zone. The diameter of inhibition zone data were analyzed using the One Way ANOVA test. The results showed that the antimicrobial activity of zodia (E. suaveolens) leaf extract significantly inhibited the growth of P. aeruginosa and F. oxysporum (P <0.05). These results recommend zodia (E. suaveolens) leaf extract as an antimicrobial agent for dragon fruit plant pathogens.

A New Type of Antimicrobial Phenolics Produced by Plant Peroxidase and Its Possible Role in the Chemical Defense Systems against Plant Pathogens

1994 ◽  
Vol 49 (7-8) ◽  
pp. 411-414 ◽  
Author(s):  
Akio Kobayashi ◽  
Yutaka Koguchi ◽  
Hiroshi Kanzaki ◽  
Shin-ichiro Kajiyama ◽  
Kazuyoshi Kawazu
Keyword(s):  
Antimicrobial Activity ◽  
Plant Pathogens ◽  
Ethyl Acetate Extract ◽  
Spectroscopic Techniques ◽  
Antimicrobial Compounds ◽  
Horse Radish Peroxidase ◽  
Plant Peroxidase ◽  
Defense Systems ◽  
New Type ◽  
Bacteria And Fungi

Syringaldehyde readily reacted in the horse-radish peroxidase (HRPOD) system. The ethyl acetate extract of the reaction mixture showed a marked antimicrobial activity against bacteria and fungi. After repeated column chromatography three potential antimicrobial compounds were obtained from the extract. The structural elucidation of active compounds was achieved by a combination of spectroscopic techniques and chemical modification

scholarly journals Inactivation of the Major Hemolysin Gene Influences Expression of the Nonribosomal Peptide Synthetase Gene swrA in the Insect Pathogen Serratia sp. Strain SCBI

2017 ◽  
Vol 199 (21) ◽  
Author(s):  
Lauren M. Petersen ◽  
Kaitlyn LaCourse ◽  
Tim A. Schöner ◽  
Helge Bode ◽  
Louis S. Tisa
Keyword(s):  
Antimicrobial Activity ◽  
Serratia Marcescens ◽  
Virulence Factors ◽  
Nonribosomal Peptide Synthetase ◽  
Mrna Levels ◽  
Insect Pathogen ◽  
Nonribosomal Peptide ◽  
Content Type ◽  
Hemolysin Gene ◽  
Peptide Synthetase

ABSTRACT Hemolysins are important virulence factors for many bacterial pathogens, including Serratia marcescens. The role of the major hemolysin gene in the insect pathogen Serratia sp. strain SCBI was investigated using both forward and reverse-genetics approaches. Introduction of the major hemolysin gene into Escherichia coli resulted in a gain of both virulence and hemolytic activity. Inactivation of this hemolysin in Serratia sp. SCBI resulted in a loss of hemolysis but did not attenuate insecticidal activity. Unexpectedly, inactivation of the hemolysin gene in Serratia sp. SCBI resulted in significantly increased motility and increased antimicrobial activity. Reverse transcription-quantitative PCR (qRT-PCR) analysis of mutants with a disrupted hemolysin gene showed a dramatic increase in mRNA levels of a nonribosomal peptide synthetase gene, swrA, which produces the surfactant serrawettin W2. Mutation of the swrA gene in Serratia sp. SCBI resulted in highly varied antibiotic activity, motility, virulence, and hemolysis phenotypes that were dependent on the site of disruption within this 17.75-kb gene. When introduced into E. coli, swrA increases rates of motility and confers antimicrobial activity. While it is unclear how inactivation of the major hemolysin gene influences the expression of swrA, these results suggest that swrA plays an important role in motility and antimicrobial activity in Serratia sp. SCBI. IMPORTANCE The opportunistic Gram-negative bacteria of the genus Serratia are widespread in the environment and can cause human illness. A comparative genomics analysis between Serratia marcescens and a new Serratia species from South Africa, termed Serratia sp. strain SCBI, shows that these two organisms are closely related but differ in pathogenesis. S. marcescens kills Caenorhabditis nematodes, while Serratia sp. SCBI is not harmful and forms a beneficial association with them. This distinction presented the opportunity to investigate potential differences in regulation of common virulence mechanisms between these two species. With the emergence of antibiotic-resistant microorganisms, there is a widespread need to understand the regulation of pathogenesis. The significance of this study is the presentation of evidence for cross-pathway regulation of virulence factors and how the elimination of one mechanism may be compensated for by the upregulation of others.

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