scholarly journals Potential Biological Control Agents for Soilborne Fungal Pathogens in Tennessee Snap Bean Farms

HortScience ◽  
2020 ◽  
Vol 55 (7) ◽  
pp. 988-994
Author(s):  
Jacqueline Joshua ◽  
Margaret T. Mmbaga

Fungi isolated from snap bean roots and rhizosphere soil where fungicides are not used included Fusarium oxysporum, Fusarium equiseti, Fusarium subglutinans, Fusarium camptoceras, Fusarium chlamydosporum, Fusarium verticillioides, Fusarium proliferatum, Fusarium acuminatum, Fusarium solani, Peyronellaea pinodella, Macrophomina phaseolina, and Glomerella guttata. Only P. pinodella, M. phaseolina, and F. oxysporum were isolated on symptomatic plants. These soilborne fungi are common pathogens of diverse host plants. Pathogenicity tests under controlled environment demonstrated that these fungi were pathogenic on snap beans. Subsequently, bacterial endophytes isolated from snap bean roots, papaya roots and stems, and dogwood stems were evaluated as potential biological control agents against these diverse fungi. All bacteria isolated, including Bacillus vallismortis (PS), Bacillus amyloliquefaciens (Psl), Bacillus subtilis (Prt), Bacillus thuringiensis (Y and IMC8), Enterobacter sp. (E), Stenotrophomonas sp. (B17A), and Serratia sp. (B17B) suppressed growth of the fungal pathogens in vitro and formed clear inhibition zones in petri dish dual cultures. Growth media taken from the inhibition zones suppressed growth of the fungal pathogens in the absence of the bacterial cells, suggesting that the bacteria released unidentified antagonistic biochemical substances into the media. This study constitutes an initial screening of endophytes as biological control agents against diverse fungal pathogens and forms a basis for the discovery of novel strains that can be further developed and integrated into disease management systems for diverse fungal pathogens. Isolates B. vallismortis (PS), B. amyloliquefaciens (Psl), B. subtilis (Prt), and B. thuringiensis (Y IMC8) exhibited the best performance as potential biological control agents paving the way for larger-scale in vivo studies and characterization of their interactions with fungal pathogens.

2017 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Tatsuya Ohike ◽  
Minori Maeda ◽  
Tetsuya Matsukawa ◽  
Masahiro Okanami ◽  
Shin’ichiro Kajiyama ◽  
...  

Rhizoctonia solani is fungal plant pathogen that infects many different host plants. Recently, biological control agents that are friendly to the environment and ecosystems have attracted much attention as an alternative to the use of chemical fungicide which have been used worldwide to control soil borne pathogens including R. solani. In this study, 53 strains of actinomycetes isolated from environmental soils, and antifungal activities of them were assessed by the dual culture assay. Strain KT showed strong inhibitory activities against 8 phytopathogenic fungi. A great suppressive effect on R. solani growth was observed in the inoculation test of plants using cucumber and chin-geng-sai. In addition, infection of Bipolaris oryzae also could be suppressed in the detached leaf assay using oats. As a result of genetic analysis, it was shown that KT was a species closely related to Streptomyces lavenduligriseus NRRL B-3173T. However, as far as we know, there is no report for biological control agents using S. lavenduligriseus. This study suggests that the strain KT may useful as biological control agents to suppress various crop diseases.


