Phytopathogenic Fungi Research Articles

Nitrogen-Metabolism Inhibitor NmrA Regulates Conidial Production, Melanin Synthesis, and Virulence in Phytopathogenic Fungus Verticillium dahliae.

NmrA homologs have been reported as conserved regulators of nitrogen metabolite repression in various fungi. Here, we identified an NmrA homolog in Verticillium dahliae and reported its functions in nitrogen utilization, growth and development, and pathogenesis. VdNmrA interacts with the V. dahliae AreA protein and regulates the expression of a typical NMR target, the formamidase gene. VdNmrA deletion mutants exhibited significantly slower colony growth on media with Gln or Arg. Furthermore, VdNmrA deletion impaired hyphal growth, spore production, hyperosmotic stress tolerance, and melanin biosynthesis. Fewer reactive oxygen species were produced in VdNmrA mutants, and the NADPH oxidase genes noxA and noxB showed lowered expression levels compared with the wild type. VdNmrA mutants exhibited reduced virulence on cotton and Arabidopsis compared with wild-type strains. Our results indicated that VdNmrA functioned as a nitrogen metabolite repression repressor and played important roles in nutrient utilization, fungal development, stress tolerance, and pathogenicity in V. dahliae.

Chemical Constituents and Antifungal Properties of Piper ceanothifolium Kunth Against Phytopathogens Associated with Cocoa Crops

In this study, the antifungal potential of chemical constituents of Piper ceanothifolium Kunth was determined against three phytopathogenic fungi associated with the cocoa crop. The methodology included the phytochemical study of the inflorescences of P. ceanothifolium, the synthesis of a chroman-4-one type derivative and the evaluation of the antifungal activity against Moniliophthora roreri, Fusarium solani, and Lasiodiplodia theobromae. The phytochemical study led to the isolation and identification of two new hydroquinones (1 and 5), together with three known compounds (hydroquinones 2 and 3, and chromene 4). The synthesis of a new chromone 6 obtained from 2 through an oxa-Michael type intramolecular cyclization is also reported. All compounds showed strong antifungal activity, with 6 (IC50 of 16.9 µM) standing out for its action against F. solani, while prenylated hydroquinones 1 (30.4 µM) and 2 (60.0 µM) were the most active against M. roreri and L. theobromae, respectively. The results of this research represent the first report of the chemical composition and antifungal properties for P. ceanotifolium, suggesting its potential use as a control method against M. roreri, F. solani, and L. theobromae.

Synthesis, Antifungal Activity and In Silico Study of Novel Quinoline Thioether Derivatives Inspired by Natural Quinoline.

Inspired by natural quinoline, a series of novel quinoline derivatives containing thioether groups were designed and synthesized. All target compounds were characterized using 1H NMR, 13C NMR, and HRMS. Their antifungal activities were evaluated in vitro against ten phytopathogenic fungi. Among the synthesized compounds, 3l (4-(allylthio)-8-fluoro-2,3-dimethylquinoline) exhibited significant antifungal activity, with inhibition rates exceeding 80% against Sclerotinia sclerotiorum and Physalospora piricola at 50 μg/mL. The structure-activity relationship (SAR) analysis revealed that the presence of an alkene group in the thioether side chain enhanced antifungal activity. Molecular docking studies with Pyricularia oryzae dihydroorotate dehydrogenase (PoDHODH) indicated that 3l forms a hydrogen bond with His89, while density functional theory (DFT) calculations provided insights into the electronic properties of the compounds. Additionally, ADMET predictions suggested that 3l has favorable pharmacokinetic properties, similar to the commercial fungicide tebufloquin. These findings highlight the potential of 3l as a lead compound for further development of novel antifungal agents.

Isolation, Phytochemical Characterization, and Inhibitory Potential of Essential Oil From Citrus hystrix DC. Fruit Peels Against Foodborne and Phytopathogenic Microbes.

Plant-based essential oils (EOs) are currently targeted sources because of their non-toxic, bioactivity, and safety of non-targeted organisms. Various volatile components such as terpenoids, phenolics, and alkaloids make it compatible with broad-spectrum applications. In the current study, EO from Citrus hystrix DC. fruit peels were isolated. The gas chromatography-mass spectrometry analysis of the EO has confirmed the presence of various volatile components, in which 3-propylphenol has a maximum peak area percentage of 50.28%. The functional determination through Fourier-transform infrared spectroscopy detected the presence of aldehydic C-H and aldehydic carbonyl C═O group. Antioxidant capability also exhibited 55.61% 2,2-diphenyl-1-picrylhydrazyl scavenging activity with an IC50 value of 84.46µg/mL. The antibacterial property analysis of EO against food spoilage-related bacteria through agar well diffusion methods reveals more effectiveness against gram-positive bacteria with 25µg/mL minimum inhibitory concentration values. The antifungal activity analysis of EO against phytopathogenic fungi through agar dilution methods shows efficacy in controlling Fusarium oxysporum with the inhibitive percentage of 79.15% at the concentration of 250µg/mL and Penicillium choerospondiatis with an inhibition percentage of 100% at the concentration of 250µg/mL. This EO exhibits high potency for controlling food-spoilage-related bacteria and can be quite effective for controlling postharvest mold infection caused by phytopathogens.

