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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 -
Scientific Reports May 2023The fungal genus Alternaria is a pan-global pathogen of > 100 crops, and is associated with the globally expanding Alternaria leaf blotch in apple (Malus x domestica...
The fungal genus Alternaria is a pan-global pathogen of > 100 crops, and is associated with the globally expanding Alternaria leaf blotch in apple (Malus x domestica Borkh.) which leads to severe leaf necrosis, premature defoliation, and large economic losses. Up to date, the epidemiology of many Alternaria species is still not resolved as they can be saprophytic, parasitic or shift between both lifestyles and are also classified as primary pathogen able to infect healthy tissue. We argue that Alternaria spp. does not act as primary pathogen, but only as a necrosis-dependent opportunist. We studied the infection biology of Alternaria spp. under controlled conditions and monitored disease prevalence in real orchards and validated our ideas by applying fungicide-free treatments in 3-years field experiments. Alternaria spp. isolates were not able to induce necroses in healthy tissue, but only when prior induced damages existed. Next, leaf-applied fertilizers, without fungicidal effect, reduced Alternaria-associated symptoms (- 72.7%, SE: ± 2.5%) with the same efficacy as fungicides. Finally, low leaf magnesium, sulphur, and manganese concentrations were consistently linked with Alternaria-associated leaf blotch. Fruit spot incidence correlated positively with leaf blotch, was also reduced by fertilizer treatments, and did not expand during storage unlike other fungus-mediated diseases. Our findings suggest that Alternaria spp. may be a consequence of leaf blotch rather than its primary cause, as it appears to colonize the physiologically induced leaf blotch. Taking into account existing observations that Alternaria infection is connected to weakened hosts, the distinction may appear slight, but is of great significance, as we can now (a) explain the mechanism of how different stresses result in colonization with Alternaria spp. and (b) substitute fungicides for a basic leaf fertilizer. Therefore, our findings can result in significant decreases in environmental costs due to reduced fungicide use, especially if the same mechanism applies to other crops.
Topics: Malus; Fruit; Alternaria; Fertilizers; Crops, Agricultural; Fungicides, Industrial; Necrosis; Plant Leaves
PubMed: 37225789
DOI: 10.1038/s41598-023-35448-2 -
Molecular Plant Pathology Mar 2024Alternaria spp. cause different diseases in potato and tomato crops. Early blight caused by Alternaria solani and brown spot caused by Alternaria alternata are most... (Review)
Review
UNLABELLED
Alternaria spp. cause different diseases in potato and tomato crops. Early blight caused by Alternaria solani and brown spot caused by Alternaria alternata are most common, but the disease complex is far more diverse. We first provide an overview of the Alternaria species infecting the two host plants to alleviate some of the confusion that arises from the taxonomic rearrangements in this fungal genus. Highlighting the diversity of Alternaria fungi on both solanaceous hosts, we review studies investigating the genetic diversity and genomes, before we present recent advances from studies elucidating host-pathogen interactions and fungicide resistances.
TAXONOMY
Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Pleosporales, Family Pleosporaceae, Genus Alternaria.
BIOLOGY AND HOST RANGE
Alternaria spp. adopt diverse lifestyles. We specifically review Alternaria spp. that cause disease in the two solanaceous crops potato (Solanum tuberosum) and tomato (Solanum lycopersicum). They are necrotrophic pathogens with no known sexual stage, despite some signatures of recombination.
DISEASE SYMPTOMS
Symptoms of the early blight/brown spot disease complex include foliar lesions that first present as brown spots, depending on the species with characteristic concentric rings, which eventually lead to severe defoliation and considerable yield loss.
CONTROL
Good field hygiene can keep the disease pressure low. Some potato and tomato cultivars show differences in susceptibility, but there are no fully resistant varieties known. Therefore, the main control mechanism is treatment with fungicides.
