Plant Pathogenic Fungi Fusarium Oxysporum Research Articles

Synthesis, antifungal, antibacterial activity, and computational evaluations of some novel coumarin-1,2,4-triazole hybrid compounds

Effective plant pathogen control presents an important challenge. Pesticide resistance and associated health and environmental problems demonstrate the need for novel, safe active ingredients for plant protection. Since both coumarins and 1,2,4-triazoles show pesticidal activity, in this study, we evaluated the antimicrobial activity of coumarin-1,2,4-triazole hybrids against plant pathogenic fungi (Fusarium oxysporum, Fusarium culmorum, Macrophomina phaseolina and Sclerotinia sclerotiorum), bacterial plant pathogens (Pseudomonas syringae and Rhodococcus fascians), and beneficial bacteria (Bacillus mycoides and Bradyrhizobium japonicum). Coumarin-1,2,4-triazoles inhibited the growth of S. sclerotiorum and F. oxysporum, while no antibacterial effect on either pathogens or soil-beneficial bacteria was observed. A quantitative structure–activity relationship models for antifungal activities on S. sclerotiorum and F. oxysporum, developed using Dragon descriptors, can explain 79% and 77% of the compounds inhibitory activity, respectively. According to molecular docking, title compounds are potential sterol 14α-demethylase inhibitors, with 7-((5-mercapto-4-(p-tolyl)-4H-1,2,4-triazol-3-yl)methoxy)-4-methyl-2H-chromen-2-one as the promising candidate for further research in plant protection.

Segmental duplications drive the evolution of accessory regions in a major crop pathogen.

Many pathogens evolved compartmentalized genomes with conserved core and variable accessory regions (ARs) that carry effector genes mediating virulence. The fungal plant pathogen Fusarium oxysporum has such ARs, often spanning entire chromosomes. The presence of specific ARs influences the host range, and horizontal transfer of ARs can modify the pathogenicity of the receiving strain. However, how these ARs evolve in strains that infect the same host remains largely unknown. We defined the pan-genome of 69 diverse F. oxysporum strains that cause Fusarium wilt of banana, a significant constraint to global banana production, and analyzed the diversity and evolution of the ARs. Accessory regions in F. oxysporum strains infecting the same banana cultivar are highly diverse, and we could not identify any shared genomic regions and in planta-induced effectors. We demonstrate that segmental duplications drive the evolution of ARs. Furthermore, we show that recent segmental duplications specifically in accessory chromosomes cause the expansion of ARs in F. oxysporum. Taken together, we conclude that extensive recent duplications drive the evolution of ARs in F. oxysporum, which contribute to the evolution of virulence.

A novel isatin Schiff based cerium complex: synthesis, characterization, antimicrobial activity and molecular docking studies

In this work, a novel isatin-Schiff base L2 had been synthesized through a simple reaction between isatin and 2-amino-5-methylthio-1,3,4-thiadiazole. The produced Schiff base L2 was then subjected to a hydrothermal reaction with cerium chloride to produce the cerium (III)-Schiff base complex C2. Several spectroscopic methods, including mass spectra, FT-IR, elemental analysis, UV–vis, 13C-NMR, 1H-NMR, Thermogravimetric Analysis, HR-TEM, and FE-SEM/EDX, were used to completely characterize the produced L2 and C2. A computer simulation was performed using the MOE software program to find out the probable biological resistance of studied compounds against the proteins in some types of bacteria or fungi. To investigate the interaction between the ligand and its complex, we conducted molecular docking simulations using the molecular operating environment (MOE). The docking simulation findings revealed that the complex displayed greater efficacy and demonstrated a stronger affinity for Avr2 effector protein from the fungal plant pathogen Fusarium oxysporum (code 5OD4) than the original ligand. The antibacterial activity of the ligand and its Ce3+ complex were applied in vitro tests against different microorganism. The study showed that the complex was found to be more effective than the ligand.

