scholarly journals Microbial Biocontrol Strategies for Ambrosia Beetles and Their Associated Phytopathogenic Fungi

2021 ◽  
Vol 5 ◽  
Author(s):  
Frédérique Reverchon ◽  
Silvia M. Contreras-Ramos ◽  
Akif Eskalen ◽  
José A. Guerrero-Analco ◽  
Evangelina E. Quiñones-Aguilar ◽  
...  

Ambrosia beetles and their symbiotic fungi are causing severe damage in natural and agro-ecosystems worldwide, threatening the productivity of several important tree crops such as avocado. Strategies aiming at mitigating their impact include the application of broad-spectrum agrochemicals and the incineration of diseased trees, but the increasing demand for environment-friendly strategies call for exploring biological control for the management of ambrosia beetles and their phytopathogenic fungal symbionts. The aim of this review is to examine the existing knowledge on biocontrol approaches using beneficial microorganisms and microbial natural products with entomopathogenic and antifungal activity against ambrosia beetles and fungi. We show that biocontrol has been mainly focused on the insect, using entomopathogenic fungi (EPF) such as Beauveria spp. or Metarhizium spp. However, recent studies have been integrating EPF with mycoparasitic fungi such as Trichoderma spp. to simultaneously challenge the vector and its fungal symbionts. Novel approaches also include the use of microbial natural products as insect lures or antifungal agents. Contrastingly, the potential of bacteria, including actinobacteria (actinomycetes), as biocontrol agents of ambrosia fungi has been little investigated. We thus suggest that future research should further examine the antifungal activity of bacterial strains, with an emphasis on harsh environments. We also suggest pursuing the isolation of more effective microbial strains with dual biocontrol effect, i.e., exhibiting fungicidal/insecticidal activities. Moreover, additional efforts should aim at determining the best application methods of biocontrol agents in the field to ensure that the positive effects detected in vitro are sustained. Finally, we propose the integration of microbiome studies in pest and disease management strategies as they could provide us with tools to steer the beneficial host plant microbiome and to manipulate the beetle microbiome in order to reduce insect fitness.

2020 ◽  
Vol 110 (11) ◽  
pp. 1740-1750
Author(s):  
Flavia Occhibove ◽  
Daniel S. Chapman ◽  
Alexander J. Mastin ◽  
Stephen S. R. Parnell ◽  
Barbara Agstner ◽  
...  

In order to prevent and control the emergence of biosecurity threats such as vector-borne diseases of plants, it is vital to understand drivers of entry, establishment, and spatiotemporal spread, as well as the form, timing, and effectiveness of disease management strategies. An inherent challenge for policy in combatting emerging disease is the uncertainty associated with intervention planning in areas not yet affected, based on models and data from current outbreaks. Following the recent high-profile emergence of the bacterium Xylella fastidiosa in a number of European countries, we review the most pertinent epidemiological uncertainties concerning the dynamics of this bacterium in novel environments. To reduce the considerable ecological and socio-economic impacts of these outbreaks, eco-epidemiological research in a broader range of environmental conditions needs to be conducted and used to inform policy to enhance disease risk assessment, and support successful policy-making decisions. By characterizing infection pathways, we can highlight the uncertainties that surround our knowledge of this disease, drawing attention to how these are amplified when trying to predict and manage outbreaks in currently unaffected locations. To help guide future research and decision-making processes, we invited experts in different fields of plant pathology to identify data to prioritize when developing pest risk assessments. Our analysis revealed that epidemiological uncertainty is mainly driven by the large variety of hosts, vectors, and bacterial strains, leading to a range of different epidemiological characteristics further magnified by novel environmental conditions. These results offer new insights on how eco-epidemiological analyses can enhance understanding of plant disease spread and support management recommendations. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .


2020 ◽  
Vol 25 (10) ◽  
pp. 1123-1140
Author(s):  
Jilan Nazeam ◽  
Esraa Z. Mohammed ◽  
Mariam Raafat ◽  
Mariam Houssein ◽  
Asmaa Elkafoury ◽  
...  