2021 ◽  
Author(s):  
Robert Blundell ◽  
Molly Arreguin ◽  
Akif Eskalen

SummaryGrapevine trunk diseases (GTDs) threaten the economic sustainability of viticulture worldwide causing a significant reduction of both yields and quality of grapes. Biological control presents a promising sustainable alternative to cultural and chemical methods to mitigate the effects of pathogens causing GTDs, including Botryosphaeria dieback, Eutypa dieback and Esca. This study aimed to identify naturally occurring potential biological control agents from a variety of grapevine tissues, including sap, cane and pith and evaluate their antagonistic activity against selected fungal pathogens responsible for GTDs in vitro. Bacterial and fungal isolates were preliminary screened in vitro to determine their antifungal activity via a dual culture assay against Neofusicoccum parvum and Eutypa lata. Among the fungal isolates, Trichoderma spp. inhibited E. lata mycelial growth up to 64% and N. parvum mycelial growth up to 73% with overgrowth and stopped growth being the likely antagonistic mechanisms. Among the bacterial isolates, Bacillus spp. inhibited E. lata mycelial growth up to 20% and N. parvum mycelial growth up to 40%. Select antagonistic isolates of Trichoderma, Bacillus and Aureobasidium spp. were subject to further dual culture antifungal analysis against Diplodia seriata and Diaporthe ampelina, with Trichoderma isolates consistently causing the greatest inhibition. Volatile organic compound antifungal analysis revealed that these Trichoderma isolates resulted significantly inhibited mycelial growth of N. parvum, E. lata and D. ampelina causing up to 20.11%, 60.55% and 70.9% inhibition respectively (P≤0.05). Multilocus sequence analysis revealed that the Trichoderma isolates are most closely related to Trichoderma asperellum and Trichoderma hamatum. This study identifies grapevine sap as a novel source of potential biological control agents for control of GTDs to support existing efforts to control GTDs. Further testing will be necessary to fully characterize these microbes mode of antagonism and assess their efficacy for pruning wound protection in planta.


Author(s):  
Arapat Rustamovna Bagavova ◽  
◽  
Natal’ya S. Velichko ◽  
Timofey E. Pylayev ◽  
Yuliya P. Fedonenko ◽  
...  

The Herbaspirillum lusitanum P6-12 strain containing the vector plasmid pJN105TurboGFP, which encodes the synthesis of the green fluorescent protein GFP, and which has resistance to the antibiotic gentamicin, was obtained by electroporation. The constructed strain of H. lusitanum P6-12 in cultural, morphological and biochemical properties did not differ from the original typical natural strain of H. lusitanum P6-12. On solid growth media, the recombinant strain formed yellow-green colonies, fluorescent under UV irradiation. Upon inoculation with the resulting culture of plant objects, a green glow of the marked H. lusitanum P6-12 cells, actively colonizing the internal tissues of the host plant, was observed. The created strain can be used as a model strain for studying the patterns and characteristics of the behaviour of organisms in integrated systems, including for tracking bacterial cells during interaction with plants, assessing their survival, competitiveness, etc.


2020 ◽  
Vol 18 ◽  
Author(s):  
Ramyar Rahimi Darehbagh ◽  
Rojin Ramezani ◽  
Afra Hosseinpanahi ◽  
Ahmad Fotoohi ◽  
Samaneh Rouhi

Background: Medicinal herbs such as Pistacia atlantica (P. atlantica) subsp. Kurdica have antimicrobial effects. The present study is aimed to investigate the nanocluster structure of P. atlantica subsp. Kurdica turpentine and its composing elements and antibacterial effect. Methods: 100 μl ethanol was used to dissolve oily turpentine. 2, 2.2, 2.4, and 2.6 µg/μl of turpentine were used for investigating the antibacterial effects using disk and well diffusion methods. Elemental and nanocluster structure analyses were performed by Energy-Dispersive XRay Microanalysis (EDXMA) and Field Emission (FE)-scanning electron. Two-way analysis of variance (ANOVA) and Bonferoni test were used for data analysis (p ≤ 0.001). Results and Discussion: EDXMA elemental analysis of turpentine included: zinc (Zn), magnesium (Mg), fluorine (F), oxygen (O), silicium (Si), carbon (C), and argentum (Ag). A topography image of the turpentine showed a nanocluster surface with bright clusters in the background. The largest diameters of the growth inhibition zones (24.67 ± 0.58 mm in the disk diffusion and 23.67 ± 1.53 mm in the well diffusion) that were created by turpentine were observed against S. aureus ATCC 25923 at the concentration of 2.6 µg/μl. Diameter of the inhibition zone around bacterial growth had a direct relationship with turpentine concentration (p ≤ 0.001). Conclusion: The nanocluster structure of turpentine and its composed elements were detected in this research. Moreover, antibacterial effects of turpentine were proved. Herbal substances are widely used in medical applications. Different elements of P. atlantica subsp. Kurdica turpentine can be used as antibacterial agents, but more in-vitro and in-vivo studies should be performed in this field.