Determination of Antifungal Activity of Leaf Extracts from Hypericum ssp. Against Plant Pathogenic Fungi Fusarium oxysporum and Alternaria Alternata

In this study, the antifungal activity of ethanol extracts of three plant species of Hypericum perforatum, Hypericum scabrum and Hypericum origanifolium were evaluated for against two plant pathogenic fungal species of Fusarium oxysporum and Alternaria alternata.The antifungal activities of Hypericum ssp. extracts (3, 15, 45, 80, 120, 200, 240, 300 ppm) were tested against fungi. Ethanol 30% as control; Commercial fungicide (1 μg/mL) was used as a positive control. All Hypericum ssp. plant extracts were effective in different rates against the fungi depending on the doses. In addition, IC50 values of the three selected plant Hypericum ssp. leaf extract against pathogenic fungus F.oxysporum and A. alternata were determined with of probit analysis. In terms of the IC50 values, the antifungal activity of H. perforatum plant exract against F.oxysporum (122.525 μg/mL) > A.alternata (108.484 μg/mL). On the other hand, IC50 values of H. scabrum against A.alternata (126.390 μg/mL) > F.oxysporum (113.714 μg/mL). Moreover, the IC50 value of H. origanifolium against two pathogenic fungi was calculated as F.oxysporum (159.931 μg/mL) > A.alternata (55.759 μg/mL). Results showed that H.origanifolium has the best fungicidal activity, with IC50 value of 55.759 μg/mL against A.alternata and H.scabrum 113.717 μg/mL against F.oxysporum. However, the highest concentrations (300 ppm) caused completely inhibition in the both fungi mycelial growth followed by lower concentrations of plant extracts. A. alternata were the sensitive fungal species, while the F. oxysporum were a more resistant to the Hypericum ssp. extracts. Based on the antifungal activity tests, these plants extracts this may have effective as the new natural fungicide protecting crops against fungal diseases.

Transposon-based identification of genes involved in the rimocidin biosynthesis in Streptomyces rimosus M527.

The transposon mutagenesis strategy has been employed to generate random insertion mutants and analyze the correlation between genes and secondary metabolites in the genus Streptomyces. In this study, our primary objective was to identify an unknown gene involved in rimocidin biosynthesis and elucidate its role in rimocidin production in Streptomyces rimosus M527. To achieve this, we established a random mutant library of S. rimosus M527 using a Tn5 transposon-mediated random mutagenesis strategy. Among the 137 isolated mutants, M527-G10 and M527-W5 exhibited the most significant variations in antagonistic activity against the plant pathogenic fungus Fusarium oxysporum f. sp. cucumerinum. Specifically, M527-G10 displayed a 72.93% reduction, while M527-W5 showed a 49.8% increase in rimocidin production compared to the wild-type (WT) strain S. rimosus M527. Subsequently, we employed a plasmid rescue strategy to identify the insertion loci of the transposon in the genomes of mutants M527-G10 and M527-W5, revealing a response regulator transcription factor (rrt) and a hypothetical protein (hyp), respectively. The roles of rrt and hyp in rimocidin biosynthesis were determined through gene deletion, overexpression in the WT strain, and complemented expression in the transposon mutants. Notably, the gene-deletion mutants M527-ΔRRT and M527-ΔHYP exhibited similar behavior in rimocidin production compared to the corresponding transposon mutants M527-G10 and M527-W5, suggesting that transposon insertions in genes rrt and hyp led to alterations in rimocidin production. Furthermore, both gene deletion and overexpression of rrt and hyp had no discernible effects on cell growth. These results reveal that genes rrt and hyp have positive and negative impacts on rimocidin production in S. rimosus M527, respectively.