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative pathogen of pandemic coronavirus disease 2019 (COVID-19). So far, no approved therapy has been developed to halt the spread of the pathogen, and unfortunately, the strategies for developing a new therapy will require a long time and very extensive resources. Therefore, drug repurposing has emerged as an ideal strategy toward a smart, versatile, quick way to confine the lethal disease. In this endeavor, natural products have been an untapped source for new drugs. This review represents the confederated experience of multidisciplinary researchers of 99 articles using several databases: Google Scholar, Science Direct, MEDLINE, Web of Science, Scopus, and PubMed. To establish the hypothesis, a Bayesian perspective of a systematic review was used to outline evidence synthesis. Our docking documentation of 69 compounds and future research agenda assumptions were directed toward finding an effective and economic anti-COVID-19 treatment from natural products. Glucosinolate, flavones, and sulfated nitrogenous compounds demonstrate direct anti-SARS-CoV-2 activity through inhibition protease enzymes and may be considered potential candidates against coronavirus. These findings could be a starting point to initiate an integrative study that may encompass interested scientists and research institutes to test the hypothesis in vitro, in vivo, and in clinics after satisfying all ethical requirements.


2021 ◽  
Vol 11 ◽  
Author(s):  
Francisco Massot ◽  
Panagiotis Gkorezis ◽  
Jonathan Van Hamme ◽  
Damian Marino ◽  
Bojana Spirovic Trifunovic ◽  
...  

The large-scale use of the herbicide glyphosate leads to growing ecotoxicological and human health concerns. Microbe-assisted phytoremediation arises as a good option to remove, contain, or degrade glyphosate from soils and waterbodies, and thus avoid further spreading to non-target areas. To achieve this, availability of plant-colonizing, glyphosate-tolerant and -degrading strains is required and at the same time, it must be linked to plant-microorganism interaction studies focusing on a substantive ability to colonize the roots and degrade or transform the herbicide. In this work, we isolated bacteria from a chronically glyphosate-exposed site in Argentina, evaluated their glyphosate tolerance using the minimum inhibitory concentration assay, their in vitro degradation potential, their plant growth-promotion traits, and performed whole genome sequencing to gain insight into the application of a phytoremediation strategy to remediate glyphosate contaminated agronomic soils. Twenty-four soil and root-associated bacterial strains were isolated. Sixteen could grow using glyphosate as the sole source of phosphorous. As shown in MIC assay, some strains tolerated up to 10000 mg kg–1 of glyphosate. Most of them also demonstrated a diverse spectrum of in vitro plant growth-promotion traits, confirmed in their genome sequences. Two representative isolates were studied for their root colonization. An isolate of Ochrobactrum haematophilum exhibited different colonization patterns in the rhizoplane compared to an isolate of Rhizobium sp. Both strains were able to metabolize almost 50% of the original glyphosate concentration of 50 mg l–1 in 9 days. In a microcosms experiment with Lotus corniculatus L, O. haematophilum performed better than Rhizobium, with 97% of glyphosate transformed after 20 days. The results suggest that L. corniculatus in combination with to O. haematophilum can be adopted for phytoremediation of glyphosate on agricultural soils. An effective strategy is presented of linking the experimental data from the isolation of tolerant bacteria with performing plant-bacteria interaction tests to demonstrate positive effects on the removal of glyphosate from soils.


2019 ◽  
Vol 72 (4) ◽  
Author(s):  
Ewa Dorota Król ◽  
Barbara Anna Abramczyk ◽  
Beata Zimowska ◽  
Ewa Dorota Zalewska

Six fungicides from various chemical groups and two natural products, i.e., Biosept Active (grapefruit extract) and Beta-Chikol (chitosan) were tested in vitro against <em>Diaporthe eres</em> isolated from the shoots of fruit trees. The preparations were incorporated in PDA medium to provide final fungicide concentrations of 1, 10, and 100 g cm<sup>−3</sup>. Biosept Active concentrations of 0.05%, 0.075%, and 0.1%, and Beta-Chikol concentrations of 1%, 2%, and 2.5%, respectively. The antifungal activity of the preparations was evaluated based on mycelial growth of <em>D. eres</em> strains after 4 and 8 days of culture and changes in the morphological structures of the fungus. The highest antifungal activity was registered for thiophanate-methyl at all tested concentrations, followed by thiram, which showed the same activity but only at 100 g cm<sup>−3</sup>. Among the preparations of natural origin, Beta-Chikol was more effective against <em>D. eres</em> than Biosept Active. The effects achieved by the former preparation were comparable with those achieved by some of the most effective fungicides tested against <em>D. eres</em>.


