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Microbiology (Reading, England) Mar 2022is a common species of fungus frequently isolated from plants as both an endophyte and a pathogen. Although the current definition of rests on a foundation of... (Review)
Review
is a common species of fungus frequently isolated from plants as both an endophyte and a pathogen. Although the current definition of rests on a foundation of morphological, genetic and genomic analyses, doubts persist regarding the scope of within the genus due to the varied symbiotic interactions and wide host range observed in these fungi. These doubts may be due in large part to the history of unstable taxonomy in , based on limited morphological characters for species delimitation and host specificity associated with toxins encoded by genes carried on conditionally dispensable chromosomes. This review explores the history of taxonomy, focusing in particular on the use of nutritional mode and host associations in species delimitation, with the goal of evaluating as it currently stands based on taxonomic best practice. Given the recombination detected among isolates of , different symbiotic associations in this species should not be considered phylogenetically informative.
Topics: Alternaria; Endophytes; Host Specificity; Plant Diseases
PubMed: 35348451
DOI: 10.1099/mic.0.001153 -
Methods in Molecular Biology (Clifton,... 2017The genus Alternaria includes more than 250 species. The traditional methods for identification of Alternaria species are based on morphological characteristics of the... (Review)
Review
The genus Alternaria includes more than 250 species. The traditional methods for identification of Alternaria species are based on morphological characteristics of the reproductive structures and sporulation patterns under controlled culture conditions. Cladistics analyses of "housekeeping genes" commonly used for other genera, failed to discriminate among the small-spored Alternaria species. The development of molecular methods achieving a better agreement with morphological differences is still needed. The production of secondary metabolites has also been used as a means of classification and identification. Alternaria spp. can produce a wide variety of toxic metabolites. These metabolites belong principally to three different structural groups: (1) the dibenzopyrone derivatives, alternariol (AOH), alternariol monomethyl ether (AME), and altenuene (ALT); (2) the perylene derivative altertoxins (ATX-I, ATX-II, and ATX II); and (3) the tetramic acid derivative, tenuazonic acid (TeA). TeA, AOH, AME, ALT, and ATX-I are the main. Certain species in the genus Alternaria produce host-specific toxins (HSTs) that contribute to their pathogenicity and virulence. Alternaria species are plant pathogens that cause spoilage of agricultural commodities with consequent mycotoxin accumulation and economic losses. Vegetable foods infected by Alternaria rot could introduce high amounts of these toxins to the human diet. More investigations on the toxic potential of these toxins and their hazard for human consumption are needed to make a reliable risk assessment of dietary exposure.
Topics: Alternaria; Animal Feed; Animals; Food Contamination; Food Safety; Host-Pathogen Interactions; Humans; Metabolome; Metabolomics; Mycotoxins; Plants; Secondary Metabolism
PubMed: 27924529
DOI: 10.1007/978-1-4939-6707-0_2 -
Molecules (Basel, Switzerland) May 2013Alternaria is a cosmopolitan fungal genus widely distributing in soil and organic matter. It includes saprophytic, endophytic and pathogenic species. At least 268... (Review)
Review
Alternaria is a cosmopolitan fungal genus widely distributing in soil and organic matter. It includes saprophytic, endophytic and pathogenic species. At least 268 metabolites from Alternaria fungi have been reported in the past few decades. They mainly include nitrogen-containing metabolites, steroids, terpenoids, pyranones, quinones, and phenolics. This review aims to briefly summarize the structurally different metabolites produced by Alternaria fungi, as well as their occurrences, biological activities and functions. Some considerations related to synthesis, biosynthesis, production and applications of the metabolites from Alternaria fungi are also discussed.