Topics: Alternaria; Solanum tuberosum; Solanum lycopersicum; Plant Diseases; Fungicides, Industrial
PubMed: 38476108
DOI: 10.1111/mpp.13435 -
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 -
Arhiv Za Higijenu Rada I Toksikologiju Dec 2011Humid indoor environments may be colonised by allergenic filamentous microfungi (moulds), Aspergillus spp., Penicillium spp., Cladosporium spp., and Alternaria spp. in... (Review)
Review
Humid indoor environments may be colonised by allergenic filamentous microfungi (moulds), Aspergillus spp., Penicillium spp., Cladosporium spp., and Alternaria spp. in particular. Mould-induced respiratory diseases are a worldwide problem. In the last two decades, mould allergens and glucans have been used as markers of indoor exposure to moulds. Recently, mould allergens Alt a 1 (Alternaria alternata) and Asp f 1 (Aspergillus fumigatus) have been analysed in various environments (residential and occupational) with enzyme-linked immunosorbent assays, which use monoclonal or polyclonal antibodies. Household Alt a 1 and Asp f 1 levels were usually under the limit of the method detection. By contrast, higher levels of mould allergens were found in environments with high levels of bioaerosols such as poultry farms and sawmills. Data on allergen Alt a 1 and Asp f 1 levels in agricultural settings may provide information on possible colonisation of respective moulds and point out to mould-related diseases in occupants.
Topics: Air Pollution, Indoor; Allergens; Alternaria; Aspergillosis; Aspergillus fumigatus; Humans; Respiratory Hypersensitivity
PubMed: 22202471
DOI: 10.2478/10004-1254-62-2011-2126 -
Toxins Nov 2022The mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), and tentoxin (TEN) are mycotoxins, which can contaminate cereal-based raw materials....
The mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), and tentoxin (TEN) are mycotoxins, which can contaminate cereal-based raw materials. Today, wheat is one of the most important crops in temperate zones, and it is in increasing demand in the Western Balkans countries that are urbanizing and industrializing. This research aimed to investigate the occurrence and determine the concentration of mycotoxins AOH, AME, and TEN in wheat samples from the Republic of Serbia and the Republic of Albania, harvested in the year 2020 in the period between 15 June and 15 July. A total of 80 wheat grain samples, 40 from each country, were analyzed by an QuEChERS (quick, easy, cheap, effective, rugged, and safe) method. From the obtained results, it can be seen that the mean concentration of AOH was 3.3 µg/kg and AME was 2.2 µg/kg in wheat samples from Serbia, while TEN from both Serbia and Albania was under the limit of quantification (
Topics: Alternaria; Mycotoxins; Triticum
PubMed: 36422965
DOI: 10.3390/toxins14110791 -
Toxins Sep 2021fungi dominate the grain microbiota in many regions of the world; therefore, the detection of species that are able to produce mycotoxins has received much attention. A...
fungi dominate the grain microbiota in many regions of the world; therefore, the detection of species that are able to produce mycotoxins has received much attention. A total of 178 grain samples of wheat, barley and oat obtained from the Urals and West Siberia regions of Russia in 2017-2019 were included in the study. Grain contamination with fungi belonging to sections and was analysed using qPCR with specific primers. The occurrence of four mycotoxins produced by , AOH, AME, TEN, and TeA, was defined by HPLC-MS/MS. DNA was found in all analysed grain samples. The prevalence of DNA of sect. fungi (range 53 × 10-21,731 × 10 pg/ng) over the DNA of sect. (range 11 × 10‒4237 × 10 pg/ng) in the grain samples was revealed. Sixty-two percent of grain samples were contaminated by at least two mycotoxins. The combination of TEN and TeA was found most often. Eight percent of grain samples were contaminated by all four mycotoxins, and only 3% of samples were free from the analysed secondary toxic metabolites. The amounts varied in a range of 2-53 µg/kg for AOH, 3-56 µg/kg for AME, 3-131 µg/kg for TEN and 9-15,000 µg/kg for TeA. To our knowledge, a new global maximum level of natural contamination of wheat grain with TeA was detected. A positive correlation between the amount of DNA from sect. and TeA was observed. The significant effects of cereal species and geographic origin of samples on the amounts of DNA and mycotoxins of spp. in grain were revealed. Barley was the most heavily contaminated with fungi belonging to both sections. The content of AOH in oat grain was, on average, higher than that found in wheat and barley. The content of TEN in the grain of barley was lower than that in wheat and similar to that in oat. The content of TeA did not depend on the cereal crop. The effect of weather conditions (summer temperature and rainfall) on the final fungal and mycotoxin contamination of grain was discussed. The frequent co-occurrence of different fungi and their mycotoxins in grain indicates the need for further studies investigating this issue.
Topics: Alternaria; Avena; DNA, Fungal; Edible Grain; Food Contamination; Hordeum; Mycotoxins; Russia; Triticum; Weather
PubMed: 34678974
DOI: 10.3390/toxins13100681 -
Mycotoxin Research May 2022A liquid chromatography tandem mass spectrometry (LC-MS/MS) multi-mycotoxin method was developed for the analysis of the Alternaria toxins alternariol (AOH), alternariol...