Evaluation of some bioactive compounds of <i>Azadirachta indica</i> extracts and its application as safe fungicide against different plant pathogenic fungi

Extracts of leaves, seeds and twigs of Azadirachta indica was carried out using Soxhlet extraction technique. These extracts were subjected to percent yield, in vitro phytochemical screening and antifungal activities (minimum fungicidal concentration (MFC), minimum inhibitory concentration (MIC), zone of inhibition and spore germination assay) against plant pathogenic fungi Cladosporium fulvum, Colletotrichum coccodes, Fusarium oxysporum and Rhizoctonia solani. The Soxhlet extractive solvents were methanol, ethanol, chloroform, ethyl acetate and n–hexane. The maximum extractive yield were calculated in ethanol leaves (26±1.5%), methanol leaves (22±01%), n–hexane seeds (32±0.8%) and ethanol seeds (24±01%), while twigs calculated minimum extractive yield. The phytochemicals screening findings confirmed the occurrence of terpenoids, phenols, flavonoids, glycosides, alkaloids, tannins and saponins. The antifungal activities observed that leaves and seeds extracts of neem might cause the inhibition of mycelium and spore germination of tested fungi, though the antifungal activities rate of under study fungal strains diverse with dissimilar concentration and nature of extracts. However the entire concentrations of extract and crude extract especially the methanol and ethanol extracts of neem seeds and leaves reduce the plant pathogenic fungi growth at noteworthy rate. It was concluded from our results that neem leaves and seeds extracts were effectual as antifungal agents against the entire under study fungal strains however the most sensitive fungi were Rhizoctonia solani and Fusarium oxysporum. The findings acquired from this study revealed that chemical constituents from neem seeds and leaves may be formulated as latent agrochemical fungicides.

Assessing long-distance atmospheric transport of soilborne plant pathogens

Pathogenic fungi are a leading cause of crop disease and primarily spread through microscopic, durable spores adapted differentially for both persistence and dispersal via soil, animals, water, and/or the atmosphere. Computational Earth system models and air pollution models have been used to simulate atmospheric spore transport for aerial-dispersal-adapted (airborne) rust diseases, but the importance of atmospheric spore transport for soil-dispersal-adapted (soilborne) diseases remains unknown. While a few existing simulation studies have focused on intracontinental dispersion, transoceanic and intercontinental atmospheric transport of soilborne spores entrained in agricultural dust aerosols is understudied and may contribute to disease spread. This study adapts the Community Atmosphere Model, the atmospheric component of the Community Earth System Model, to simulate the global transport of the plant pathogenic soilborne fungus Fusarium oxysporum (F. oxy). Our sensitivity study assesses the model’s accuracy in long-distance aerosol transport and the impact of deposition rate on simulated long-distance spore transport in Summer 2020 during a major dust transport event from Northern Sub-Saharan Africa to the Caribbean and southeastern United States (U.S.). We find that decreasing wet and dry deposition rates by an order of magnitude improves representation of long-distance, trans-Atlantic dust transport. Simulations also suggest that a small number of spores can survive trans-Atlantic transport to be deposited in agricultural zones. This number is dependent on source spore parameterization, which we improved through a literature search to yield a global map of F. oxy spore distribution in source agricultural soils. Using this map and aerosol transport modeling, we show how potentially viable spore numbers in the atmosphere decrease with distance traveled and offer a novel danger index for modeled viable spore deposition in agricultural zones. Our work finds that intercontinental transport of viable spores to cropland is greatest between Eurasia, North Africa, and Sub-Saharan Africa, suggesting that future observational studies should concentrate on these regions.

Antifungal activity of Terminalia chebula extract against wilt fungi Fusarium oxysporum an important plant pathogen

Terminalia chebula, a deciduous plant, endogenous to India has medicinal value. Its fruits are known for its cure to many ailments in human beings. This study is to test the biological activity of these compounds tested against plant pathogenic fungi Fusarium oxysporum which cause wilt in economically important crops. Wilt is a devastating disease which destroys the infected plant and cause economic loss to farmers. Panama disease in bananas is a type of wilt disease which is very prevalent in India. This fungi has broad host range from tomato, cotton etc. Outbreak reported in many parts of India. Standard culture of Fusarium oxysporum ITCC -6246, Fusarium oxysporum f. sp. ciceri ITCC 3636 and Fusarium oxysporum f. sp. lycopersici MTCC 10270 were used to detect the potential chemical compound in dried fruit by macro-dilution. Each organic solvent (Water, Ethanol, Chloroform, Benzene) has different extraction capacity based on the polarity of chemical compound in plants. These chemical compounds extensively studied for their antioxidant property and preliminary screening of chemical compound constituents in all extract. Mycelium growth inhibition tested on solid medium and zone of inhibition measured in mm diameter. Spores of Fusarium sp. present in soil for many months in dormant form. Under suitable climatic conditions this will germinate and cause infection in plants. Rate of spore germination inhibition in liquid medium measured and calculated for every solvent extract. Rate of inhibition was calculated and analysed statistically by t test. The efficient solvent extract determined for bulk extraction of biologically active compound from seeds.

