Fungal Pathogens Research Articles

Determination of the prevalence of fungi associated with amaranth cultivation in the locality of Kombé, Republic of Congo

Amaranth is a nutrient-rich leafy vegetable. Phytopathogenic fungi are causing major losses in amaranth crop production in the Kombé area. The detection of these phytopathogenic fungi can play an important role. The aim of this study is to assess the abundance of endophytic and saprophytic fungi associated with amaranth cultivation in Brazzaville, with a view to recommending biological control of fungal diseases. The prevalence of fungi associated with amaranth began with a survey, then continued in the laboratory. During the survey, 15 amaranth and soil samples were then collected separately in different stomacher bags, labelled and shipped to the laboratory where they were stored in a refrigerator at 4°C for four (4) weeks for analysis. In the laboratory, endophytic and saprophytic fungi were isolated using the fresh-state inoculation method for endophytic fungi and the suspension-dilution method for saprophytic fungi. The isolated strains were identified by determining their macroscopic and microscopic characteristics. The phytosanitary survey revealed that the most dominant symptom on amaranth plants in Kombé was wilting (42.86%). The results obtained from the distribution of endophyte isolates by colour indicate the presence of 5 isolates of unidentified endophytic fungi obtained from the leaf organ. Through isolation and microscopic analysis of soil saprophytes, six genera of fungi were identified: Botrytis cineara, Rhizoporus sp, Penicillium sp, Mucor sp, Scedospirium sp and Curvularia sp.

Toxicity potential of a pyraclostrobin-based fungicide in plant and green microalgae models

ABSTRACT Pyraclostrobin-based fungicides play an effective role in controlling fungal diseases and are extensively used in agriculture. However, there is concern regarding the potential adverse effects attributed to exposure to these fungicides on non-target organisms and consequent influence exerted on ecosystem functioning. Thus, it is essential to conduct studies with model organisms to determine the impacts of these fungicides on different groups of living organisms. The aim of this study was to examine the ecotoxicity associated with exposure to commercial fungicides containing pyraclostrobin. The focus of the analysis involved germination and initial development of seedlings of 4 plant models (Lactuca sativa, Raphanus sativus, Pennisetum glaucum and Triticum aestivum), in addition to determining the population growth rate and total carbohydrate content in microalga Raphidocelis subcapitata. The fungicide pyraclostrobin adversely influenced growth and development of the tested plants, indicating a toxic effect. The fungicide exerted a significant impact on the initial development of seedlings of all model species examined with T. aestivum plants displaying the greatest susceptibility to pyraclostrobin. Plants of this species exhibited inhibitory effects on both aerial parts and roots when treated with a concentration of 4.75 mg/L pyraclostrobin. In addition, the green microalga R. subcapitata was also significantly affected by the fungicide, especially at relatively high concentrations as evidenced by a reduction in total carbohydrate content. This commercial fungicide demonstrated potential phytotoxicity for the tested plant models and was also considered toxic to the selected microalgae, indicating an ecotoxic effect that might affect other organisms in aquatic environments.

β-Cyclodextrin-optimized supramolecular nanovesicles enhance the droplet/foliage interface interactions and inhibition of succinate dehydrogenase (SDH) for efficient treatment of fungal diseases