Author(s):  
NUZHAT TABASSUM ◽  
VIDYASAGAR G. M. ◽  
RAGHUNANDAN D ◽  
SHIVAKUMAR I

Objectives: The aim of the present study is to isolate an antifungal compound from Derris indica (Lam) Bennett seed oil with various solvents and evaluation of its antifungal activity against the clinical species of Candida. Methods: D. indica seed hexane extract was tested against Trichophyton rubrum, Trichophyton tonsurans and Candida albicans. Hexane extract was fractioned using different solvents through column chromatography (CC). Isolated compound D1 was identified and characterized using ultraviolet, Fourier-transform infrared, 1HNMR, and mass spectroscopy. In vitro evaluation of D1 carried out against 12 Candida strains. In vivo evaluation of D1 carried out against T. rubrum, T. tonsurans, and C. albicans using an excision wound healing model on male Wistar rats. Results: Different concentrations of hexane extract showed antimicrobial activity against tested microorganism with varying minimum inhibitory concentration values. On fractionation with hexane-petroleum ether through CC, it yielded a crystalline fraction. Compound D1 characterized as a 3,5-bis (4,4’’-dimethoxy-[1,1’: 2’,1’’-terphenyl]-4’-yl)-4H-pyrazole-4,4-diol. A novel alkaloid compound from D. indica is a new report and proved to be inhibitory against C. albicans MTCC 3017 (14.83±0.28), MTCC 1637 (16.0±0.0), Candida glabrata MTCC 3814 (16.83±0.28) and MTCC 3014 (16.66±0.57), Candida tropicalis MTCC 230 (20.0±0.0), MTCC 1406 (12.33±0.57). C. glabrata MTCC 3981 was found to be resistant to the compound. In vivo studies showed no visual symptoms at the end of treatment indicating the therapeutic property of the compound. Conclusion: The D1 was found to be effective against human fungal pathogens and can be used as a base molecule in designing new antifungal drugs.


2019 ◽  
Vol 19 (1) ◽  
pp. 8
Author(s):  
Wagiyana Wagiyana ◽  
Didik Sulistyanto ◽  
Joko Waluyo

Entomopathogenic Nematodes (EpNs) that serve as biological control agents include Steinernema spp and  Heterorhabditis spp. EPNs Heterorhabditis indicus (Bromo Isolate) has a high toxicity against larvae Lepidoptera and Coleoptera and was successfully developed for mass production in Biological Control Laboratory of Jember University. These nematodes will be formulated as solid and liquid biopesticides. This research aims: to find EPNs local isolates from smallholder coffee plantations; to identify local and in vivo and in vitro cultured EPNs isolates; to determine the pathogenicity of EpNs local isolate against Coffee Berry Borrer (CBB) Hypothenemus hampei Ferr and to formulate EpNs in vitro culture as a liquid and solid formula. These formula were tested for the patogenicity and viability of EpNs to the larvae of H. hampei, Tenebrio molitor and Galleria melonella. The results showed that the pathogenecity of EpNs isolate to the larvae of CBB in Silo was 30% after 24 hours and 90% after 48 hours of in vivo inoculation. However, the mortality of CBB larvae was only 10% by liquid spraying on the coffee berry. The viability was 524 IJ (Infective Juvenile) on liquid formula packed on polyurethane sponge, and this was higher than that on solid formula (330 IJ).


Parasitology ◽  
1982 ◽  
Vol 84 (4) ◽  
pp. 177-204 ◽  
Author(s):  
J. J. Petersen

SUMMARYThis review highlights published research on the principal entomogenous nematodes that have potential as biological control agents of insects. The life-cycles and status of promising members of the families Allantonematidae, Diplogasteridae, Heterorhabditidae, Mermithidae, Neotylenchidae, Rhabditidae, Sphaerulariidae, Steinernematidae and Tetradonematidae are discussed. Emphasis is placed on attempts to control insect populations with these nematodes. Mass propagation of the Steinernematidae and Mermithidae are also discussed, including current in vivo and in vitro rearing systems. A number of these nematodes show promise as biological control agents but commercial development has been slow because of environmental limitations, host specificity and inherent problems associated with manipulation of living organisms. Although some of these nematodes have been considered for commercial preparation, it appears that they will remain ‘on the shelf’ until the need for such biological control provides small businesses with the incentive to make them available for general use.