Topics: Alternaria; Mycotoxins; Plant Diseases
PubMed: 23698046
DOI: 10.3390/molecules18055891 -
Mycologia 2021The genus contains a diversity of saprobic and pathogenic species that can be found in a wide range of environments. is currently divided into 26 subgeneric sections,... (Review)
Review
The genus contains a diversity of saprobic and pathogenic species that can be found in a wide range of environments. is currently divided into 26 subgeneric sections, and the "small-spored" section includes many species that are economically important agricultural pathogens. Recognizing that a stable framework for systematics and species identification is essential for management and regulation purposes, this section has experienced much taxonomic debate and systematic revision in recent years. Molecular phylogenetic studies have challenged the reliability of using morphological characteristics to differentiate species but have also suggested that commonly used molecular markers for fungal phylogenetics may not be sufficiently informative at this taxonomic level. To allow the assessment of molecular variation and evolutionary history at a genome-wide scale, we present an overview and analysis of phylogenomic resources for section . We review the currently available genomic resources and report five newly sequenced genomes. We then perform multiple comparative genomic analyses, including macrosynteny assessment and inference of phylogenetic relationships using a variety of data sets and analysis methods. Fine-scale, genome-wide phylogenetic reconstruction revealed incomplete lineage sorting and the genomic distribution of gene/species tree discordance. Based on these patterns, we propose a list of candidate genes that may be developed into informative markers that are diagnostic for the main lineages. This overview identifies gaps in knowledge and can guide future genome sequencing efforts for this important group of plant pathogenic fungi.
Topics: Alternaria; Genome-Wide Association Study; Phylogeny; Reproducibility of Results
PubMed: 34637684
DOI: 10.1080/00275514.2021.1950456 -
Clinical Microbiology and Infection :... Aug 2008The genus Alternaria contains several species of melanized hyphomycetes that cause opportunistic human infections. The published literature contains 210 reported cases... (Review)
Review
The genus Alternaria contains several species of melanized hyphomycetes that cause opportunistic human infections. The published literature contains 210 reported cases of human alternarioses between 1933 and the present day. The most frequent clinical manifestations are cutaneous and subcutaneous infections (74.3%), followed by oculomycosis (9.5%), invasive and non-invasive rhinosinusitis (8.1%) and onychomycosis (8.1%). Immunosuppression is frequently associated with cutaneous and subcutaneous infections and rhinosinusitis. The most important risk factors for cutaneous and subcutaneous infections are solid organ transplantation and Cushing's syndrome, and those for rhinosinusitis are bone marrow transplants. Having been exposed to soil and garbage is common in all cases of oculomycosis, with corticotherapy being a risk factor in 50% of these cases. Previous contact with soil and/or trauma to the nails is associated with most cases of onychomycosis. In general, alternariosis shows a good response to conventional antifungal drugs. On some occasions, steroid suppression or reduction is sufficient to resolve an infection. Itraconazole is the antifungal drug used most frequently to successfully treat onychomycosis and cutaneous and subcutaneous infections. Posaconazole and voriconazole are promising therapeutic options, with the latter being especially so for oculomycosis.
Topics: Alternaria; Antifungal Agents; Clinical Laboratory Techniques; Dermatomycoses; Eye Infections, Fungal; Humans; Mycoses
PubMed: 18727797
DOI: 10.1111/j.1469-0691.2008.02024.x -
Scientific Reports Feb 2020Iron is one of the most abundant elements on earth and essential for life. However, Fe ions are rather insoluble and microorganisms such as fungi may use siderophores as...
Iron is one of the most abundant elements on earth and essential for life. However, Fe ions are rather insoluble and microorganisms such as fungi may use siderophores as strong chelators for uptake. In addition, free cytoplasmic iron is rather toxic and intracellular siderophores are used to control the toxicity. Siderophores are also important for iron storage. We studied two siderophore systems in the plant necrotrophic fungus Alternaria alternata and show that the non-ribosomal peptide synthase, Nps2, is required for the biosynthesis of intracellular ferricrocin, whereas Nps6 is needed for the formation of extracellular coprogen and coprogen B. Whereas nps2 was dispensable for growth on iron-depleted medium, nps6 was essential under those conditions. nps2 deletion caused an increase in spore formation and reduced pathogenicity on tomato. Our results suggest that A. alternata employs an external and an internal siderophore system to adapt to low iron conditions.
Topics: Alternaria; Fungal Proteins; Gene Expression Regulation, Fungal; Iron; Peptide Synthases; Siderophores
PubMed: 32107432
DOI: 10.1038/s41598-020-60468-7 -
Revista Chilena de Infectologia :... Oct 2014
Topics: Alternaria
PubMed: 25491460
DOI: 10.4067/S0716-10182014000500013 -
Environmental Microbiology Oct 2023The wild relatives of modern tomato crops are native to South America. These plants occur in habitats as different as the Andes and the Atacama Desert and are, to some...