BackgroundPlant fungal diseases present a major challenge to global agricultural production. Despite extensive efforts to develop fungicides, particularly succinate dehydrogenase inhibitors (SDHIs), their effectiveness is often limited by poor retention of fungicide droplets on hydrophobic leaves. The off-target losses and unintended release cause fungal resistance and severe environmental pollution.ResultsTo update the structure of existing SDHIs and synchronously realize the efficient utilization, we have employed a sophisticated supramolecular strategy to optimize a structurally novel SDH inhibitor (AoH25), creating an innovative supramolecular SDH fungicide (AoH25@β-CD), driven by the host-guest recognition principle between AoH25 and β-cyclodextrin (β-CD). Intriguingly, AoH25@β-CD self-assembles into biocompatible supramolecular nanovesicles, which reinforce the droplet/foliage (liquid-solid) interface interaction and the effective wetting and retention on leaf surfaces, setting the foundation for enhancing fungicide utilization. Mechanistic studies revealed that AoH25@β-CD exhibited significantly higher inhibition of SDH (IC50 = 1.56 µM) compared to fluopyram (IC50 = 244.41 µM) and AoH25 alone (IC50 = 2.29 µM). Additionally, AoH25@β-CD increased the permeability of cell membranes in Botryosphaeria dothidea, facilitating better penetration of active ingredients into pathogenic cells. Further experimental outcomes confirmed that AoH25@β-CD was 88.5% effective against kiwifruit soft rot at a low-dose of 100 µg mL-1, outperforming commercial fungicides such as fluopyram (52.4%) and azoxystrobin (65.4%). Moreover, AoH25@β-CD showed broad-spectrum bioactivity against oilseed rape sclerotinia, achieving an efficacy of 87.2%, outstripping those of fluopyram (48.7%) and azoxystrobin (76.7%).ConclusionThis innovative approach addresses key challenges related to fungicide deposition and resistance, improving the bioavailability of agricultural chemicals. The findings highlight AoH25@β-CD as a novel supramolecular SDH inhibitor, demonstrating its potential as an efficient and sustainable solution for plant disease management.Graphical

Study of the Effects of Bioactive Compounds of Cyanobacterium Desmonostoc alborizicum on Pathogenic Fungi of Wheat

Study of the Effects of Bioactive Compounds of Cyanobacterium Desmonostoc alborizicum on Pathogenic Fungi of Wheat

A Review on Molecular Mechanism of Plant Immunity against Fungal Pathogens

The molecular mechanisms of plant immunity, with a particular focus on how plants defend themselves against fungal pathogens. Plant immunity is a complex, multi-layered system involving pattern-triggered immunity (PTI) and effector-triggered immunity (ETI), which together form a robust defense against a wide array of pathogens. Advances in genomics and transcriptomics have significantly enhanced our understanding of these immune mechanisms by identifying key resistance (R) genes and uncovering the transcriptional networks that regulate immune responses. Proteomics and metabolomics further elucidate the functional aspects of immunity, revealing how proteins and metabolites are mobilized during pathogen attack. The advent of gene editing technologies, particularly CRISPR-Cas9, has opened new avenues for enhancing plant immunity by enabling precise modifications of genes associated with disease resistance. The ever-evolving nature of fungal pathogens, driven by genetic diversity and environmental changes, poses ongoing challenges. Emerging pathogens and the breakdown of existing resistance in crops underscore the need for durable resistance strategies, which can be achieved through the pyramiding of multiple R genes, susceptibility gene knockouts, and the harnessing of beneficial plant microbiomes. As climate change exacerbates the spread and virulence of fungal pathogens, developing climate-resilient crops that can withstand both abiotic stresses and pathogen pressures is becoming increasingly important. Future research should prioritize understanding the molecular dynamics of plant-pathogen interactions, leveraging new technologies for crop improvement, and fostering interdisciplinary collaboration to address these challenges. Ultimately, translating these scientific advances into practical applications will be crucial for ensuring global food security and sustainable agricultural systems in the face of mounting environmental and biological threats.

A survey of cranberry fruit rots in commercial production beds in Oregon and Washington

IntroductionFungal fruit rots are a perennial threat to the production of cranberries. Eleven genera of fungi have been reported to cause cranberry rot in the field and/or during cold storage. Oregon and Washington rank fourth and fifth in the production of cranberries in the USA, but much of the research on cranberry fruit rots has been conducted in Wisconsin, New Jersey, and Massachusetts.ObjectiveThe primary objective of this project was to describe the current composition of cranberry fruit rot complex in Oregon and Washington.MethodsA survey of fungal fruit rot pathogens was conducted over four years in commercial cranberry farms located in the Pacific Ocean coastal zone in Oregon and Washington.ResultsYield, rot incidence, and fungal pathogens isolated varied year-to-year. Pathogens isolated frequently from field-rotted cranberries included the cranberry fruit rot genera described in other cranberry production regions of the USA, such as Colletotrichum, Coleophoma, and Physalospora. Neofabraea actinidiae, a recently described cranberry fruit rot, was isolated consistently from field-rotted cranberries from beds with specific fungicide usage patterns. N. actinidiae also was one of the more common storage rot pathogens in this region, alongside other well-established storage rots like Coleophoma and black rots caused by Allantophomopsis cytisporea, A. lycopodina, and Strasseria geniculata.ConclusionsThese findings may have important implications for Washington cranberry production because a large proportion of the crop is dry-harvested, placed in cold storage, and then sold as fresh cranberries. Climatic differences among the cranberry production areas across the United States may affect the disease incidence and prevalence of different genera of cranberry fruit rot pathogens, as summer months in Oregon and Washington are often much cooler and dryer than in Wisconsin and east coast states and may account for differing presence of various cranberry fruit rot fungi.