Antifungal activity of myco-synthesized bimetallic ZnO-CuO nanoparticles against fungal plant pathogen Fusarium oxysporum

Abstract Fusarium species are considered one of the most destructing plant pathogens. In the current study, bimetallic zinc oxide-copper oxide nanoparticles (ZnO-CuO NPs) were myco-synthesized using Aspergillus fumigatus for controlling Fusarium oxysporum growth. Aspergillus fumigatus was isolated from soil and identified morphologically and genetically. The myco-synthesized ZnO-CuO NPs were characterized using UV-Vis, DLS, HR-TEM, SEM, and XRD analyses. HR-TEM characterization method indicated that, the biosynthesized bimetallic ZnO-CuO NPs appeared as semi-spherical with the average diameter specified as 54.18 ± 1.9 nm. The DLS method described the characteristic particle size diffusion and was calculated as 85.52 nm, 90.85 nm, and 92.85 nm for ZnO NPs, CuO NPs, and ZnO-CuO NPs, respectively. Additionally, the SEM image of ZnO-CuO NPs displays basic NP surface character and the exterior impression was apparent. The biosynthesized ZnO-CuO NPs were separated naturally as spherical particles connected within the fungal filtrate, which displays as illuminated NPs fused and capped with the fungal filtrate. Antifungal activity of bimetallic ZnO-CuO NPs was evaluated against F. oxysporum. Results revealed that bimetallic ZnO-CuO NPs exhibited promising antifungal activity toward F. oxysporum where inhibition zone at 1000 µg/ml was 22.8 ± 0.76 mm, and MIC was 125 µg/ml. Moreover, growth inhibition percentages of F. oxysporum at different concentrations of bimetallic ZnO-CuO NPs 1000, 500, 250, and 125 µg/ml were 88.9, 65.5, 41.1, and 8.9% respectively, where the highest inhibition was 88.9% at concentration 1000 µg/ml, while the lowest inhibition was 8.9% at concentration 125 µg/ml. In TEM ultrastructure results, the treated F. oxysporum with ZnO-CuO NPs, a clear destruction was found in all cell contents and disintegration of the cell wall as well as destruction of the plasma membrane. Also, the nucleus appeared as small size and damaged shape and the chromatin materials distributed with several dark stained bodies in cytoplasm. In conclusion, bimetallic ZnO-CuO NPs were successfully myco-synthesized using A. fumigatus, where it had promising antifungal activity against F. oxysporum.

Comparative bioactive compounds and antifungal potential evaluation of Mentha longifolia (L.) Hudson (Lamiaceae) extracts against plant pathogenic fungi

The present study was design to evaluate the Mentha longifolia stem, flower and leaves infusion, decoction and hydroalcoholic extracts to determine the bioactive molecules and antifungal activities by zone of inhibition technique, Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were assay by broth dilution technique and spore germination assay using Light Compound Microscope against plant pathogenic fungi (Fusarium oxysporum, Aspergillus parasiticus, Rhizoctonia solani and Alternaria alternata). The Mentha longifolia phytochemicals were found in the range flavonoids 3.8 - 2.4%, saponins were 5.6-3.4%, alkaloids 0.7-0.1% and total phenolic were 40-15 mg Gallic acid/g. The maximum zone of inhibition 23±1 mm and 22±1 mm were found by hydroalcoholic leaves extract against Fusarium oxysporum and Aspergillus parasiticus respectively. The MIC range of hydroalcoholic were 12.5-100 mg/mL, infusion were 25-100 mg/mL and decoction were 25-200 mg/mL. While MFC range of hydroalcoholic were 25-200 mg/mL, infusion were 50- 200 mg/mL and decoction were 50-200 mg/mL. Spore germination assay reaveled that increse in the extract concenetration decrese the spore germination. The results revealed that Mentha longifolia chemical composition might be build up as latent bio- fungicides against plant pathogenic fungi.

