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World Journal of Microbiology &... Jun 2024Alternaria alternata is a prevalent postharvest pathogen that generates diverse mycotoxins, notably alternariol (AOH) and alternariol monomethyl ether (AME), which are...
Alternaria alternata is a prevalent postharvest pathogen that generates diverse mycotoxins, notably alternariol (AOH) and alternariol monomethyl ether (AME), which are recurrent severe contaminants. Nitrogen sources modulate fungal growth, development, and secondary metabolism, including mycotoxin production. The GATA transcription factor AreA regulates nitrogen source utilization. However, little is known about its involvement in the regulation of nitrogen utilization in A. alternata. To examine the regulatory mechanism of AaAreA on AOH and AME biosynthesis in A. alternata, we analyzed the impact of diverse nitrogen sources on the fungal growth, conidiation and mycotoxin production. The use of a secondary nitrogen source (NaNO) enhanced mycelial elongation and sporulation more than the use of a primary source (NHCl). NaNO favored greater mycotoxin accumulation than did NHCl. The regulatory roles of AaAreA were further clarified through gene knockout. The absence of AaAreA led to an overall reduction in growth in minimal media containing any nitrogen source except NHCl. AaAreA positively regulates mycotoxin biosynthesis when both NHCl and NaNO are used as nitrogen sources. Subcellular localization analysis revealed abundant nuclear transport when NaNO was the sole nitrogen source. The regulatory pathway of AaAreA was systematically revealed through comprehensive transcriptomic analyses. The deletion of AaAreA significantly impedes the transcription of mycotoxin biosynthetic genes, including aohR, pksI and omtI. The interaction between AaAreA and aohR, a pathway-specific transcription factor gene, demonstrated that AaAreA binds to the aohR promoter sequence (5'-GGCTATGGAAA-3'), activating its transcription. The expressed AohR regulates the expression of downstream synthase genes in the cluster, ultimately impacting mycotoxin production. This study provides valuable information to further understand how AreA regulates AOH and AME biosynthesis in A. alternata, thereby enabling the effective design of control measures for mycotoxin contamination.
Topics: Alternaria; Mycotoxins; GATA Transcription Factors; Gene Expression Regulation, Fungal; Nitrogen; Fungal Proteins; Lactones; Spores, Fungal
PubMed: 38850454
DOI: 10.1007/s11274-024-04045-4 -
Journal of Applied Microbiology Jun 2024Understanding the inhibitory effects of natural organic substances on soil-borne pathogenic fungi and the relevant molecular mechanisms are highly important for future...
AIMS
Understanding the inhibitory effects of natural organic substances on soil-borne pathogenic fungi and the relevant molecular mechanisms are highly important for future development of green prevention and control technology against soil-borne diseases. Our study elucidates the inhibitory effect of the combined application of humic acids (HAs) and chitosan on Alternariasolani and the light on the corresponding mechanism.
METHODS AND RESULTS
The effect on A. solani growth by HAs incorporated with chitosan was investigated by plate culture and the corresponding mechanism was revealed using transcriptomics. The colony growth of A. solani was suppressed with the highest inhibition rate 33.33% when swine manure HAs was compounded with chitosan at a ratio of 1:4. Chitosan changed the colony morphology from round to irregularly. RNA-seq in the HAs and chitosan (HC) treatment revealed 239 differentially expressed genes compared with the control. The unigenes associated with enzymes activities related to growth and biological processes closely related to mycelial growth and metabolism were downregulated. RNA-seq also revealed that chitosan altered the expression of genes related to secondary metabolism, fungal cell wall formation and polysaccharide synthesis, and metabolism. Meanwhile, weighted gene co-expression network analysis showed that, genes expression in the module positively correlated with mycelial growth was significantly reduced in the HC treatment; and the results were verified by real-time quantitative polymerase chain reaction.
CONCLUSIONS
The co-inhibition effect of HAs and chitosan on A. solani is associated with downregulated genes expression correlated with mycelial growth.
Topics: Chitosan; Humic Substances; Gene Expression Profiling; Alternaria; Animals; Transcriptome; Swine; Manure; Soil Microbiology; Mycelium
PubMed: 38849313
DOI: 10.1093/jambio/lxae131 -
Plant Molecular Biology Jun 2024Alternaria leaf blight (ALB), caused by a necrotrophic fungus Alternaria brassicae is a serious disease of oleiferous Brassicas resulting in significant yield losses...
