Inhibition Of Fungal Growth Research Articles

Synthesis and Antiphytopathogenic Activity of Novel Oxazolidine-2,4-diones Bearing Phenoxypyridine Moiety.

In the present study, we conducted optimization of pyramoxadone and synthesized a series of novel oxazolidinediones. Antifungal assays showed that these compounds exhibited moderate to excellent antifungal activity against various pathogens. Further SAR analysis revealed that the introduction of substituents to the benzene ring of the phenoxy group or the inclusion of bulky groups, such as tert-butyl, on the aniline moiety, had a detrimental effect on the activity. However, the inclusion of fluorine atoms in the aniline moiety significantly enhanced the antifungal efficacy. Notably, compound 2-4 displayed significantly higher activity compared to both pyramoxadone and famoxadone against R. solani, B. cinerea, S. sclerotiorum, and P. oryzae, where it demonstrated EC50 values of 1.78, 2.47, 2.33, and 2.23 μg/mL, respectively. Furthermore, compound 2-4 exhibited potent protective and curative effects against the tomato gray mold in vivo. A mechanistic investigation revealed that compound 2-4 significantly impacted the mycelial morphology, inhibited spore germination, and impeded mycelial respiration, ultimately leading to the inhibition of pathogenic fungus growth. These findings indicate that compound 2-4 has the potential to serve as a cyt bc1 inhibitor and should be further investigated for development.

Symbiotic Antimicrobial Effects of Cellulose-Based Bio-Nanocomposite for Disease Management of Agricultural Crops.

In the present work, a bionanocomposite for plant crop protection was prepared by non-toxic biocompatible & biodegradable nanomaterials (Cellulose & TiO2 ) to utilize its synergistic effects against antimicrobial pathogens. The commercially available microcrystalline cellulose has been reduced to a nanometric scale regime using acid hydrolysis, while the standard TiO2 nano-powder of particle size ~20 nm has been used to prepare their nanocomposite (NC). The antibacterial studies via agar well diffusion method demonstrated that after 72 h of incubation, parent nanomaterials Ncell and TiO2 were not showing any activity against phytopathogens X. campestris pv. campestris, and Clavibacter while the nanocomposite's NC's were still effective depicting both bacteriostatic and bactericidal actions. However, the bacterial growth of biocontrol P. fluorescence was not affected by Ncell, TiO2 NPs and NC after 72 h of incubation. The antifungal testing results via poison food agar assay method suggest that the nanocomposite, along with Ncell and TiO2 NPs, exhibited strong inhibition of fungal growth of Phytophthora Spp at 0.125 mg/ml concentration while for F. graminearum, similar effect was observed at 0.25 mg/ml concentration. The nanocomposite has proved its potential by exhibiting longer & stronger synergistic effects against plant pathogens as a good antimicrobial agent for protection of agricultural crops.

Evaluation of the Antifungal Effect of Rhus verniciflua Stokes Extract for Oral Application Potential.

Background and Objectives: This study confirms the possibility of using Rhus verniciflua Stokes (RVS) extract as a natural treatment for oral candidiasis. Materials and Methods: RVS was extracted with 70% ethanol to examine the antioxidant activity through polyphenol, flavonoid content, and DPPH (1,1-diphenyl-2-picrylhydrazyl). To evaluate the antifungal effect against Candida albicans (C. albicans; KCTC 7965/ATCC 10231) and evaluate the stability of RVS, a water-soluble tetrazolium salt (WST-1) assay was performed in human keratinocytes (HaCaT). Results: The findings revealed that RVS extract has fairly high antioxidant activity. The clear zones of the RVS extract against C. albicans increased in diameter due to the inhibition of fungal growth at higher concentrations. Treatment with the 1.25 mg/mL RVS extract had a more than 99% antifungal effect against C. albicans, and the 20 mg/mL RVS extract had a 100% antifungal effect. The WST-1 assay showed that the RVS extract induced low cell viability in the HaCaT cells, which inhibited their proliferation, and the RVS extract is also toxic to normal cells. Conclusions: Although the RVS extract with high antioxidant activity showed clear antifungal activity against C. albicans, it exhibited a low survival rate. Therefore, the development of a safe natural antibiotic is necessary.