Direct and Volatile Potential Applications of Essential Oils for Post-Harvest Fungi Control.

Around one third of food production is lost globally, significantly impacting food security, primarily due to post-harvest deterioration from phytopathogenic fungi. This study aimed to assess the antifungal properties of essential oils (EOs) from Syzygium aromaticum, Origanum vulgare L., Cymbopogon martini, Cymbopogon citratus, Mentha spicata, and Mentha piperita against three fungi affecting tropical fruits: Lasiodiplodia theobromae, Alternaria alternata, and Fusarium solani. The antifungal efficacy was evaluated using direct contact and volatilization methods, determining the minimum inhibitory concentration (MIC) needed to completely inhibit fungal growth. Scanning Electron Microscopy (SEM) was employed to observe the effects of EOs on fungal cells. Among the tested oils, O. vulgare showed the most promise, with MIC values ranging from 40 to 200 µL/L for volatile exposure and 125 to 500 µL/L for direct contact. The results indicated that vapor exposure was more effective, requiring lower concentrations for fungal control. Thus, these EOs, particularly that of O. vulgare, present a viable alternative to synthetic fungicides for managing post-harvest fungal infections in tropical fruits, promoting sustainable agricultural practices.

Antifungal Polyacetylenic Deoxyglycosides Isolated from Endophytic Fungus Xylaria sp. VDL4 Associated with Vaccinium dunalianum

One novel C10 polyacetylene rhamnoside, 4,6,8-decatriyne-1-O-α-L-rhamnopyranoside, named xylariside A (1), together with two novel C10 polyacetylene quinovopyranosides, 4,6,8-decatriyne-1-O-α-D-quinovopyranoside, xylariside B (2), and 8E-decaene-4,6-diyne-1-O-α-D-quinovopyranoside, xylariside C (3), were obtained from the solid fermentation of Xylaria sp. VDL4, an endophytic fungus isolated from Vaccinium dunalianum wight (Ericaceae). Their chemical structures were elucidated through a combination of spectroscopic techniques. The antifungal activities of these compounds were evaluated in vitro against four phytopathogenic fungi (Fusarium oxysporum, Botrytis cinerea, Phytophthora capsici, and Fusarium solani). Compound 2 demonstrated significant antifungal activities, with minimum inhibitory concentration (MIC) values ranging from 3.91 to 7.81 μg/mL. Compound 2’s effectiveness levels were similar to those of the reference drugs thiabendazole and carbendazim (each MIC = 0.98−15.62 μg/mL). Xylariside B (2) was further evaluated against B. cinerea in vivo. It exhibited remarkable efficacy in both the prevention and treatment of tomato and strawberry gray mold. Molecular docking studies confirmed the antifungal mechanism of compound 2 by revealing its binding interactions with key enzyme targets in B. cinerea, thereby supporting the observed in vitro and in vivo results. Additionally, compound 2 showed effective inhibition of α-glucosidase, with IC50 values of 5.27 ± 0.0125 μg/mL.

Molecular characterization of a novel non-segmented double-stranded RNA mycovirus isolated from the phytopathogenic fungus Lasiodiplodia pseudotheobromae.

In this study, we isolated a novel mycovirus from Lasiodiplodia pseudotheobromae strain YY-1, which we named "Lasiodiplodia pseudotheobromae mycovirus 1" (LpMyV1). The complete genome of LpMyV1 is 2877 bp in length and contains two non-overlapping open reading frames (ORF1 and ORF2). ORF1 encodes a putative protein of 316 amino acids with a molecular weight of 34.1 kDa that shares similarity with the coat proteins of several mycoviruses. ORF2 encodes a protein of 561 amino acids with a molecular weight of 63.2 kDa that contains a conserved RNA-dependent RNA polymerase (RdRp) domain. BLASTp results showed that the RdRp of LpMyV1 shares the highest similarity with those of non-segmented dsRNA viruses. A multiple sequence alignment and phylogenetic analysis indicated that LpMyV1 is a new member of the proposed genus "Unirnavirus". This is the first report of a mycovirus from L. pseudotheobromae.