Plant Disease ◽  
2021 ◽  
Author(s):  
Raja Asad Ali Khan ◽  
Yuanyang Tang ◽  
Ishrat Naz ◽  
Syed Sartaj Alam ◽  
Wenzhao Wang ◽  
...  

Matricaria chamomilla flower extract was used as a biocompatible material for synthesis of zinc oxide nanoparticles (ZnONPs). The synthesized NPs were evaluated for their antibacterial potential in vitro and in vivo against Ralstonia solanacearum that causes devastating bacterial wilt disease in tomato and other crops. Synthesized ZnONPs were further analyzed by UV-Visible spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The synthesized polydisperse ZnONPs were found to be in the size range of 8.9 to 32.6 nm, and at 18.0 µg ml-1 exhibited maximum in vitro growth inhibition of R. solanacearum. SEM analysis of affected bacterial cells showed morphological deformation such as disruption of cell membrane, cell wall and leakage of cell contents. Results of in vivo studies also showed that application of ZnONPs to the artificially inoculated tomato plants with R. solanacearum significantly enhanced the plant growth by reducing bacterial soil population and disease severity as compared to untreated control. Biosynthesized ZnONPs could be an effective approach to control R. solanacearum.


2009 ◽  
Vol 32 (9) ◽  
pp. 545-554 ◽  
Author(s):  
Jeffrey B. Kaplan

Surface-attached colonies of bacteria known as biofilms play a major role in the pathogenesis of medical device infections. Biofilm colonies are notorious for their resistance to antibiotics and host defenses, which makes most device infections difficult or impossible to eradicate. Bacterial cells in a biofilm are held together by an extracellular polymeric matrix that is synthesized by the bacteria themselves. Enzymes that degrade biofilm matrix polymers have been shown to inhibit bio film formation, detach established bio film colonies, and render biofilm cells sensitive to killing by antimicrobial agents. This review discusses the potential use of biofilm matrix-degrading enzymes as anti-biofilm agents for the treatment and prevention of device infections. Two enzymes, deoxyribonuclease I and the glycoside hydrolase dispersin B, will be reviewed in detail. In vitro and in vivo studies demonstrating the anti-biofilm activities of these two enzymes will be summarized, and the therapeutic potential and possible drawbacks of using these enzymes as clinical agents will be discussed.


2021 ◽  
Vol 14 (10) ◽  
pp. 962
Author(s):  
Terenzio Cosio ◽  
Roberta Gaziano ◽  
Guendalina Zuccari ◽  
Gaetana Costanza ◽  
Sandro Grelli ◽  
...  

Retinoids—a class of chemical compounds derived from vitamin A or chemically related to it—are used especially in dermatology, oncohematology and infectious diseases. It has been shown that retinoids—from their first generation—exert a potent antimicrobial activity against a wide range of pathogens, including bacteria, fungi and viruses. In this review, we summarize current evidence on retinoids’ efficacy as antifungal agents. Studies were identified by searching electronic databases (MEDLINE, EMBASE, PubMed, Cochrane, Trials.gov) and reference lists of respective articles from 1946 to today. Only articles published in the English language were included. A total of thirty-nine articles were found according to the criteria. In this regard, to date, In vitro and In vivo studies have demonstrated the efficacy of retinoids against a broad-spectrum of human opportunistic fungal pathogens, including yeast fungi that normally colonize the skin and mucosal surfaces of humans such as Candida spp., Rhodotorula mucilaginosa and Malassezia furfur, as well as environmental moulds such as Aspergillus spp., Fonsecae monofora and many species of dermatophytes associated with fungal infections both in humans and animals. Notwithstanding a lack of double-blind clinical trials, the efficacy, tolerability and safety profile of retinoids have been demonstrated against localized and systemic fungal infections.


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