Author(s):  
Mahdi Vajdi ◽  
Mahdieh Abbasalizad Farhangi

Abstract. The prevalence of obesity has increased substantially over the last several decades and several environmental factors have accelerated this trend. Poly-methoxy flavones (PMFs) exist abundantly in the peels of citrus, and their biological activities have been broadly examined in recent years. Several studies have examined the effects of PMFs on obesity and its-related diseases. This systematic review conducted to focus on the effect of PMFs on obesity and its related conditions management. The PubMed, Google Scholar, Scopus, and Science Direct databases were searched for relevant studies published before November 2020. Out of 1,615 records screened, 16 studies met the study criteria. The range of dosage of PMFs was varied from 10 to 200 mg/kg (5–26 weeks) and 1–100 μmol (2h–8 days) across selected animal and in vitro studies, respectively. The literature reviewed shows that PMFs modulate several biological processes associated with obesity such as lipid and glucose metabolism, inflammation, energy balance, and oxidative stress by different mechanisms. All of the animal studies showed significant positive effects of PMFs on obesity by reducing body weight (e.g. reduced weight gain by 21.04%), insulin resistance, energy expenditure, inhibiting lipogenesis and reduced blood lipids (e.g. reduced total cholesterol by 23.10%, TG by 44.35% and LDL by 34.41%). The results of the reviewed in vitro studies have revealed that treatment with PMFs significantly inhibits lipid accumulation in adipocytes (e.g. reduced lipid accumulation by 55–60%) and 3T3-L1 pre-adipocyte differentiation as well by decreasing the expression of PPARγ and C/EBPα and also reduces the number and size of fat cells and reduced TG content in adipocytes by 45.67% and 23.10% and 16.08% for nobiletin, tangeretin and hesperetin, respectively. Although current evidence supports the use of PMFs as a complementary treatment in obesity, future research is needed to validate this promising treatment modality.


1996 ◽  
Vol 42 (7) ◽  
pp. 690-700 ◽  
Author(s):  
Paige E. Axelrood ◽  
Alison M. Clarke ◽  
Reed Radley ◽  
S. Janet V. Zemcov

A microbial culture collection composed of 1820 bacterial strains, including 298 actinomycete strains, was established from the roots of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings harvested from conifer nurseries and forest sites. Two hundred and thirty-four strains inhibited the growth of Fusarium, Cylindrocarpon, and (or) Pythium spp. in in vitro assays. A significantly greater proportion of bacterial strains from actinomycete genera exhibited antifungal properties compared with bacterial strains from nonactinomycete genera. Eighty-nine percent of identified inhibitory strains were Streptomyces, Streptoverticillium, Bacillus, Pseudomonas, or Burkholderia species. The actinomycete species were isolated almost exclusively from forest seedlings. Recovery of inhibitory strains representing 29 microbial species was enhanced using a variety of methods to isolate microorganisms from the roots of seedlings from nursery and forest sites. Bacterial strains (including actinomycete strains) with antifungal activity were tested for in vitro growth inhibition of six clinical human bacterial pathogens (Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa). Forty-eight percent of the tested strains inhibited one or more human pathogens. Inhibitory activity towards fungal and bacterial pathogens was strain specific, not species specific, and many inhibitory strains exhibited broad-spectrum activity. Strains with antifungal activity against several conifer root pathogens were also more likely to inhibit multiple species of clinical bacterial pathogens.Key words: in vitro, antimicrobial, conifer rhizosphere.


2019 ◽  
Vol 31 (12) ◽  
pp. 2733-2739 ◽  
Author(s):  
Srinivasa Rao Dasari ◽  
Subbaiah Tondepu ◽  
Lakshmana Rao Vadali ◽  
Nareshvarma Seelam

A novel series of pyrazole benzimidazole derivatives were synthesized and the structure of the final targets 4a-h were confirmed by IR, Mass, 13C NMR and 1H NMR spectral analysis. The new pyrazole core with imidazole and benzimidazoles derivatives were evaluated for in vitro antibacterial, antifungal activity against six bacterial strains significantly. In dispersion, 4c, 4f and 4g had the highest antibacterial activities on these microorganisms Bacillus subtilis B29, Escherichia coli E266, with zone of inhibition 21, 19 and 19 mm, respectively. Compounds 4a, 4c, 4h shows good antifungal activity against A. niger, Fusarium oxysporum fungal strains. Further, molecular docking for protein ligands interactions was performed using the crystal structure of C(30) carotenoid dehydrosqualene synthase from Staphylococcus aureus complexed with bisphosphonate BPH-700. Among the final compounds 4e, 4g and 4h show highest binding energy ΔG = -7.89, -7.48 and -7.08 Kcal/mol, respectively and amino acid interactions Lys273, Asp27.