Sustainable Management of Major Fungal Phytopathogens in Sorghum (Sorghum bicolor L.) for Food Security: A Comprehensive Review

Sorghum (Sorghum bicolor L.) is a globally important energy and food crop that is becoming increasingly integral to food security and the environment. However, its production is significantly hampered by various fungal phytopathogens that affect its yield and quality. This review aimed to provide a comprehensive overview of the major fungal phytopathogens affecting sorghum, their impact, current management strategies, and potential future directions. The major diseases covered include anthracnose, grain mold complex, charcoal rot, downy mildew, and rust, with an emphasis on their pathogenesis, symptomatology, and overall economic, social, and environmental impacts. From the initial use of fungicides to the shift to biocontrol, crop rotation, intercropping, and modern tactics of breeding resistant cultivars against mentioned diseases are discussed. In addition, this review explores the future of disease management, with a particular focus on the role of technology, including digital agriculture, predictive modeling, remote sensing, and IoT devices, in early warning, detection, and disease management. It also provide key policy recommendations to support farmers and advance research on disease management, thus emphasizing the need for increased investment in research, strengthening extension services, facilitating access to necessary inputs, and implementing effective regulatory policies. The review concluded that although fungal phytopathogens pose significant challenges, a combined effort of technology, research, innovative disease management, and effective policies can significantly mitigate these issues, enhance the resilience of sorghum production to facilitate global food security issues.

Bacillus velezensis CNPMS-22 as biocontrol agent of pathogenic fungi and plant growth promoter.

Bacillus velezensis is a ubiquitous bacterium with potent antifungal activity and a plant growth promoter. This study investigated the potential of B. velezensis CNPMS-22 as a biocontrol agent against phytopathogenic fungi under diverse experimental conditions and its potential as a plant growth promoter. Genome sequencing and analysis revealed putative genes involved in these traits. This research performed in vitro experiments to evaluate the CNPMS-22 antagonistic activity against 10 phytopathogenic fungi using dual culture in plate (DCP) and inverted sealed plate assay (ISP). Greenhouse and field tests evaluated the ability of CNPMS-22 to control Fusarium verticillioides in maize plants in vivo. The CNPMS-22 genome was sequenced using the Illumina HiSeq 4,000 platform, and genomic analysis also included manual procedures to identify genes of interest accurately. CNPMS-22 showed antifungal activity in vitro against all fungi tested, with notable reductions in mycelial growth in both DCP and ISP experiments. In the ISP, volatile organic compounds (VOCs) produced by CNPMS-22 also altered the mycelium coloration of some fungi. Scanning electron microscopy revealed morphological alterations in the hyphae of F. verticillioides in contact with CNPMS-22, including twisted, wrinkled, and ruptured hyphae. Eight cluster candidates for synthesizing non-ribosomal lipopeptides and ribosomal genes for extracellular lytic enzymes, biofilm, VOCs, and other secondary metabolites with antifungal activity and plant growth promoters were identified by genomic analysis. The greenhouse and field experiments showed that seed treatment with CNPMS-22 reduced Fusarium symptoms in plants and increased maize productivity. Our findings highlight the CNPMS-22's potential as bioinoculant for fungal disease control and plant growth with valuable implications for a sustainable crop productivity.

Impact of Oxalic Acid Consumption and pH on the In Vitro Biological Control of Oxalogenic Phytopathogen Sclerotinia sclerotiorum

The phytopathogenic fungus Sclerotinia sclerotiorum has a wide host range and causes significant economic losses in crops worldwide. This pathogen uses oxalic acid as a virulence factor; for this reason, the degradation of this organic acid by oxalotrophic bacteria has been proposed as a biological control approach. However, previous studies on the potential role of oxalotrophy in biocontrol did not investigate the differential effect of oxalic acid consumption and the subsequent pH alkalinisation on fungal growth. In this study, confrontation experiments on different media using a wild-type (WT) strain of S. sclerotiorum and an oxalate-deficient mutant (strain Δoah) with the soil oxalotrophic bacteria Cupriavidus necator and Cupriavidus oxalaticus showed the combined effect of media composition on oxalic acid production, pH, and fungal growth control. Oxalotrophic bacteria were able to control S. sclerotiorum only in the medium in which oxalic acid was produced. However, the deficient Δoah mutant was also controlled, indicating that the consumption of oxalic acid is not the sole mechanism of biocontrol. WT S. sclerotiorum acidified the medium when inoculated alone, while for both fungi, the pH of the medium changed from neutral to alkaline in the presence of bacteria. Therefore, medium alkalinisation independent of oxalotrophy contributes to fungal growth control.

Phenolic acid compounds isolated from Zanthoxylum armatum inhibit gray mold by disrupting cellular structures, affecting energy metabolism, and inducing oxidative stress of Botrytis cinerea

Phenolic acid compounds isolated from Zanthoxylum armatum inhibit gray mold by disrupting cellular structures, affecting energy metabolism, and inducing oxidative stress of Botrytis cinerea

Design, Synthesis, and Antifungal Activity of Melatonin Derivatives Containing a (Thio)Semicarbazide Group.