A review of pathogenic airborne fungi and bacteria: unveiling occurrence, sources, and profound human health implication

Airborne fungi and bacteria have been extensively studied by researchers due to their significant effects on human health. We provided an overview of the distribution and sources of airborne pathogenic microbes, and a detailed description of the detrimental effects that these microorganisms cause to human health in both outdoor and indoor environments. By analyzing the large body of literature published in this field, we offered valuable insights into how airborne microbes influence our well-being. The findings highlight the harmful consequences associated with the exposure to airborne fungi and bacteria in a variety of natural and human-mediated environments. Certain demographic groups, including children and the elderly, immunocompromised individuals, and various categories of workers are particularly exposed and vulnerable to the detrimental effect on health of air microbial pollution. A number of studies performed up to date consistently identified Alternaria, Cladosporium, Penicillium, Aspergillus, and Fusarium as the predominant fungal genera in various indoor and outdoor environments. Among bacteria, Bacillus, Streptococcus, Micrococcus, Enterococcus, and Pseudomonas emerged as the dominant genera in air samples collected from numerous environments. All these findings contributed to expanding our knowledge on airborne microbe distribution, emphasizing the crucial need for further research and increased public awareness. Collectively, these efforts may play a vital role in safeguarding human health in the face of risks posed by airborne microbial contaminants.

Green Synthesis of Chitosan-coated Tin Dioxide Nanoparticles Using Moringa oleifera Flower Extract Against Breast Cancer via the Caspase-dependent Apoptotic Pathway

Background and Purpose In the present work, chitosan is furnished with tin dioxide (CsSnO2) nanoparticles (NPs) synthesized using the green route using Moringa oleifera ( M. oleifera) flower extract. Methods These preparation methods are low-cost, easily reproducible, nontoxic, and eco-friendly. X-ray diffraction (XRD), dynamic light scattering (DLS), field emission scanning electron microscope (FESEM), energy dispersive X-ray, Fourier-transform infrared spectroscopy (FT-IR), and photoluminescence (PL) analysis were used to learn more about the CsSnO2 NPs. The antibacterial property of CsSnO2 NPs was assessed by the disc diffusion method against various pathogens. The MTT assay was done to assess the cytotoxicity of CsSnO2 NPs in MCF-7 cells. The expressions of the apoptotic proteins were examined using assay kits. Results XRD results demonstrated that the formulated CsSnO2 NPs exhibit a tetragonal structure. From the FT-IR spectra, the Sn–O stretching peak was observed at 579 cm–1. A FESEM image shows that the CsSnO2 NPs were formed into a spherical structure. Surface defects, such as tin and oxygen vacancies, are visible in the PL spectra, and the average particle size of CsSnO2 NPs is 32 nm. Thus, surface defects are essential parameters for biocidal properties. The antimicrobial property of CsSnO2 NPs and amoxicillin was investigated against bacteria and human fungal pathogens. CsSnO2 NPs exhibit similar antimicrobial properties as compared to amoxicillin. Also, the dosage of CsSnO2 NPs elevated their antimicrobial activity. The anticancer property of the green-synthesized CsSnO2 NPs against MCF-7 cells was further analyzed to study their ability to cytotoxicity and apoptosis induction, like caspase-3, -8, and -9 activation. Conclusion The study’s outcome revealed that the green synthesized CsSnO2 NPs are an outstanding candidate for cancer therapy.

Enzymatic Hydrolysis of Resorcylic Acid Lactones by an Aeromicrobium sp.