Alternaria leaf blight (ALB), caused by a necrotrophic fungus Alternaria brassicae is a serious disease of oleiferous Brassicas resulting in significant yield losses worldwide. No robust resistance against A. brassicae has been identified in the Brassicas. Natural accessions of Arabidopsis show a spectrum of responses to A. brassicae ranging from high susceptibility to complete resistance. To understand the molecular mechanisms of resistance/ susceptibility, we analysed the comparative changes in the transcriptome profile of Arabidopsis accessions with contrasting responses- at different time points post-infection. Differential gene expression, GO enrichment, pathway enrichment, and weighted gene co-expression network analysis (WGCNA) revealed reprogramming of phenylpropanoid biosynthetic pathway involving lignin, hydroxycinnamic acids, scopoletin, anthocyanin genes to be highly associated with resistance against A. brassicae. T-DNA insertion mutants deficient in the biosynthesis of coumarin scopoletin exhibited enhanced susceptibility to A. brassicae. The supplementation of scopoletin to medium or exogenous application resulted in a significant reduction in the A. brassicae growth. Our study provides new insights into the transcriptome dynamics in A. brassicae-challenged Arabidopsis and demonstrates the involvement of coumarins in plant immunity against the Brassica pathogen A. brassicae.
Topics: Arabidopsis; Alternaria; Plant Diseases; Disease Resistance; Transcriptome; Gene Expression Regulation, Plant; Scopoletin; Gene Expression Profiling; Arabidopsis Proteins
PubMed: 38842571
DOI: 10.1007/s11103-024-01453-w -
Scientific Reports Jun 2024Alternaria alternata fungus is a potent paclitaxel producer isolated from Corylus avellana. The major challenge is the lack of optimized media for endophytic fungi...
Alternaria alternata fungus is a potent paclitaxel producer isolated from Corylus avellana. The major challenge is the lack of optimized media for endophytic fungi productivity. In the effort to maximize the production of taxoids by A. alternata, several fermentation conditions, including pH (pH 4.0-7.0), different types and concentrations of carbon (fructose, glucose, sucrose, mannitol, sorbitol, and malt extract), and nitrogen (urea, ammonium nitrate, potassium nitrate, ammonium phosphate, and ammonium sulfate) were applied step by step. Based on the results, A. alternata in a medium containing sucrose 5% (w/v) and ammonium phosphate 2.5 mM at pH 6.0 showed a rapid and sustainable growth rate, the highest paclitaxel yield (94.8 µg gFW vs 2.8 µg gFW in controls), and the maximum content of amino acids. Additionally, the effect of pectin was evaluated on fungus, and mycelia harvested. Pectin significantly enhanced the growth and taxoid yield on day 21 (respectively 171% and 116% of their corresponding on day 7). The results were checked out by mathematical modeling as well. Accordingly, these findings suggest a low-cost, eco-friendly, and easy-to-produce approach with excellent biotechnological potential for the industrial manufacture of taxoids.
Topics: Alternaria; Fermentation; Pectins; Culture Media; Paclitaxel; Models, Theoretical; Hydrogen-Ion Concentration; Nitrogen
PubMed: 38839906
DOI: 10.1038/s41598-024-63681-w -
Archiv Der Pharmazie Jun 2024It is generally believed that the main influencing factors of plant metabolism are genetic and environmental factors. However, the transformation and catalysis of... (Review)
Review
It is generally believed that the main influencing factors of plant metabolism are genetic and environmental factors. However, the transformation and catalysis of metabolic intermediates by endophytic fungi have become a new factor and resource attracting attention in recent years. There are over 2000 precious plant species in the Astragalus genus. In the past decade, at least 303 high-value metabolites have been isolated from the Astragalus medicinal plants, including 124 saponins, 150 flavonoids, two alkaloids, six sterols, and over 20 other types of compounds. These medicinal plants contain abundant endophytic fungi with unique functions, and nearly 600 endophytic fungi with known identity have been detected, but only about 35 strains belonging to 13 genera have been isolated. Among them, at least four strains affiliated to Penicillium roseopurpureum, Alternaria eureka, Neosartorya hiratsukae, and Camarosporium laburnicola have demonstrated the ability to biotransform four saponin compounds from the Astragalus genus, resulting in the production of 66 new compounds, which have significantly enhanced our understanding of the formation of metabolites in plants of the Astragalus genus. They provide a scientific basis for improving the cultivation quality of Astragalus plants through the modification of dominant fungal endophytes or reshaping the endophytic fungal community. Additionally, they open up new avenues for the discovery of specialized, green, efficient, and sustainable biotransformation pathways for complex pharmaceutical intermediates.