Melatonin is a natural hormone that has functions such as circadian rhythm regulation, neuroregulation and cardiac protection, as well as antifungal activity. In this study, two series of melatonin derivatives containing a semicarbazide or a thiosemicarbazide group were designed and synthesized. The antifungal screening results indicated that compound III-9 exhibited a broad antifungal spectrum against six phytopathogenic fungi at 50 µg/mL, with over 60% growth inhibition, and this is highlighted by its inhibition rates of 80.8% and 87.2% against Botrytis cinerea and Rhioctorzia solani, respectively, which was superior to the commercial fungicide Osthole. It also showed moderate antifungal activity in vivo against Cucumber botrytis cinerea, Sclerotinia sclerotiorum, and Phytophthora capsica at 200 µg/mL. And the scanning electron microscope (SEM), molecular docking, and enzymatic activity results provided insights into the potential mechanisms underlying the antifungal activity of these derivatives, which might target succinate dehydrogenase (SDH). Study of structure-activity relationships (SAR) and pesticide-likeness prediction offered valuable guidance for the future structural optimization of melatonin derivatives.

Three new compounds of Umbelopsis dimorpha VDG10, a dominant endophytic fungus from Vaccinium dunalianum Wight.

Three new compounds of Umbelopsis dimorpha VDG10, a dominant endophytic fungus from Vaccinium dunalianum Wight.

Unveiling Fusarium falciforme: Genome sequencing of a Novel wilt causing pathogen in subabul (Leucaena leucocephala L.) in India.

Unveiling Fusarium falciforme: Genome sequencing of a Novel wilt causing pathogen in subabul (Leucaena leucocephala L.) in India.

Understanding cargo sorting and interactive effects of membrane vesicles in fungal phytopathogens: Current knowledge and research gaps

Understanding cargo sorting and interactive effects of membrane vesicles in fungal phytopathogens: Current knowledge and research gaps

Combination of atmospheric and room temperature plasma and ribosome engineering techniques to enhance the antifungal activity of Bacillus megaterium L2 against Sclerotium rolfsii.

Sclerotium rolfsii is an extremely destructive phytopathogenic fungus that causes significant economic losses. Biocontrol strategies utilizing antagonistic microorganisms present a promising alternative for controlling plant pathogens. Bacillus megaterium L2 has been identified as a potential microbial biocontrol agent in our previous study; however, its efficacy in controlling pathogens has yet to meet current demands. This study aims to enhance the antifungal activity of strain L2 against S. rolfsii R-67 through a two-round mutagenesis strategy and to preliminarily investigate the mutagenesis mechanism of the high antifungal activity mutant. We obtained mutant Dr-77 with the strongest antifungal activity against R-67, and its cell-free supernatant significantly reduced the infection potential of R-67 to Amorphophallus konjac corms, which may be attributed to the antimicrobial compound phenylacetic acid (PAA), and PAA content in Dr-77 (5.78 mg/mL) was 28.90 times higher than original strain L2. This compound exhibited strong antifungal ability against R-67, with a half maximal effective concentration (EC50) value of 0.475 mg/mL, significantly inhibiting mycelial growth and destroying the ultrastructure of R-67 at EC50 value. Notably, PAA also exhibited broad-spectrum antifungal activity against six phytopathogens at EC50 value. Moreover, genome analysis revealed nine different gene mutations, including those involved in PAA biosynthesis, and the activities of prephenate dehydratase (PheA) and phenylacetaldehyde dehydrogenase (ALDH) in PAA biosynthesis pathway were significantly increased. These results suggest that the elevated PAA content is a primary factor contributing to the enhanced antifungal activity of Dr-77, and that this mutagenesis strategy offers valuable guidance for the breeding of functional microbial resources. © 2024 Society of Chemical Industry.

Zinc-chitosan nanocomposites as guardians against the dreaded phytopathogenic fungus Macrophomina phaseolina in Vigna radiata L.

Zinc-chitosan nanocomposites as guardians against the dreaded phytopathogenic fungus Macrophomina phaseolina in Vigna radiata L.

Diversity of copper-containing nanoparticles and their influence on plant growth and development.

Diversity of copper-containing nanoparticles and their influence on plant growth and development.

Design, synthesis, crystal structure, fungicidal activity, and mechanism of action of novel thiazole-based hydrazide derivatives containing the 4-aminoquinazoline moiety.

Design, synthesis, crystal structure, fungicidal activity, and mechanism of action of novel thiazole-based hydrazide derivatives containing the 4-aminoquinazoline moiety.

Multi-omic investigation identifies key antifungal biochemistry during fermentation of a Streptomyces biological control agent.

Multi-omic investigation identifies key antifungal biochemistry during fermentation of a Streptomyces biological control agent.