The efficient activity of plant essential oils for inhibiting Botrytis cinerea and Penicillium expansum: Mechanistic insights into antifungal activity

Botrytis cinerea and Penicillium expansum produce deterioration in fruit quality, causing losses to the food industry. Thus, plant essential oils (EOs) have been proposed as a sustainable alternative for minimizing the application of synthetic fungicides due to their broad-spectrum antifungal properties. This study investigated the efficacy of five EOs in suppressing the growth of B. cinerea and P. expansum and their potential antifungal mechanisms. EOs of Mentha × piperita L., Origanum vulgare L., Thymus vulgaris L., Eucalyptus globules Labill., and Lavandula angustifolia Mill., were screened for both fungi. The results showed that the EO of T. vulgaris and O. vulgare were the most efficient in inhibiting the growth of B. cinerea and P. expansum. The concentration increase of all EO tested increased fungi growth inhibition. Exposure of fungi to EOs of T. vulgaris and O. vulgare increased the pH and the release of constituents absorbing 260 nm and soluble proteins, reflecting membrane permeability alterations. Fluorescence microscopic examination revealed that tested EOs produce structural alteration in cell wall component deposition, decreasing the hypha width. Moreover, propidium iodide and Calcein-AM stains evidenced the loss of membrane integrity and reduced cell viability of fungi treated with EOs. Fungi treated with EOs decreased the mitochondria activity and the respiratory process. Therefore, these EOs are effective antifungal agents against B. cinerea and P. expansum, which is attributed to changes in the cell wall structure, the breakdown of the cell membrane, and the alteration of the mitochondrial activity.

Anti-fungal bioactive terpenoids in the bioenergy crop switchgrass (Panicum virgatum) may contribute to ecotype-specific microbiome composition

Plant derived bioactive small molecules have attracted attention of scientists across fundamental and applied scientific disciplines. We seek to understand the influence of these phytochemicals on rhizosphere and root-associated fungi. We hypothesize that – consistent with accumulating evidence that switchgrass genotype impacts microbiome assembly – differential terpenoid accumulation contributes to switchgrass ecotype-specific microbiome composition. An initial in vitro Petri plate-based disc diffusion screen of 18 switchgrass root derived fungal isolates revealed differential responses to upland- and lowland-isolated metabolites. To identify specific fungal growth-modulating metabolites, we tested fractions from root extracts on three ecologically important fungal isolates – Linnemania elongata, Trichoderma sp. and Fusarium sp. Saponins and diterpenoids were identified as the most prominent antifungal metabolites. Finally, analysis of liquid chromatography-purified terpenoids revealed fungal inhibition structure – activity relationships (SAR). Saponin antifungal activity was primarily determined by the number of sugar moieties – saponins glycosylated at a single core position were inhibitory whereas saponins glycosylated at two core positions were inactive. Saponin core hydroxylation and acetylation were also associated with reduced activity. Diterpenoid activity required the presence of an intact furan ring for strong fungal growth inhibition. These results inform future breeding and biotechnology strategies for crop protection with reduced pesticide application.

Antimicrobial Activity and Toxicity of Newly Synthesized 4-[4-(benzylamino)butoxy]-9H-carbazole Derivatives.