2017 ◽  
Vol 61 (3) ◽  
Author(s):  
Ashok Dongamanti ◽  
Mohammad Ziauddin ◽  
Bommidi Vijaya Lakshmi ◽  
Madderla Sarasija

A series of ten novel (<em>E</em>)-(4-(aryl)phenyl)(3-(2-(1-phenyl-3- (thiophen-2-yl)-1<em>H</em>-pyrazol-4-yl)vinyl)benzofuran-2-yl)methanones (<strong>7a-j</strong>) derivatives were prepared by traditional Claisen-Schmidt and Suzuki cross-coupling reaction under conventional and microwave irradiation conditions. The structures of all the newly synthesized compounds were established on the basis of FTIR, <sup>1</sup>H NMR, <sup>13</sup>C NMR, mass spectral data and elemental analysis. The products were assayed for their <em>in vitro</em> antibacterial activity against different types of bacterial strains. Further the antifungal activity was examined by inhibitory action against three fungal strains such as <em>Aspergillus niger</em>, <em>Aspergillus flavus</em> and <em>Fusarium oxysporum</em>.


2021 ◽  
Vol 28 ◽  
Author(s):  
Joanda Paolla Raimundo e Silva ◽  
Chonny Alexander Herrera Acevedo ◽  
Thalisson Amorim de Souza ◽  
Renata Priscila Barros de Menezes ◽  
Zoe L. Sessions ◽  
...  

Background: Natural products are useful agents for the discovery of new lead-compounds and effective drugs to combat coronaviruses (CoV). Objective: The present work provides an overview of natural substances, plant extracts, and essential oils as potential antiSARS-CoV agents. In addition, this work evaluates their drug-like properties which are essential in the selection of compounds in order to accelerate the drug development process. Methods: The search was carried out using PubMed, ScienceDirect and SciFinder. Articles addressing plant-based natural products as potential SARS-CoV or SARS-CoV-2 agents within the last seventeen years were analyzed and selected. The descriptors for Chemometrics analyzes were obtained in alvaDesc and the principal component analyzes (PCA) were carried out in SIMCA version 13.0. Results: Based on in vitro assays and computational analyzes, this review covers twenty nine medicinal plant species and more than 300 isolated substances as potential anti-coronavirus agents. Among them, flavonoids and terpenes were the most promising compound classes. In silico analyses of drug-like properties corroborate these findings and indicate promising candidates for in vitro and in vivo studies to validate their activity. Conclusion: This paper highlights the role of ethnopharmacology in drug discovery and simulates the use of integrative (in silico/ in vitro) and chemocentric approaches to strengthen current studies and guide future research in the field of antivirals agents.


2018 ◽  
Vol 16 (1) ◽  
pp. 93-100
Author(s):  
Hind Benouda ◽  
Btissam Bouchal ◽  
Allal Challioui ◽  
Abdelkader Oulmidi ◽  
Tarik Harit ◽  
...  

Background: A series of chalcones and flavones were synthesized from 2’-hydroxyacetophenone and substituted aromatic aldehydes via Simmons-Schmidt condensation followed by oxidative cyclization. Methods: Characterization of the obtained structures was established on the basis of their spectroscopic data. The synthesized compounds were screened for their antimicrobial activities against five bacterial strains (Citrobacter freundii, Staphylococcus aureus, Listeria monocytogenes, Salmonella braenderup, Escherichia coli.) and two fungal strains (Candida albicans, Candida krusei). Results: The in vitro bioassay results indicated that some target compounds displayed moderate (4d, 4e) to high (4a) antifungal activity against the pathogenic fungi C. albicans and C. krusei. Conclusion: For the antibacterial activity, only products 3d and 4d showed a weak antibacterial activity. These compounds can lead to the design of new drugs with specific antifungal activity.


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