Metatranscriptome-based strategy reveals the existence of novel mycoviruses in the plant pathogenic fungus Fusarium oxysporum f. sp. cubense.

Fusarium oxysporum f. sp. cubense (Foc) is a devastating plant pathogen that caused a great financial loss in the banana's source area. Metatranscriptomic analysis was used to determine the diversity of mycoviruses in 246 isolates of F. oxysporum f. sp. cubense. Partial or nearly complete genomes of 20 mycoviruses were obtained by BLASTp analysis of RNA sequences using the NCBI database. These 20 viruses were grouped into five distinct lineages, namely Botourmiaviridae, Endornaviridae, Mitoviridae, Mymonaviridae, Partitiviridae, and two non-classified mycoviruses lineages. To date, there is no report of the presence of mycoviruses in this pathogen. In this study, we demonstrate the presence of mycoviruses isolated from Foc. These findings enhance our overall knowledge of viral diversity and taxonomy in Foc. Further characterization of these mycoviruses is warranted, especially in terms of exploring these novel mycoviruses for innovative biocontrol of banana Fusarium wilt disease.

Isolation, Identification and Cultivation of Ganoderma spp. and Evaluation of Their Efficiency in Inhibiting Plant Pathogenic Fungi Fusarium oxysporum and Alternaria tenuissima

Fruit bodies of three Ganoderma isolates coded by Has.AA-6, Has.AA-7 and Has.AA-8 were collected from the trunks of Poplar, Sidr and Apricot trees, respectively, from some districts in Salah al-Din Governorate. It was phenotypically diagnosed to the genus level depending on the shapes, colors and sizes of the fruit bodies as well as the internal tissues and basidiospores. Molecular diagnoses to the species level was carried out depending on the percentage of identical 5.8S rRNA gene sequences with strains of fungi in the World Genetic Bank at the NCBI. Ganoderma isolates identified as G. applanatum Has.AA-6, G. lucidum Has.AA-7 and G. resinaceum Has.AA-8, and recorded in the World Genetic Bank at the NCBI under the accession number ON834523.1, ON834541.1 and ON834527.1, respectively. The results of cultivation of Ganoderma spp. showed a superiority of the biological efficiency of the corn cobs supplemented with wheat bran, which were 27.73, 31.27, 31.64 and 32.07%, compared to unsupplemented this medium, as the biological efficiency reached 26.18, 26.67, 27.21, 27.22, and 27.22% for G. lucidum, G. applanatum, G. resinaceum and G. resinaceum 1049 respectively. The role of the filtrate, mycelium biomass and fruit bodies of Ganoderma spp. against the pathogenic fungi F. oxysporum and A. tenuissima was studied, the results showed that the extracts of all Ganoderma spp. have a significant superiority in inhibiting the growth of both pathogenic fungi compared to the control treatment, the alcoholic extract of G. resinaceum fruit bodies recorded the highest inhibition of the F. oxysporum and A. tenuissima in which the colonies diameters reached 3.21 and 2.4cm, respectively, while G. lucidum gave the lowest colony diameter of F. oxysporum and A. tenuissima, which reached 2.61 and 2.25 cm, respectively, compared to with a diameter of 8.5 cm for colonies of both pathogenic fungi in the control.