One of the main challenges of medicinal chemistry is the search for new substances with antimicrobial potential that could be used in the fight against pathogenic microorganisms. Therefore, the antimicrobial activity of newly synthesized compounds is still being investigated. Carbazole-containing compounds appear to be promising antibacterial, antifungal, and antiviral agents. The aim of this study was to examine the antimicrobial potential and toxicity of newly synthesized isomeric fluorinated 4-[4-(benzylamino)butoxy]-9H-carbazole derivatives. Their antimicrobial activity against bacteria and fungi was tested according to CLSI guidelines. Similarly to previously studied carbazole-containing compounds, the tested derivatives showed the ability to effectively inhibit the growth of Gram-positive bacteria. The addition of carbazole derivatives 2, 4, and 8 at the concentration of 16 µg/mL caused the inhibition of S. aureus growth by over 60%. The MIC value of compounds 2-5 and 7-10 was 32 µg/mL for Staphylococcus strains. Gram-negative strains of E. coli and P. aeruginosa were found to be more resistant to the tested carbazole derivatives. E. coli cells treated with compounds 3 and 8 at a concentration of 64 µg/mL resulted in a greater-than-40% reduction in bacterial growth. In the case of the P. aeruginosa strain, all compounds in the highest concentration that we tested limited growth by 35-42%. Moreover, an over-60% inhibition of fungal growth was observed in the cultures of C. albicans and A. flavus incubated with 64 µg/mL of compounds 2 or 7 and 1 or 4, respectively. The hemolysis of red blood cells after their incubation with the tested carbazole derivatives was in the range of 2-13%. In the case of human fibroblast cells, the toxicity of the tested compounds was higher. Derivative 1, functionalized with fluorine in position 2 and its hydrobromide, was the least toxic. The obtained results indicated the antimicrobial potential of the tested 4-[4-(benzylamino)butoxy]-9H-carbazole derivatives, especially against S. aureus strains; therefore, it is worth further modifying these structures, in order to enhance their activity against pathogenic microorganisms.

Knotwood and Branchwood Polyphenolic Extractives of Silver Fir, Spruce and Douglas Fir and Their Antioxidant, Antifungal and Antibacterial Properties.

The extractive contents of three softwood species largely used in the wood industry, namely Abies alba (Silver fir), Picea abies (spruce) and Pseudotsuga menziesii (Douglas fir), have been determined quantitatively for knots and at different points chosen along their branches, before analysis using high-performance liquid chromatography coupled with Mass Spectrometry (HPLC-MS). The results indicated that branchwood samples located in close proximity to the stem present high contents of extractives similar to those recorded for the knots. HPLC analysis showed quite similar chemical compositions, indicating that first cm of the branches could be considered as an additional source of knotwood. The antibacterial, antifungal and antioxidant activities of knot's extractives have been investigated with the dual objective of better understanding the role of high levels of secondary metabolites present in the knot and evaluating their potential for biorefinery applications. The antioxidant activity study showed that crude extracts of Douglas fir knotwood presented higher radical scavenging activity levels than the extracts of Silver fir and spruce, which presented more or less the same activities. Silver fir and spruce knotwood extracts presented higher antibacterial activity levels than the Douglas fir knotwood extracts did, while Douglas fir knotwood extracts presented more fungal growth inhibition than the spruce and fir knotwood extracts did. The structure-activity relationships indicate that radical scavenging and antifungal activities are associated with a higher relative quantity of flavonoids in the crude extracts, while higher relative quantities of lignans are associated with antibacterial activity.

Fungal inhibition by lactic acid bacteria (LAB) is modulated in vitro by cocoa fermentation-related conditions: towards a biocontrol of fungi in processing cocoa

Fungal growth impair strongly the quality of processed cocoa, leading to low crops value for farmers and manufacturers. The antifungal activity of lactic acid bacteria (LAB) from fermenting cocoa was analyzed and the conditions of fungal inhibition were evaluated. Fungi were isolated from stored fermented and dried cocoa beans on sabouraud plate medium. The results showed that, LAB strongly inhibit fungi isolated from fermented cocoa beans notably Mucors and Aspergilli, with Lactobacillus plantarum inducing the stronger inhibition whereas Leuconostoc mesenteroides produced a weaker inhibition. Acids production assayed by HPLC was found to be not related to antifungal activity, since LAB strains producing strong antifungal activity were not necessarly the best acid producers. Maximum fungal inhibition occured at 35 °C in Lactobacillus plantarum and Leuconostoc mesenteroides but also at 30 °C in Lactobacllus casei. Likewise, a narrow acidic pH range (3.0-4.0) allowed full expression of fungal inhibtion in LAB analyzed that decreased progressively toward pH 7.0 and failed at alkalin pH. However, sucrose even at high content (8%) was found to have no effect on antifungal activity of LAB, but its bioconversion product glucose and fructose decreased this activity when concentrations were set at 6 et 2 %, respectively. All together, the results suggest that, LAB may effectively exert fungal inhibition in a narrow timing of cocoa fermentation, with pulp contained sugars as metabolic regulators of this inhibition. These results may contribute to a better management of LAB as starter culture for an efficient inhibition of fungal growth and prevention of cocoa contamination from mycotoxins.
 Key Words : Antifungal activity ; lactic acid bacteria ; cocoa fermentation ; inhibition variation; pH and temperature ; sugars content.