The wild relatives of modern tomato crops are native to South America. These plants occur in habitats as different as the Andes and the Atacama Desert and are, to some degree, all susceptible to fungal pathogens of the genus Alternaria. Alternaria is a large genus. On tomatoes, several species cause early blight, leaf spots and other diseases. We collected Alternaria-like infection lesions from the leaves of eight wild tomato species from Chile and Peru. Using molecular barcoding markers, we characterized the pathogens. The infection lesions were caused predominantly by small-spored species of Alternaria of the section Alternaria, like A. alternata, but also by Stemphylium spp., Alternaria spp. from the section Ulocladioides and other related species. Morphological observations and an infection assay confirmed this. Comparative genetic diversity analyses show a larger diversity in this wild system than in studies of cultivated Solanum species. As A. alternata has been reported to be an increasing problem in cultivated tomatoes, investigating the evolutionary potential of this pathogen is not only interesting to scientists studying wild plant pathosystems. It could also inform crop protection and breeding programs to be aware of potential epidemics caused by species still confined to South America.
Topics: Solanum lycopersicum; Alternaria; Solanum; Crops, Agricultural; Chile
PubMed: 37171093
DOI: 10.1111/1462-2920.16394 -
Doklady Biological Sciences :... Dec 2022Fungi of the genus Alternaria are producers of biologically active compounds. Alternaria japonica is pathogenic to small radish and certain other crucifers, but has not...
Fungi of the genus Alternaria are producers of biologically active compounds. Alternaria japonica is pathogenic to small radish and certain other crucifers, but has not been studied in sufficient detail. Discrepant data on its toxic metabolites are available in the literature, possibly because a limited set of nutritive substrates was used in culturing or species identification of the strains was incorrect. The objectives of this study were to accurately identify the Russian A. japonica strains and to assess the A. japonica toxigenic potential. Four Russian A. japonica strains were identified using a multifaceted approach, which included analyses of morphological characters (the diameter and morphology of colonies grown on the diagnostic media potato carrot agar (PCA) and yeast extract-glucose (YES) agar for one week), the conidial size, and the presence of chlamydospores), the nucleotide sequences of DNA markers (ITS and EF1α regions), and chemotaxonomic data (mycotoxin production). Biomass and extractive substance yields of A. japonica cultures were found to significantly depend on the composition of the liquid medium. Minor differences between the A. japonica strains were detected via metabolite profiling by HPLC/MS-UV. Extracts of A. japonica cultures exerted phytotoxic activity toward small radish leaves and cytotoxicity toward Paramecium caudatum to a level comparable with that of A. tenuissima extracts. Brassicicolin A, dihydrobrassicicolin A, and phomenins A and B, which are known for several species of the genus Alternaria, were identified in A. japonica extracts. Mycotoxins (alternariol, its methyl ether, tentoxin, tenuazonic acid, and altenuene), which are characteristic of the cosmopolitan species A. tenuissima, were not detected in cultures of the A. japonica strains. Extract toxicity and the yield of extractive substances were studied in the A. japonica strains, and strain MFP244011 proved promising as a producer of known and, presumably, new toxins upon culture on the M1D synthetic medium or semisynthetic liquid media (e.g., the Sabouraud medium).
Topics: Alternaria; Agar; Mycotoxins; Tenuazonic Acid
PubMed: 36781536
DOI: 10.1134/S0012496622060175 -
Mycopathologia 2003A specimen of emollient cream, which was observed to be contaminated peripherally with a filamentous fungus was examined for the presence of fungi and the resulting... (Review)
Review
A specimen of emollient cream, which was observed to be contaminated peripherally with a filamentous fungus was examined for the presence of fungi and the resulting fungal colonies were examined phenotypically and genotypically. Subsequent DNA extraction and PCR amplification of the large internal transcribed spacer region [ITS1-5.8S-ITS2] yielded an amplicon of 512 bp. Sequence analysis identified this as Alternaria alternata at the 100% homology level with all 512/512 bases called. This organism has been previously reported as a cause of opportunistic infections involving skin and immunocompromised patients. This is the first report of an emollient cream as a source of this organism. It highlights the need for proper management of such preparations in order to minimize the potential spread of fungi to susceptible patient populations.
Topics: Alternaria; Base Sequence; DNA, Fungal; DNA, Intergenic; Dermatomycoses; Emollients; Humans; Molecular Sequence Data; Polymerase Chain Reaction; Sequence Analysis, DNA
PubMed: 14682451
DOI: 10.1023/b:myco.0000003557.11875.31