Improvement of antagonism and fungicides tolerance in Trichoderma harzianum and T.viride local isolates by Ultra-Violet irradiation

Among 22 Iraqi Trichoderma harzianum and T.viride isolates, T3,T5,D5,S1 and S6 related to T. harzianum showed a higher antagonistic activity against the plant pathogenic fungi Fusarium oxysporum and Rhizoctonia solani. These isolates were selected for improvement their biocontrol activity by usi
 ng uv-irradiation. The optimum exposure time to ultraviolet irradiation is 30 min, in which, the percentage of kill was 98-99% .After UV-irradiation treatment (Quartz lamps 30W at 240-280 nm, peak 254nm, distance from the source was 20 cm), antagonistic capability against R. solani and F. oxysporum was improved in mutants MT3,MT5,MS1 and MS6, in which antagonistic reaction score were 3.6,3.9,3.2 and 3.6 against F. oxysporum and 3.7,4,3.4 and 4 against R. solani compared to 3.2, 2.8, 2.6 and 2.8 against F. oxysporum and 2.7, 2.9,3.1 and 3 against R. solani in the wild types T3, T5, S1 and S6,respectively. The growth of T. harzianum isolates (estimated as colony diameter) was significantly increased in all T. harzianum mutants except MT3 and MD5 mutants, CMCase activity was increased from 13.2, 16.2, 10 and 15.8 U/ml / mg protein in the wild isolates T3, T5, S1 and S6 to 18.6, 20.3, 17.7 and 22.5 U/ml / mg protein in the mutants MT3, MT5, MS1 and MS6, respectively. Chitinase activity was also increased in these mutants to 88.4,132.3,86.1 and 136.7 U/ml / mg protein, compared to 82.7, 93.2, 74.5 and 103.2 U/ml / mg protein in their wild, respectively. As comparison between wild types and mutants, the maximum growth was 5.2 and 4.8 cm (as colonies diameters) by MT5 in present of 25% of the recommended field rate of Topsin and Benomyl, compared to 3.3 and 2.2 cm in the wild type T5, respectively, followed by MS6,in which, the maximum growth in this mutant was 4.8 and 4.2 cm in the same concentration of these two fungicides, compared to 3.4 and 2.5 cm in the wild type S6, respectively. According to these results, the mutants MT5 and MS6 developed from UV-irradiation treatment, showed as promising T. harzianum mutants through their antagonistic activity (at mycoparasitism level) , fast growth, higher CMCase and chitinase activity and growth in 25% of the recommended field rate of Elsa , 25 and 50% of the recommended field rate of Diathen and Mizab and all concentrations of Topsin and Benomyl with complete inhibition of pathogenic fungi F. oxysporum and R. solani.

Sesquiterpenoids with Phytotoxic and Antifungal Activities from a Pathogenic Fungus Aspergillus alabamensis.

Five new carotane sesquiterpenoids (asperalacids A-E (1-5)), one new tricyclic sesquiterpenoid (4-hydroxy-5(6)-dihydroterrecyclic acid A (6)), and two known analogues (7-8) were obtained from a seagrass-derived fungus Aspergillus alabamensis, which was speculated to be a phytopathogenic fungus, isolated from the necrotic leaves of Enhalus acoroides. The structures of 1-6 were established by a combination of spectroscopic methods, including comprehensive NMR analysis, mass spectrometry, conformational analysis, NMR computational methods, and ECD calculations. Compound 4, with higher inhibitory activity on wheat (Triticum aestivum L.) root and shoot elongation than the positive control terbutryn, a broad-spectrum systemic herbicide, is a new natural plant growth inhibitor. Compound 5, belonging to the rare glycosylated sesquiterpenoid class, represents the first example of glycosylated carotane sesquiterpenoid whose sugar moiety was identified as α-d-glucose. Compounds 1-4 and 6 displayed weak to potent antimicrobial activity against the plant pathogenic fungi Fusarium oxysporum, Fusarium graminearum, and Penicillium italicum and the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus.

Meta-analysis of fungal plant pathogen Fusarium oxysporum infection-related gene profiles using transcriptome datasets.