Effect of Eucalyptus globulus Oil on Growth of The Fungal Pathogen Fusarium oxysporum f. sp. albedinis, The Causal Agent of Date Palm Bayoud Disease in the Laboratory

Noueichi, A., S. Chibani, A. Othmani, M. Boukbach, W. Abdelaziz and R. Mouna. 2023. Effect of Eucalyptus globulus Oil on Growth of The Fungal Pathogen Fusarium oxysporum f. sp. albedinis, The Causal Agent of Date Palm Bayoud Disease in the Laboratory. Arab Journal of Plant Protection, 41(3): 281-284. https://doi.org/10.22268/AJPP-41.3.281284 Fusarium disease of date palm caused by Fusarium oxysporum f. sp. albedinis, commonly known as Bayoud disease, is a serious threat to date palm cultivation in North African countries including Algeria. The inhibitory activity of eucalyptus oil (Eucalyptus globulus) was evaluated in the Plant Biology Laboratory at the University of Constantine, Algeria. The results obtained showed significant inhibition of fungal growth which varied between 17 and 60% based on the concentration used. The pathogen inhibitory effect was mainly due to the presence of monoterpene compounds which have a strong inhibiting property against fungi. The results obtained suggest that Eucalyptus essential oil is potentially a safe and effective alternative to chemical fungicides, but field evaluation for its ability to control date palm Bayoud disease is essential before recommending its use in farmers’ fields. Keywords: Date palm, Fusarium oxysporum f.sp. albedinis, essential oil, Eucalyptus globulus

Phytopathogenic Fungal Growth Inhibition by Actinomycetes Isolated from the Rhizosphere of Cymbopogon citratus (Lemongrass)

The search for natural antimicrobial substances to mitigate the deleterious effects of pathogens is on the increase due to the spread of resistance. In the agricultural sector, the current focus is on natural, eco-friendly, and sustainable approaches to improve crop yield. In this study, sixty actinomycetes isolates belonging to 3 genera; Streptomyces, Nocardia, and Micromonospora, obtained from 30 lemon grass rhizosphere samples, were screened for antifungal activity using three common fungi phytopathogens; Fusarium solani, Aspergillus flavus and Alternaria alternata. Preliminary screening involving the in vitro dual culture assay and the agar well diffusion techniques were employed to investigate the inhibitory activities of actinomycetes isolates and the ethyl acetate extract of their metabolites against the phytopathogens. Results obtained revealed that mycelial extensions in the fungi were significantly inhibited, though, to varying extents. Among the 60 actinomycetes isolates screened, 19 (31.37%) demonstrated significant inhibitory activity against at least one of the three test fungi. Out of the 19 isolates, 5(26.3%) suppressed mycelial growth in all three test fungi with percent mycelial inhibitions ranging from 51.63 – 69.29 %. Also, the crude extracts of the metabolites of these five actinomycetes isolates produced mycelial inhibitions ranging from 75.45 - 89.31 %. Analysis of the crude extracts using gas chromatography, revealed the production of five antifungal compounds which include: Benzylaldehyde,2-nitro-diaminomethylidene hydrazine, [1,2,4] triazolo [1,5] pyrimidine -6-carboxylic acid, 1,2, - benzenediol,3,5-bis(1,1-dimethylethyl), Benzo[h] quinolone,2,4-dimethyl-, and 2,4,6-cycloheptatrien-1-one, 3,5, bis-trimethylsilyl-. Therefore, the antifungal capabilities of these actinomycetes isolates make them efficient, natural, and ecologically friendly alternatives in the control of fungal phytopathogens.