Zearalenone and radicicol are resorcylic acid lactones produced by numerous plant pathogenic fungi. Zearalenone is a non-steroidal estrogen mimic that can cause serious reproductive issues in livestock that consume contaminated feed. Radicicol is a potent inhibitor of the molecular chaperone Hsp90, which, in plants, has an important role in coordinating the host’s immune response during infection. Here, we describe the identification and characterization of a soil-borne strain of the Gram-positive bacterium Aeromicrobium sp. capable of hydrolyzing the macrolide ring of resorcylic acid lactones, including zearalenone and radicicol. Proteomic analysis of biochemically enriched fractions from the isolated and cultured bacterium identified an α/β-hydrolase responsible for this activity. A recombinantly expressed and purified form of the hydrolase (termed RALH) was active against both zearalenone and radicicol. Interpretation of high-resolution mass spectrometry and NMR data confirmed the structures of the enzymatic products as the previously reported non-toxic metabolite hydrolyzed zearalenone and hydrolyzed radicicol. Hydrolyzed radicicol was demonstrated to no longer inhibit the ATPase activity of the Saccharomyces cerevisiae Hsp90 homolog in vitro. Enzymatic degradation of resorcylic acid lactones will enable insight into their biological functions.

Identification and Antagonistic Potential of Bacillus atrophaeus against Wheat Crown Rot Caused by Fusarium pseudograminearum

Fusarium pseudograminearum (Fpg) is a significant pathogen responsible for fusarium crown rot (FCR) in wheat (Triticum aestivum L.), a disease with devastating impacts on crop yield. The utilization of biocontrol bacteria to combat fungal diseases in plants is a cost-effective, eco-friendly, and sustainable strategy. In this trial, an endophytic bacterial species, designated as SW, was isolated from the roots of wheat. The strain exhibited potent antagonistic effects against Fpg and reduced the FCR disease severity index by 76.07 ± 0.33% in a greenhouse pot trial. Here, 106 colony-forming units (CFUs)/mL of the SW strain was determined to be the minimum dose required to exhibit the antagonism against Fpg. The strain was identified as Bacillus atrophaeus using genome sequencing and comparison with type strains in the NCBI database. Whole-genome sequencing analysis revealed that SW harbors genes for siderophores, antifungal metabolites, and antibiotics, which are key contributors to its antagonistic activity. Additionally, the strain’s ability to utilize various carbon and nitrogen sources, successfully colonize wheat root tissues as an endophyte, and form biofilms are critical attributes for promoting plant growth. In summary, these findings demonstrate the ability of Bacillus atrophaeus to control FCR disease in wheat in a sustainable agricultural setting.

Monitoring of plant diseases caused by Fusarium commune and Rhizoctonia solani in bok choy using hyperspectral remote sensing and machine learning.

Local vegetable production is susceptible to various fungal pathogens, the most common and lethal of which are Fusarium commune and Rhizoctonia solani. Early detection of these pathogens is challenging, and by the time visual symptoms appear, the pathogens may have already spread extensively, causing massive damage to the production. In this study, we explored the use of hyperspectral data for early detection of diseases caused by F. commune or R. solani in bok choy Brassica rapa subsp. chinensis by collecting hyperspectral data from healthy plants and plants inoculated with either fungal pathogen in a controlled experimental set-up. Based on the collected data, we employed various tree-based, distribution-based, geometric, neural networks and ensemble learning algorithms to train detection models. Among the trained models, Multi-Layer Perceptron (MLP) models performed the best with overall accuracy reaching 95.9 ± 0.26%. MLP models could differentiate between healthy and infected plants with 99% precision after 1 day of infection, and distinguish between different fungal pathogens with 99% precision after 2 days. During this period, no visible symptoms of fungal infection could be observed. Further analysis into trained MLP models and general reflectance profiles of plants also revealed a high correlation of the spectral regions 445-460, 560-595, 606-620 and 719-728 nm with fungal infection in bok choy plants. Our findings highlight the potential of hyperspectral imaging as a highly precise early detection tool for fungal diseases in plants. © 2024 Society of Chemical Industry.