PubMed: 38838334
DOI: 10.1002/ardp.202400249 -
Phytopathology Jun 2024Rapid detection of plant diseases before they escalate can improve disease control. Our team has developed rapid nucleic acid extraction methods with microneedles (MN)...
Rapid detection of plant diseases before they escalate can improve disease control. Our team has developed rapid nucleic acid extraction methods with microneedles (MN) and combined these with LAMP assays for pathogen detection in the field. In this work, we developed LAMP assays for early blight (, , and ) and bacterial spot of tomato () and validated these LAMP assays and two previously developed LAMP assays for tomato spotted wilt virus and late blight. Tomato plants were inoculated and disease severity was measured. Extractions were performed using MN and LAMP assays were run in tubes (with hydroxynaphthol blue) on a heat block or on a newly designed microfluidic slide chip on a heat block or a slide heater. Fluorescence on the microfluidic chip slides was visualized using EvaGreen and photographed on a smartphone. Plants inoculated with or tomato spotted wilt virus tested positive prior to visible disease symptoms, while and were detected at the time of visual disease symptoms. LAMP assays were more sensitive than PCR and the limit of detection was 1 pg of DNA for both and . The LAMP assay designed for early blight detected all three species of that infect tomato and is thus an spp. assay. This study demonstrates the utility of rapid MN extraction followed by LAMP on a microfluidic chip for rapid diagnosis of four important tomato pathogens.
PubMed: 38829831
DOI: 10.1094/PHYTO-12-23-0481-R -
Allergy May 2024We investigated the biological function of the mould allergen Alt a 1 as a carrier of micronutrients, such as the vitamin A metabolite retinoic acid (RA) and the...
BACKGROUND
We investigated the biological function of the mould allergen Alt a 1 as a carrier of micronutrients, such as the vitamin A metabolite retinoic acid (RA) and the influence of RA binding on its allergenicity in vitro and in vivo.
METHODS
Alt a 1-RA complex formation was analyzed in silico and in vitro. PBMCs from Alternaria-allergic donors were stimulated with Alt a 1 complexed with RA (holo-Alt a 1) or empty apo-Alt a 1 and analyzed for cytokine production and CD marker expression. Serum IgE-binding and crosslinking assays to apo- and holo-protein were correlated to B-cell epitope analysis. Female BALB/c mice already sensitized to Alt a 1 were intranasally treated with apo-Alt a 1, holo-Alt a 1 or RA alone before measuring anaphylactic response, serum antibody levels, splenic cytokines and CD marker expression.
RESULTS
In silico docking calculations and in vitro assays showed that the extent of RA binding depended on the higher quaternary state of Alt a 1. Holo-Alt a 1 loaded with RA reduced IL-13 released from PBMCs and CD3+CD4+CRTh2 cells. Complexing Alt a 1 to RA masked its IgE B-cell epitopes and reduced its IgE-binding capacity. In a therapeutic mouse model of Alternaria allergy nasal application of holo-Alt a 1, but not of apo-Alt a 1, significantly impeded the anaphylactic response, impaired splenic antigen-presenting cells and induced IL-10 production.
CONCLUSION
Holo-Alt a 1 binding to RA was able to alleviate Th2 immunity in vitro, modulate an ongoing Th2 response and prevent anaphylactic symptoms in vivo, presenting a novel option for improving allergen-specific immunotherapy in Alternaria allergy.