Application of lignin nanoparticles in polybutylene succinate based antifungal packaging for extending the shelf life of bread

The shift of using biodegradable materials for food packaging is becoming a global trend, as environmental consciousness constantly being raised. Enhancing the antimicrobial performance of biodegradable packaging has greatly received much attention for minimizing environmental impacts by reducing food and plastic wastes. This work explored the potential of utilizing an abundant industrial waste lignin as antimicrobial packaging. The effects of lignin nanoparticles (LNPs) incorporated into polybutylene succinate (PBS) composite film, against Aspergillus niger and Penicillium spp., the major microorganisms causing fungal spoilage in bread were investigated. At a low concentration of 0.5 % (w/v), LNPs showed fungal growth inhibition (FGI) in vitro of 51.89 % and 55.94 % against A. niger and Penicillium spp. When incorporated into PBS composite containing 5 % cinnamaldehyde (CIN), 1 % (w/w) LNPs showed stronger antifungal activities against Penicillium spp. than A. niger. Barrier properties and water contact angle were also enhanced with the presence of 1 % (w/w) LNPs in the PBS, but there were no effects on tensile strength, glass transition temperature, and melting temperature (Tm). Bread packed in PBS containing 1 % LNPs + 5 % CIN showed lowest yeast and mold count (YMC) of < 1.0 log CFU g–1, which was the same as the initial count, whereas YMC in other bread samples increased to > 2.0 log CFU g–1 after storage for 14 days at 25 ± 2 °C. Results suggest that LNPs in biodegradable materials such as PBS could help extend the shelf life of bread and possibly be applied to other food products that are susceptible to fungal spoilage.

Citrullus colocynthis (L.) Schrad.: A Promising Pharmaceutical Resource for Multiple Diseases.

Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) is widely distributed in the desert areas of the world. The fruit bodies of C. colocynthis are recognized for their wide range of nutraceutical potential, as well as medicinal and pharmaceutical uses. The plant has been reported for various uses, such as asthma, bronchitis, cancer, colic, common cold, cough, diabetes, dysentery, and jaundice. The fruit has been extensively studied for its biological activities, which include insecticide, antitumor, and antidiabetic effects. Numerous bioactive compounds have been reported in its fruit bodies, such as essential oils, fatty acids, glycosides, alkaloids, and flavonoids. Of these, flavonoids or caffeic acid derivatives are the constituents associated with the inhibition of fungal or bacterial growth, whereas eudesmane sesquiterpenes or sesquiterpene lactones are most active against insects, mites, and nematodes. In this review, the scientific evidence for the biological activity of C. colocynthis against insecticide, cytotoxic, and antidiabetic effects is summarized.

Efficiency Evaluation of Silver Nanoparticles in the Controlling of the Fungi Associated with the Date Palm Offshoots

Recently, Iraq has imported large numbers of tissue culture date palm offshoots from different countries. It is to build new orchards of date palm trees or plant them with the old orchards and some of them in the home's gardens. As a result of the widespread of many symptoms associated with these offshoots, this study was conducted in Basra Governorate, Iraq. To examine the capability of silver nanoparticles in controlling pathogens. The 36 fungi species were isolated from the shoot system of tissue culture date palm offshoots. Alternaria sp. was recorded at a high frequency compared to the Cladosporium spp. and Ulocladium spp. Neodieghtonia phoenicum, Scytalidium lignicola, and Neoscytalidium dimidiatum caused black scorch. Moreover, Phoma costarricensis has been recorded as causing the leaf spot disease. The roots infected by wilt disease have shown three various fungi, Fusarium solani, Fusarium proliferatum, and Fusarium fujikuroi. The study also illustrated that silver nanoparticles possessed a high ability to inhibit fungi growth in the laboratory.

A New Insight into 6-Pentyl-2H-pyran-2-one against Peronophythora litchii via TOR Pathway.