Effect of mowing timing and clipping collection practices on azoxystrobin distribution, persistence, and efficacy

AbstractPrevious research suggests mowing practices following azoxystrobin application alter pest control and residue fate. Azoxystrobin, an acropetal penetrant quinone outside inhibitor fungicide, is commonly applied in turfgrass and other agricultural settings, protecting desired plants from fungal pathogens by inhibiting fungal growth. Field research was initiated in Raleigh, NC, and repeated in time to assess the effect of post‐application mowing timing and clipping collection practices on azoxystrobin residue persistence in tall fescue (Schedonorus arundinaceus Schreb.). At trial initiation, azoxystrobin was applied at the maximum single application rate (0.61 kg ai ha−1) to tall fescue plots. To determine the effect of initial mowing timing, plots were mowed (9.5 cm) at 0, 1, 2, 3, 7, or 14 days after application (DAA). To determine the effect of clipping removal, plots were mowed at 3, 10, and 17 DAA and clippings were either returned to the canopy or bagged and removed. Concurrently, soil cores (92 cm2) were collected at 3, 7, 14, and 21 DAA and then segmented into remaining aboveground vegetation and soil (0.0‐ to 2.5‐cm depth) for residue analyses. Mowing timing affected azoxystrobin residue in the vegetation and in soil. When clippings were returned to the canopy, 5% more azoxystrobin was detected in the vegetation at 7 and 14 DAA. At 3 and 7 DAA, in the soil, returning clippings resulted in >3% more of the applied azoxystrobin compared to removing clippings. Data from this research may allow for extended fungicide intervals for brown patch suppression and demonstrate the importance of returning clipping to turf systems to retain azoxystrobin residues.

The divergence of DHN-derived melanin pathways in Metarhizium robertsii.

The important role of dihydroxynaphthalene-(DHN) melanin in enhancing fungal stress resistance and its importance in fungal development and pathogenicity are well-established. This melanin also aids biocontrol fungi in surviving in the environment and effectively infecting insects. However, the biosynthetic origin of melanin in the biocontrol agents, Metarhizium spp., has remained elusive due to the complexity resulting from the divergence of two DHN-like biosynthetic pathways. Through the heterologous expression of biosynthetic enzymes from these two pathways in baker's yeast Saccharomyces cerevisiae, we have confirmed the presence of DHN biosynthesis in M. roberstii, and discovered a novel naphthopyrone intermediate, 8, that can produce a different type of pigment. These two pigment biosynthetic pathways differ in terms of polyketide intermediate structures and subsequent modification steps. Stress resistance studies using recombinant yeast cells have demonstrated that both DHN and its intermediates confer resistance against UV light prior to polymerization; a similar result was observed for its naphthopyrone counterpart. This study contributes to the understanding of the intricate and diverse biosynthetic mechanisms of fungal melanin and has the potential to enhance the application efficiency of biocontrol fungi such as Metarhizium spp. in agriculture.

Effect of Ozonized Water against Pathogenic Bacteria and Filamentous Fungi on Stainless Steel

Ozone is a molecule that has gained increasing interest in recent years by food industries for sanitization of food-grade surfaces. Compared to chemical sanitizers such as chlorine, hydrogen peroxide, or peracetic acid, ozone shows undeniable advantages, such as the absence of by-products that should affect human health or the possibility of generating it when needed. Therefore, the aim of this paper was the assessment of the resistance to ozonized water of two pathogenic bacteria (Listeria monocytogenes, Salmonella) and of three airborne food-spoiling fungi (Aspergillus brasiliensis, Hyphopichia burtonii, and Penicillium nordicum) inoculated on stainless steel tiles and treated in static conditions with 1 to 6 mg L−1 (pathogens) or 8.5 mg L−1 (filamentous fungi). Ozonized water gave different results based on the tested microorganisms: pathogenic bacteria proved markedly more sensible to ozone than filamentous fungi, even if great differences were observed at inter- and intra-specific levels for both categories of microorganisms. Nevertheless, the non-linear inactivation kinetics of the studied strains made the calculation of a punctual F-value difficult, so in industrial practice, adequate tailoring of the treatments to be applied, based on the registered extrinsic factors and the industrial bio-burden, would be appropriate.