Fusarium oxysporum is a serious soil-borne fungal pathogen that affects the production of many economically important crops worldwide. Recent reports suggest that this fungus is becoming the dominant species in soil and could become the main infectious fungus in the future. However, the infection mechanisms employed by F. oxysporum are poorly understood. In the present study, using a network meta-analysis technique and public transcriptome datasets for different F. oxysporum and plant interactions, we aimed to explore the common molecular infection strategy used by this fungus and to identify vital genes involved in this process. Principle component analysis showed that all the fungal culture samples from different datasets were clustered together, and were clearly separated from the infection samples, suggesting the feasibility of an integrated analysis of heterogeneous datasets. A total of 335 common differentially expressed genes (DEGs) were identified among these samples, of which 262 were upregulated and 73 were downregulated significantly across the datasets. The most enriched functional categories of the common DEGs were carbohydrate metabolism, amino acid metabolism, and lipid metabolism. Nine co-expression modules were identified, and two modules, the turquoise module and the blue module, correlated positively and negatively with all the infection processes, respectively. Co-expression networks were constructed for these two modules and hub genes were identified and validated. Our results comprise a cross fungal-host interaction resource, highlighting the use of a network biology approach to gain molecular insights.

Evaluation of essential oil and hydrolate from a new hyssop variety (Hyssopus officinalis L.)

The main objective of this study was to evaluate the quality of essential oil (EO) and hydrolate (HY) obtained from a new Romanian variety of hyssop (Hyssopus officinalis L., Lamiaceae family), namely ‘Cătălin’. The chemical composition and the concentration of the compounds was established by gas chromatography coupled to mass spectrometry (GC/MS). The main constituents identified in hyssop EO and HY were cis-pinocamphone (34.63% and 67.00%), trans-pinocamphone (11.72% and 14.58%), thujenol (1.39% and 6.05%). The evaluation of the antioxidant capacity was performed by three methods (DPPH, ABTS and FRAP), EO proving a higher oxidizing activity compared to HY one. The antimicrobial activity of the essential oil was evaluated in vitro, in order to detect its ability to inhibit G- phytopathogenic bacteria (Pseudomonas syringae) and plant pathogenic fungi (Fusarium oxysporum). Eugenol, linalool and estragole standards were used as reference volatile compounds. Regarding Pseudomonas syringae (LMG5090) bacterium, assays showed that hyssop oil does not inhibit its growth. Estragole and eugenol showed pronounced antibacterial activity in all tested concentrations, both in the first 24 hours of incubation and after 3 days. Linalool instead has bacteriostatic activity only at high concentrations (50% and 100%), an inhibitory activity that is maintained only in the first 24 hours of incubation. The results obtained against Fusarium oxysporum reveal that the EO tested has no fungicidal activity but only fungistatic, and it is able to delay mycelial growth and the degree of inhibition depending on the concentration used.

WITHDRAWN: Acetate derivative of Morita –Baylis-Hillman adducts (MBH): A powerful antifungal

In previous work, a new class of synthesized bioactive compounds of Morita –Baylis-Hillman adducts (MBH) showed an antioxidant and anti melanogensis activity. Accordingly, in the present work the relationship between antifungal activity and the responsible chemical function of MBH adducts and their derivatives (alcohols, acetates, phosphonates and hydrazono phosphonates) was investigated against plant pathogenic fungi Aspergillus niger, Fusarium oxysporum, Penicillium occitanis, Trichoderma reesei, Stachybotrys microspora, Fusarium solani, Trichoderma parceramosum, fusarium aethiopicum, Alternaria alternata and Aspergillus flavus using the agar diffusion method. Results showed acetates displayed varying degrees of antifungal activity against several fungi tested, while just one alcohol compound showed lower activity. The derivative with five carbon (2g) was the most powerful with an inhibitor growth zone diameter of 4.75÷0.21, 6.1±0.14, 4.35±0.21, 3.9±0.14, 4.54± 0.11, 3.55±0.07, 3±0, 3.2± 0.2, 5.36 ± 0.26 and 5.06± 0.5cm against; F. oxysporum, T. parceramosum, S. microspora, T. reesei, F. solani, P. occitanis, A. niger, F. aethiopicum, A. alternate and A. flavus respectively. Compared to the positive control the nystatin, most of the tested compounds exhibited moderate to strong inhibitory effects. The antifungal activity depended on the radical group. The novelty is that these adducts are evaluated for the first time for their antifungal effect. Antifungal activity is in general of linear or cyclic molecules coupled to six carbons. Here we show that the simple acetate six membered carbons are the most efficient molecule

Design, Synthesis, and Antifungal Activity of 4-Amino Coumarin Based Derivatives.