The litchi downy blight disease of litchi caused by Peronophythora litchii accounts for severe losses in the field and during storage. While ample quantitative studies have shown that 6-pentyl-2H-pyran-2-one (6PP) possesses antifungal activities against multiple plant pathogenic fungi, the regulatory mechanisms of 6PP-mediated inhibition of fungal pathogenesis and growth are still unknown. Here, we investigated the potential molecular targets of 6PP in the phytopathogenic oomycetes P. litchii through integrated deployment of RNA-sequencing, functional genetics, and biochemical techniques to investigate the regulatory effects of 6PP against P. litchii. Previously we demonstrated that 6PP exerted significant oomyticidal activities. Also, comparative transcriptomic evaluation of P. litchii strains treated with 6PP Revealed significant up-regulations in the expression profile of TOR pathway-related genes, including PlCytochrome C and the transcription factors PlYY1. We also noticed that 6PP treatment down-regulated putative negative regulatory genes of the TOR pathway, including PlSpm1 and PlrhoH12 in P. litchii. Protein-ligand binding analyses revealed stable affinities between PlYY1, PlCytochrome C, PlSpm1, PlrhoH12 proteins, and the 6PP ligand. Phenotypic characterization of PlYY1 targeted gene deletion strains generated in this study using CRISPR/Cas9 and homologous recombination strategies significantly reduced the vegetative growth, sporangium, encystment, zoospore release, and pathogenicity of P. litchii. These findings suggest that 6PP-mediated activation of PlYY1 expression positively regulates TOR-related responses and significantly influences vegetative growth and the virulence of P. litchii. The current investigations revealed novel targets for 6PP and underscored the potential of deploying 6PP in developing management strategies for controlling the litchi downy blight pathogen.

Trehalase Inhibitor Validamycin May Have Additional Mechanisms of Toxicology against Rhizoctonia cerealis.

Sharp eyespot is a crucial disease affecting cereal plants, such as bread wheat (Triticum aestivum) and barley (Hordeum vulgare), and is primarily caused by the pathogenic fungus Rhizoctonia cerealis. As disease severity has increased, it has become imperative to find an effective and reasonable control strategy. One such strategy is the use of the trehalose analog, validamycin, which has been shown to have a potent inhibitory effect on several trehalases found in both insects and fungi, and is widely used as a fungicide in agriculture. In this study, we demonstrated that 0.5 μg/mL validamycin on PDA plates had an inhibitory effect on R. cerealis strain R0301, but had no significant impact on Fusarium graminearum strain PH-1. Except for its inhibiting the trehalase activity of pathogenic fungi, little is known about its mechanism of action. Six trehalase genes were identified in the genome of R. cerealis, including one neutral trehalase and five acidic trehalase genes. Enzyme activity assays indicated that treatment with 5 μg/mL validamycin significantly reduces trehalase activity, providing evidence that validamycin treatment does indeed affect trehalase, even though the expression levels of most trehalase genes, except Rc17406, were not obviously affected. Transcriptome analysis revealed that treatment with validamycin downregulated genes involved in metabolic processes, ribosome biogenesis, and pathogenicity in the R. cerealis. KEGG pathway analysis further showed that validamycin affected genes related to the MAPK signaling pathway, with a significant decrease in ribosome synthesis and assembly. In conclusion, our results indicated that validamycin not only inhibits trehalose activity, but also affects the ribosome synthesis and MAPK pathways of R. cerealis, leading to the suppression of fungal growth and pesticidal effects. This study provides novel insights into the mechanism of action of validamycin.

Natural Oils Enhance the Topical Delivery of Ketoconazole by Nanoemulgel for Fungal Infections.