Diversity and Distribution of Fungal Infections in Rwanda: High Risk and Gaps in Knowledge, Policy, and Interventions

Fungal infections (FIs) are spreading globally, raising a significant public health concern. However, its documentation remains sparse in Africa, particularly in Rwanda. This report provides a comprehensive review of FIs in Rwanda based on a systematic review of reports published between 1972 and 2022. The findings reveal a rich diversity of fungal pathogens, including Blastomyces, Candida, Cryptococcus, Histoplasma, Microsporum, Pneumocystis, Rhinosporidium, and Trichophyton caused human infections. Candida infections predominantly affect the vagina mucosa, while Histoplasma duboisi was linked to disseminated infections. Other pathogens, such as Blastomyces dermatitidis and Rhinosporidium seeberi, were associated with cerebellar and nasal mucosa infections, respectively. The widespread observation of soilborne fungi affecting bean crops highlights the pathogens’ threat to agricultural productivity, food security, and socioeconomic stability, as well as potential health impacts on humans, animals, and the environment. Of particular importance is that there is no information about FIs among animals in the country. Moreover, the analysis underscores significant limitations in the detection, reporting, and healthcare services related to FIs in the country, indicating gaps in diagnostic capacity and surveillance systems. This is underscored by the predominant use of traditional diagnostic techniques, including culture, cytology, and histopathology in the absence of integrating more sensitive and specific molecular tools in investigating FIs. Developing the diagnostic capacities and national surveillance systems are urgently needed to improve the health of crops, animals, and humans, as well as food security and socioeconomic stability in Rwanda. Also, it is important to indicate severe gaps in the evidence to inform policymaking, guide strategic planning, and improve healthcare and public health services, underscoring the urgent need to build national capacity in fungal diagnosis, surveillance, and research. Raising awareness among the public, scientific community, healthcare providers, and policymakers remains crucial. Furthermore, this report reveals the threats of FIs on public health and food insecurity in Rwanda. A multisectoral one health strategy is essential in research and intervention to determine and reduce the health and safety impacts of fungal pathogens on humans, animals, and the environment.

Study on the preservation effect of 60Co-γ ray irradiation on potatoes

To evaluate the effect of irradiation on the preservation of potatoes, fresh potatoes were selected as the irradiation objects, and irradiated with 60Co-γ radiation source for 0, 100, 200, 500 and 1000 Gy, respectively. During the irradiation, the well-packaged Y1.79Bi0.01Eu0.2MgTiO6 novel thermoluminescence dosimeter material was placed together with the potatoes at the same position. Then, the potatoes were stored in the same temperature and humidity environment, and the quality changes of the potatoes were observed. The Y1.79Bi0.01Eu0.2MgTiO6 material had good performance indicators, and was used to measure the irradiation dose of the potatoes. The experiment showed that irradiation could appropriately extend the storage time of potatoes, and gamma irradiation of about 1000 Gy could achieve the best preservation effect. The main pathogenic fungi that cause dry rot of potatoes were Fusarium solani and Fusarium oxysporum, and the appropriate dose of 60Co-γ irradiation could effectively inhibit the spread and growth of these fungi.

Whole genome regulatory effect of MoISW2 and consequences for the evolution of the rice plant pathogenic fungus Magnaporthe oryzae.