PubMed: 38818808
DOI: 10.1111/all.16181 -
International Journal of Food... Aug 2024During postharvest, table grapes are often spoiled by molds. Aspergillus sp., Alternaria sp., Botrytis sp., Cladosporium sp. and Penicillium sp. are different mold... (Review)
Review
During postharvest, table grapes are often spoiled by molds. Aspergillus sp., Alternaria sp., Botrytis sp., Cladosporium sp. and Penicillium sp. are different mold genera frequently related to table grape rot. Fungal spoilage affects nutritional value and organoleptic properties while also producing health hazards, such as mycotoxins. Traditionally, synthetic fungicides have been employed to control fungal diseases. However, possible negative effects on health and the environment are a serious concern for consumers and government entities. This review summarized data on innovative strategies proposed to diminish postharvest losses and extend table grape shelf life. Among physical, chemical, and biological strategies, either alone or in combination, the integrated management of fungal diseases is a sustainable alternative to synthetic fungicides. However, to date, only a few alternative technologies have succeeded on a commercial scale. Recent research aimed at increasing the competitiveness of alternative technologies has led to the development of integrated management strategies to prevent postharvest decay and increase the safety and quality of table grapes.
Topics: Vitis; Fungi; Food Preservation; Food Microbiology; Food Contamination
PubMed: 38815343
DOI: 10.1016/j.ijfoodmicro.2024.110766 -
Heliyon May 2024Asia has a rich history of cultivating sweet cherries, a practice that has been carried out since ancient times. However, the effective management of Alternaria disease...
Asia has a rich history of cultivating sweet cherries, a practice that has been carried out since ancient times. However, the effective management of Alternaria disease in sweet cherry crops has presented a formidable challenge, resulting in notable decreases in yield. Various attempts have been made to employ both chemical and biological treatments; however, their effectiveness has been restricted. In order to tackle this problem, an investigation was carried out, with the primary objective of isolating and identifying isolates that are accountable for the occurrence of sweet cherry soft spot rot. Out of the twelve isolates examined, the CHM-4 isolate was found to be the most pathogenic. Its identification was achieved through the use of the ITS genomic region (ITS1 and ITS4), and the BLAST results revealed a 95 % similarity with (MG744381.1). The objective of the research was to explore the potential of silver nanoparticles (SNPs) synthesized by phytosynthesis as a novel antifungal agent to combat sweet cherry soft spot pathogenicity. The biosynthesis of SNPs was carried out using sweet cherry fruits kernel exudate, which served as an environmentally friendly source. The exudates exhibited the ability to produce nanoparticles with an average size of 24.97 nm. Analysis conducted using a transmission electron microscope (TEM) revealed the multifaceted structure of these nanoparticles. Furthermore, when tested at concentrations of 5, 10, 20, and 40 μg/ml, these biosynthetic nanoparticles demonstrated the capability to inhibit the growth of Alternaria fungi and effectively destroy fungal hyphae. It is advisable to utilize diverse components of sweet cherry for the synthesis of various nanoparticles owing to their compatibility with the surrounding environment.
PubMed: 38813185
DOI: 10.1016/j.heliyon.2024.e31508 -
The Science of the Total Environment Aug 2024Since plastic waste has become a worldwide pollution problem, studying the ability of marine microorganisms to degrade plastic waste is important. However, conventional...
Since plastic waste has become a worldwide pollution problem, studying the ability of marine microorganisms to degrade plastic waste is important. However, conventional methods are unable to in situ real-time study the ability of microorganisms to biodegrade plastics. In recent years, Raman spectroscopy has been widely used in the characterization of plastics as well as in the study of biological metabolism due to its low cost, rapidity, label-free, non-destructive, and water-independent features, which provides us with new ideas to address the above limitations. Here, we have established a method to study the degradation ability of microorganisms on plastics using confocal Raman imaging. Alternaria alternata FB1, a recently reported polyethylene (PE) degrading marine fungus, is used as a model to perform a long-term (up to 274 days) in situ real-time nondestructive inspection of its degradation process. We can prove the degradation of PE plastics from the following two aspects, visualization and analysis of the degradation process based on depth imaging and quantification of the degradation rate by crystallinity calculations. The findings also reveal unprecedented degradation details. The method is important for realizing high-throughput screening of microorganisms with potential to degrade plastics and studying the degradation process of plastics in the future.
Topics: Biodegradation, Environmental; Polyethylene; Spectrum Analysis, Raman; Alternaria; Water Pollutants, Chemical
PubMed: 38810744
DOI: 10.1016/j.scitotenv.2024.173582