Nanoemulgel (NEG) pharmaceutical formulations are gaining popularity because of their ability to serve both as a nanoemulsion and as a gel. These products are well-known for their ease of use, spreadability, controlled release, and ability to hydrate dry skin. Natural essential oils have been shown to promote the cutaneous permeability of topical formulations, enhancing medication safety and efficacy. Herein, we developed NEG for the enhanced permeation of ketoconazole against candidiasis using clove oil (clove-oil-NEG) or eucalyptus oil (eucalyptus-oil-NEG), using the gelling agents carbopol 943 and hydroxypropyl methylcellulose (HPMC). We tested various excipients to increase the solubility of ketoconazole and formulate a nanoemulsion (NE). We measured the NE droplet particle size, shape, entrapment efficiency, and drug release. Furthermore, the physicochemical properties of the optimized nanoemulsion formulation were characterized by techniques such as Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) analysis. The NEs were loaded into gels to form NEGs. NEGs were characterized for drug content, homogeneity, rheology, spreadability, and antifungal activity against Candida albicans, both in vitro and in vivo. Optimized ketoconazole NEG preparations consisted of either 15% clove oil or 20% eucalyptus oil. Droplet sizes in the optimized NEs were <100 nm, and the polydispersity indexes were 0.24 and 0.26. The percentages of ketoconazole released after 24 h from the clove-oil-NEG and eucalyptus-oil-NEGs were 91 ± 4.5 and 89 ± 7%, respectively. Scanning electron microscopy (SEM) showed that the NEGs had a smooth, uniform, and consistent shape and internal structural organization. The drug contents in the clove-oil-NEG and eucalyptus-oil-NEG were 98.5 ± 2.2 and 98.8 ± 3.4%, respectively. Permeation values of ketoconazole from clove-oil-NEG and eucalyptus-oil-NEG were 117 ± 7 and 108.34 ± 6 μg cm-2, respectively. The ketoconazole NEG formulations also had higher levels of fungal growth inhibition than a marketed formulation. Finally, in vivo studies showed that the NEGs do not irritate the skin. Ketoconazole NEG with either 15% clove oil or 20% eucalyptus oil is stable with better efficacy than ketoconazole alone due to excellent dispersion, drug dissolution, and permeability and thus might be recommended for the effective and safe treatment of candidiasis.

Vernonia amygdalina Extract Loaded Microspheres for Controlling Phytophthora palmivora

The adverse effects of modern fungicide consumption have caused many issues in the agroecosystem. Hence, under sustainable agriculture concepts, it is important to research alternatives to the currently used fungicide. The use of secondary metabolite-containing herbal extracts for treating plant diseases has become the latest trend in sustainable and green agriculture. However, the poor solubility and volatile nature of many compounds cause practical issues when using them in the field. Hence, bioactive compound delivery through nano- or micro-particles has become a successful technique to improve the solubility and delivery of secondary metabolites to targeted sites. In the current study, the ethyl acetate (EtOAc) extract from dried leaves of Vernonia amygdalina was tested against Phytophthora palmivora isolated from Durian (Durio zibethinus) root rot. Further, the potential of enhancing the effect of V. amygdalina EtOAc treatment through microspheres loaded with V. amygdalina EtOAc extract was also investigated. The microspheres encapsulated with Eudragit® E were synthesized under different electrospray conditions to obtain the microspheres with the highest efficacy. The poison media assays evaluated the fungal growth inhibition efficiency of the V. amygdalina EtOAc crude extract and the synthesized microspheres. The study reveals that the V. amygdalina EtOAc extract has the potential to suppress the growth of P. palmivora. Interestingly, the synthesized microspheres showed immense growth inhibition in P. palmivora, with a 61.10 µg/mL decrease in ED50 compared to the direct usage of V. amygdalina EtOAc extract.

In Vitro Evaluation of Some Endophytic Bacillus to Potentially Inhibit Grape and Grapevine Fungal Pathogens

Romania has a long history of grapevine culturing and winemaking. However, like any agricultural sector, viticulture faces devastating biological threats. Fungi responsible for grapevine trunk diseases (GTDs) and grape spoilage lead to considerable yield losses and a decline in grapevine quality. In the actual context, many countries, including Romania, have reoriented their approaches to minimize chemical inputs, which have been proven to be toxic and to have negative impacts on the environment, and to replace them with sustainable biocontrol strategies for the wine-growing sector. Within biocontrol strategies, Bacillus spp. is a well-known plant-protective bacteria with antifungal properties. Within this paper, six endophytic bacteria from various plant sources were studied. The bacterial strains were identified as B. pumilus, B. subtilis, and B. velezensis by sequencing their 16S rDNA region. Regardless of the in vitro test methods (using living bacterial cells, bacterial-cell-free supernatant (CFS), and volatile active compounds (VOCs)), B. velezensis strains revealed strong and broad antifungal activity against grape and grapevine fungal pathogens such as Aspergillus spp., Botrytis cinerea, Penicillium expansum, Diplodia seriata, Eutypa lata, Fusarium spp., Clonostachys rosea, Neofusicoccum parvum, and Stereum hirsutum. The functional antifungal genes encoding for difficidin, fengycin, iturins, macrolactin, and mycosubtilin were molecularly detected, which could support the proven antifungal activity of the endophytic strains. Lytic enzymes involved in fungal growth inhibition, such as chitinase, cellulase, and proteases, were also revealed to be produced by some of these bacterial strains. Various other in vitro tests, such as phosphate and phytate solubilization, phytohormone synthesis, the production of enzymes involved in the polyamine biosynthetic pathway, and pH as well as temperature tolerance tests were carried out to reveal the plant-beneficial potential of these bacterial strains. These results revealed that the B. velezensis strains, especially BAHs1, are the most suitable endophytes for grapevine biologic control, which could lead to the future development of sustainable management strategies.