Isw2 proteins, ubiquitous across eukaryotes, exhibit a propensity for DNA binding and exert dynamic influences on local chromosome condensation in an ATP-dependent fashion, thereby modulating the accessibility of neighboring genes to transcriptional machinery. Here, we report the deletion of a putative MoISW2 gene, yielding substantial ramifications on plant pathogenicity. Subsequent gene complementation and chromatin immunoprecipitation sequencing (ChIP-seq) analyses were conducted to delineate binding sites. RNA sequencing (RNA-seq) assays revealed discernible impacts on global gene regulation along chromosomes in both mutant and wild-type strains, with comparative analyses against 55 external RNA-seq data sets corroborating these findings. Notably, MoIsw2-mediated binding and activities delineate genomic loci characterized by pronounced gene expression variability proximal to MoIsw2 binding sites, juxtaposed with comparatively stable expression in surrounding regions. The contingent genes influenced by MoIsw2 activity predominantly encompass niche-determinant genes, including those encoding secreted proteins, secondary metabolites, and stress-responsive elements, alongside avirulence genes. Furthermore, our investigations unveil a spatial correlation between MoIsw2 binding motifs and known transposable elements (TEs), suggesting a potential interplay wherein TE transposition at these loci could modulate the transcriptional landscape of Magnaporthe oryzae in a strain-specific manner. Collectively, these findings position MoIsw2 as a plausible master regulator orchestrating the delicate equilibrium between genes vital for biomass proliferation, akin to housekeeping genes, and niche-specific determinants crucial for ecological adaptability. Stress-induced TE transposition, in conjunction with MoIsw2 activity, emerges as a putative mechanism fostering enhanced mutagenesis and accelerated evolution of niche-determinant genes relative to housekeeping counterparts.IMPORTANCEIsw2 proteins are conserved in plants, fungi, animals, and other eukaryotes. We show that a fungal Isw2 protein in the rice pathogen Magnaporthe oryzae binds to retrotransposon (RT) DNA motifs and affects the epigenetic gene expression landscape of the fungal genome. Mainly ecological niche determinant genes close to the binding motifs are affected. RT elements occur frequently in DNA between genes in most organisms. They move place and multiply in the genome, especially under physiological stress. We further discuss the Isw2 and RT combined activities as a possible sought-after mechanism that can cause biased mutation rates and faster evolution of genes necessary for reacting to abiotic and biotic challenges. The most important biotic challenges for plant pathogens are the ones from the host plants' innate immunity. The overall result of these combined activities will be an adaptation-directed evolution of niche-determinant genes.

A novel ormycovirus isolated from the plant-pathogenic fungus Fusarium graminearum.

In this study, we identified a novel mycovirus, Fusarium graminearum ormycovirus 1 (FgOV1), from the pathogenic fungus Fusarium graminearum. The virus has two RNA segments, RNA1 and RNA2, with lengths of 2,591 and 1,801 nucleotides, respectively, excluding the polyA tail. Each segment contains a single open reading frame (ORF). The ORF in RNA1 encodes an RNA-dependent RNA polymerase, while the ORF in RNA2 encodes a hypothetical protein. Phylogenetic analysis showed that FgOV1 belongs to the gammaormycovirus clade, whose members are related to betaormycoviruses. To our knowledge, this is the first report of an ormycovirus in Fusarium graminearum.

Exploring the Modern Fungicides for the In vitro Management of Pokkah Boeng Disease of Maize Caused by Fusarium verticillioides (SACC.) Nirenberg

Pokkah boeng disease caused by Fusarium verticillioides is an emerging fungal disease affecting maize recently leading to substantial yield losses. The increasing resistance of pathogens to older fungicides, along with environmental concerns, underscores the need for new management strategies that incorporates next-generation fungicides. In response to this challenge, a comprehensive and systematic survey was conducted in 2022-23 across the Dharwad district of Karnataka. The survey documented disease symptoms such as chlorosis at the base of leaves, malformation and twisting of the foliage. The pathogen was isolated and confirmed as F. verticillioides through molecular diagnosis. In the present study, the pathogen was tested for in vitro efficacy of modern fungicides at three different concentrations viz., 0.1, 0.15 and 0.2 per cent using poisoned food technique. In vitro testing of new generation fungicides revealed that, Tebuconazole 25.9%EC and combinations fungicides viz., Carbendazim 12%+Mancozeb 63%WP and Trifloxystrobin 25% + Tebuconazole 50%WG resulted in 100 per cent inhibition of the mycelial growth of the pathogen. Hexaconazole 5%SC, Azoxystrobin 23%SC, Trifloxystrobin 25%SC, Tricyclazole 18%+Mancozeb 62% WP and Azoxystrobin 18.2%+Difenoconazole 11.4%SC inhibited mycelial growth by 99.15, 85.49, 85.57 93.08 and 86.87 per cent, respectively. The mycelial growth in fungicide-treated media appeared either fluffy or cottony. Among the fungicides tested, Carbendazim 12% + Mancozeb 63% WP, Trifloxystrobin 25% + Tebuconazole 50% WG, and Tebuconazole 25.9%EC demonstrated 100 per cent efficacy in inhibiting pathogen mycelial growth, even at a low concentration of 0.1%. These results suggest a promising direction for disease management, while the other fungicides tested were found to be less effective.

Antifungal activity of grape associated bacterial endophytes against pathogenic fungi

Antifungal activity of grape associated bacterial endophytes against pathogenic fungi