A series of 30 succinate dehydrogenase inhibitors (SDHIs) of 4-amino coumarin-based derivatives were designed and synthesized. According to the analysis of fungicidal activity in vitro, most of the compounds expressed broad-spectrum antifungal activity against four plant pathogenic fungi (Alternaria alternata, Alternaria solani, Fusarium oxysporum, and Botrytis cinerea) using the mycelium growth inhibition method. The results showed that compounds 3n with the group of 2-ene-3-methyl-butyl and 4e with the group of 2-bromo-1-oxo-hexyl displayed excellent activity against Alternaria alternata and Alternaria solani, with EC50 values of 92~145 μg/mL. Molecular docking showed that the inhibitor 3n was completely locked into the cavity of SDH, forming a conventional hydrogen bond interacting with the amino acid residue TYR58. The present work indicates that these derivatives would serve as novel potential fungicides targeting SDH.

Effects of Coumarinyl Schiff Bases against Phytopathogenic Fungi, the Soil-Beneficial Bacteria and Entomopathogenic Nematodes: Deeper Insight into the Mechanism of Action.

Coumarin derivatives have been reported as strong antifungal agents against various phytopathogenic fungi. In this study, inhibitory effects of nine coumarinyl Schiff bases were evaluated against the plant pathogenic fungi (Fusarium oxysporum f. sp. lycopersici, Fusarium culmorum, Macrophomina phaseolina and Sclerotinia sclerotiourum). The compounds were demonstrated to be efficient antifungal agents against Macrophomina phaseolina. The results of molecular docking on the six enzymes related to the antifungal activity suggested that the tested compounds act against plant pathogenic fungi, inhibiting plant cell-wall-degrading enzymes such as endoglucanase I and pectinase. Neither compound exhibited inhibitory effects against two beneficial bacteria (Bacillus mycoides and Bradyrhizobium japonicum) and two entomopathogenic nematodes. However, compound 9 was lethal (46.25%) for nematode Heterorhabditis bacteriophora and showed an inhibitory effect against acetylcholinesterase (AChE) (31.45%), confirming the relationship between these two activities. Calculated toxicity and the pesticide-likeness study showed that compound 9 was the least lipophilic compound with the highest aquatic toxicity. A molecular docking study showed that compounds 9 and 8 bind directly to the active site of AChE. Coumarinyl Schiff bases are promising active components of plant protection products, safe for the environment, human health, and nontarget organisms.

Enhanced antifungal and antioxidant activities of new chitosan derivatives modified with Schiff base bearing benzenoid/heterocyclic moieties

In this work, chitosan derivatives modified with Schiff base bearing benzenoid/heterocyclic moieties were successfully prepared via amidation reaction. Specific structural characterization was implemented using FTIR and 1H NMR, and the DS of chitosan derivatives were quantitatively calculated by ratio of hydrogen proton integral. Meanwhile, the antifungal activity against two common plant pathogenic fungi (Fusarium oxysporum f. sp. cubense and Glomerella cingulata) was assayed in vitro by hyphal measurement, and data proved that the introduction of functional groups including benzene/heterocyclic compounds and Schiff base groups greatly enhanced the antifungal activity. Besides, the antioxidant efficiency was investigated in vitro, and all chitosan derivatives exhibited significantly increased antioxidant activity. Specially, the scavenging effect of 2SATCS was 96.62% at 1.6 mg/mL, which was close to the positive control VC (98.84%). These results indicated that chitosan derivatives with enhanced antifungal and antioxidant activities could serve as potential biomaterial for antifungal and antioxidant applications.