Kosakonia cowanii Ch1 Isolated from Mexican Chili Powder Reveals Growth Inhibition of Phytopathogenic Fungi.

Kosakonia cowanii strain Ch1 was isolated from Mexican chili powder, and the genome was sequenced. The genome was 4,765,544 bp in length, with an average G + C content of 56.22%, and a plasmid (pCh1) of 128,063 bp with an average G + C content of 52.50%. A phylogenetic analysis revealed a close relation with pathogenic strains; nevertheless, some virulence-related genes were absent, and this genetic characteristic may explain the fact that K. cowanii Ch1 behaved as a non-pathogenic strain when infection assays were performed on the leaves and fruits of Capsicum annuum L. Surprisingly, we observed that this bacterial strain had the ability to spread throughout serrano pepper seeds. Furthermore, K. cowanii Ch1 was evaluated for the production of volatile organic compounds (VOCs) against fungal pathogens, and the results showed that Alternaria alternata and Sclerotium rolfsii were inhibited in a radial mycelial growth assay by a mean rate of 70% and 64%, while Fusarium oxysporum was inhibited by only approximately 10%. Based on the headspace solid-phase microextraction combined with the gas chromatography mass spectrometry (HS-SPME-GC-MS), 67 potential VOCs were identified during the fermentation of K. cowanii Ch1 in TSA medium. From these VOCs, nine main compounds were identified based on relative peak area: dodecanoic acid; 3-hydroxy ethanol; 1-butanol-3-methyl; acetaldehyde; butanoic acid, butyl ester; cyclodecane; 2-butanone, 3-hydroxy; disulfide, dimethyl and pyrazine-2,5-dimethyl. Our findings show the potential of K. cowanii Ch1 for the biocontrol of fungal pathogens through VOCs production and reveal additional abilities and metabolic features as beneficial bacterial specie.

Effect of green Fe2O3 nanoparticles in controlling Fusarium fruit rot disease of loquat in Pakistan.

The subtropical fruit known as the loquat is prized for both its flavour and its health benefits. The perishable nature of loquat makes it vulnerable to several biotic and abiotic stressors. During the previous growing season (March-April 2021), loquat in Islamabad showed signs of fruit rot. Loquat fruits bearing fruit rot symptoms were collected, and the pathogen that was causing the disease isolated and identified using its morphology, microscopic visualisation, and rRNA sequence. The pathogen that was isolated was identified as Fusarium oxysporum. Green synthesized metallic iron oxide nanoparticles (Fe2O3 NPs) were employed to treat fruit rot disease. Iron oxide nanoparticles were synthesized using a leaf extract of the Calotropis procera. Characterization of NPs was performed by different modern techniques. Fourier transform infrared spectroscopy (FTIR) determined the existence of stabilizing and reducing compounds like phenol, carbonyl compounds, and nitro compounds, on the surface of Fe2O3 NPs. X-ray diffraction (XRD) explained the crystalline nature and average size (~49 nm) of Fe2O3 NPs. Energy dispersive X-ray (EDX) exhibited Fe and O peaks, and scanning electron microscopy (SEM) confirmed the smaller size and spherical shape of Fe2O3 NPs. Following both in vitro and in vivo approaches, the antifungal potential of Fe2O3 NPs was determined, at different concentrations. The results of both in vitro and in vivo analyses depicted that the maximum fungal growth inhibition was observed at concentration of 1.0 mg/mL of Fe2O3 NPs. Successful mycelial growth inhibition and significantly reduced disease incidence suggest the future application of Fe2O3 NPs as bio fungicides to control fruit rot disease of loquat.