A liquid chromatography tandem mass spectrometry (LC-MS/MS) multi-mycotoxin method was developed for the analysis of the Alternaria toxins alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TEN), altertoxin I (ATX I), altertoxin II (ATX II), alterperylenol (ALTP), and altenuene (ALT), as well as the modified toxins AOH-3-glucoside (AOH-3-G), AOH-9-glucoside (AOH-9-G), AME-3-glucoside (AME-3-G), AOH-3-sulfate (AOH-3-S), and AME-3-sulfate (AME-3-S) in barley and malt. The toxin tenuazonic acid (TeA) was analyzed separately as it could not be included into the multi-mycotoxin method. Quantitation was conducted by using a combination of stable isotope dilution analysis (SIDA) for AOH, AME, and TeA, and matrix-matched calibration for all other toxins. Limits of detection were between 0.05 µg/kg (AME) and 2.45 µg/kg (ALT), whereas limits of quantitation ranged from 0.16 µg/kg (AME) to 8.75 µg/kg (ALT). Recoveries between 96 and 107% were obtained for the analytes when SIDA was applied, while recoveries between 84 and 112% were found for analytes quantified by matrix-matched calibration. The method was applied for the analysis of 50 barley samples and their respective malts from the harvest years 2016-2020 for their mycotoxin content, showing the overall potential of toxin formation during the malting process. The toxins ALTP and ATX I were mainly found in the malt samples, but not in barley.
Topics: Alternaria; Chromatography, High Pressure Liquid; Chromatography, Liquid; Glucosides; Hordeum; Lactones; Mycotoxins; Sulfates; Tandem Mass Spectrometry; Tenuazonic Acid
PubMed: 35396694
DOI: 10.1007/s12550-022-00455-1 -
PeerJ 2022Pathogen accumulation after introduction is unavoidable for exotic plants over a long period of time. Therefore, it is important to understand whether plant invasion...
Pathogen accumulation after introduction is unavoidable for exotic plants over a long period of time. Therefore, it is important to understand whether plant invasion promotes novel pathogen emergence and increases the risk of pathogen movement among agricultural, horticultural, and wild native plants. In this study, we used multiple gene analysis to characterize the species composition of 104 isolates of obtained from the invasive plant and native plants from Yunnan, Hubei, Guizhou, Sichuan, and Guangxi in China. Phylogenetically, these strains were from (88.5%), (10.6%) and (0.9%). There was a high amount of sharing between strains associated with and with local plants. Pathogenicity tests indicated that most of these strains are generalists; the isolates with a wider host range were more virulent to the plant. Woody plants were more resistant to these strains than herbaceous plants and vines. However, the invasive plant was highly sensitive to these strains. Our data are valuable for understanding how invasion impacts the species composition of the native plant and whether invasion causes potential disease risks in invaded ecosystems.
Topics: Ageratina; Alternaria; Ecosystem; Introduced Species; Virulence; China; Plants
PubMed: 35251785
DOI: 10.7717/peerj.13012 -
Toxins Nov 2019Mycotoxins are low-molecular weight compounds produced by diverse genera of molds that may contaminate food and feed threatening the health of humans and animals. Recent... (Review)
Review
Mycotoxins are low-molecular weight compounds produced by diverse genera of molds that may contaminate food and feed threatening the health of humans and animals. Recent findings underline the importance of studying the combined occurrence of multiple mycotoxins and the relevance of assessing the toxicity their simultaneous exposure may cause in living organisms. In this context, for the first time, this work has critically reviewed the most relevant data concerning the occurrence and toxicity of mycotoxins produced by spp., which are among the most important emerging risks to be assessed in food safety, alone or in combination with other mycotoxins and bioactive food constituents. According to the literature covered, multiple mycotoxins may often occur simultaneously in contaminated food, along with several other mycotoxins and food bioactives inherently present in the studied matrices. Although the toxicity of combinations naturally found in food has been rarely assessed experimentally, the data collected so far, clearly point out that chemical mixtures may differ in their toxicity compared to the effect of toxins tested individually. The data presented here may provide a solid foothold to better support the risk assessment of mycotoxins highlighting the actual role of chemical mixtures on influencing their toxicity.
Topics: Alternaria; Edible Grain; Food Contamination; Fruit; Humans; Mycotoxins; Risk Assessment; Vegetables; Xenobiotics
PubMed: 31684145
DOI: 10.3390/toxins11110640