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Journal of Zhejiang University.... Feb 2012The search for active toxins for managing weeds or plant diseases is believed to be a promising avenue of investigation. However, the effects of Alternaria toxins on...
The search for active toxins for managing weeds or plant diseases is believed to be a promising avenue of investigation. However, the effects of Alternaria toxins on insects have just begun to be investigated. Bioactivities of toxins from four strains of Alternaria alternata on Rosa chinensis and rose aphid Macrosiphum rosivorum were tested in the present study. At a concentration of 50.0 μg/ml, the crude extract (toxin) of strain 7484 was found not to be harmful to rose plants with excised leaf-puncture method (P≥0.079), and rose plants showed enhanced resistance to rose aphids when this Alternaria toxin was sprayed on the plants (P≤0.001). However, this toxin caused no detrimental effects on aphids in insecticidal bioassay at a concentration of 10.0 to 160.0 μg/ml (P≥0.096). Therefore, the Alternaria toxin had significantly induced the resistance of rose plants against rose aphids, demonstrating that the resistance mechanism triggered by the Alternaria toxin in the rose plant may also be used by the plant to defend itself against insects. Further bioassays aimed to discover the olfactory responses of aphids to the toxin-induced volatiles of host plants. The aphids were significantly more attracted to both volatiles emitted and collected from control rose plants than to both volatiles emitted and collected from the toxin-treated rose plants (P≤0.014). This result showed that the toxin-induced resistance related to the volatile changes of host plants.
Topics: Alternaria; Animals; Aphids; Biological Assay; Mycotoxins; Plant Diseases; Rosa
PubMed: 22302426
DOI: 10.1631/jzus.B1100087 -
Toxins Nov 2018Wheat, the main source of carbohydrates worldwide, can be attacked by a wide number of phytopathogenic fungi, included species. species commonly occur on wheat...
Wheat, the main source of carbohydrates worldwide, can be attacked by a wide number of phytopathogenic fungi, included species. species commonly occur on wheat worldwide and produce several mycotoxins such as tenuazonic acid (TA), alternariol (AOH), alternariol-monomethyl ether (AME), and altenuene (ALT), provided of haemato-toxic, genotoxic, and mutagenic activities. The contamination by species of wheat kernels, collected in Tuscany, Italy, from 2013 to 2016, was evaluated. contamination was detected in 93 out of 100 field samples, with values ranging between 1 and 73% (mean of 18%). Selected strains were genetically characterized by multi-locus gene sequencing approach through combined sequences of allergen alt1a, glyceraldeyde-3-phosphate dehydrogenase, and translation elongation factor 1α genes. Two well defined groups were generated; namely sections and . Representative strains were analyzed for mycotoxin production. A different mycotoxin profile between the sections was shown. Of the 54 strains analyzed for mycotoxins, all strains included in Section produced AOH and AME, 40 strains (99%) produced TA, and 26 strains (63%) produced ALT. On the other hand, only a very low capability to produce both AOH and AME was recorded among the Section strains. These data show that a potential mycotoxin risk related to the consumption of contaminated wheat is high.
Topics: Alternaria; DNA, Fungal; Food Contamination; Italy; Mycotoxins; Phylogeny; Triticum
PubMed: 30441835
DOI: 10.3390/toxins10110472 -
Mycopathologia Mar 2012In this study, three different rat hybridoma cell lines secreting monoclonal antibodies (mAbs) recognizing the spores from Alternaria alternata, a plant pathogenic...
In this study, three different rat hybridoma cell lines secreting monoclonal antibodies (mAbs) recognizing the spores from Alternaria alternata, a plant pathogenic fungus, contaminant of food products and important cause of both allergic rhinitis and asthma, have been characterized. These three mAbs are all of IgM isotype. Two antibodies, A1 and F10, were cross-reactive antibodies recognizing spores from Alternaria, Cladosporium, Penicillium, Aspergillus and Stachybotrys genera, but not the yeasts Saccharomyces cerevisiae or Candida albicans. Competitive and sandwich assays demonstrated that these two mAbs were directed against the same or very close repetitive(s) epitope(s). A1-based sandwich ELISA efficiently detected this epitope in various mould (but not yeast)-soluble extracts prepared from strains grown in the laboratory. Moreover, this A1-based sandwich ELISA detected its cognate epitope in air and dust samples obtained from dwellings. The third antibody, E5, recognized only the spores of Alternaria and the phylogenetically very close Ulocladium botrytis. This E5 antibody is directed against a repetitive epitope found in Alternaria and Ulocladium laboratory extracts and can be used in a sandwich assay for the quantification of these moulds. Therefore, E5 antibody is a promising tool for the development of Alternaria-Ulocladium-specific immunoassays, while A1 and F10 could be interesting tools for the quantification of the total mould biomass.
Topics: Air Microbiology; Alternaria; Alternariosis; Animals; Antibodies, Fungal; Antibodies, Monoclonal; Antibody Specificity; Cross Reactions; Enzyme-Linked Immunosorbent Assay; Female; Rats
PubMed: 21892786
DOI: 10.1007/s11046-011-9466-y -
Magnetic Resonance in Chemistry : MRC Jan 2021Swainsonine (SW, 1), a unique indolizine with poly-hydroxyl groups, was re-isolated from the plant endophytic fungus Alternaria oxytropis. The structure (including...
Swainsonine (SW, 1), a unique indolizine with poly-hydroxyl groups, was re-isolated from the plant endophytic fungus Alternaria oxytropis. The structure (including planar structure and relative configuration) was systematically elucidated by NMR spectra (including H, C, H- H COSY, HMQC, HMBC, and NOESY spectra in DMSO-d and in CD OD); H NMR spectra of the modified Mosher's products were first used to determine the absolute configuration of SW. More importantly, the complex coupled features of H-7α, H-7β, and H-6α in the H NMR spectrum of (1) were analyzed in details, which will provide aids for the planar and relative configuration determination of analogs.
Topics: Alternaria; Magnetic Resonance Spectroscopy; Mycotoxins; Swainsonine
PubMed: 32910519
DOI: 10.1002/mrc.5098 -
BMC Microbiology Sep 2019Cross-resistance, a phenomenon that a pathogen resists to one antimicrobial compound also resists to one or several other compounds, is one of major threats to human...
BACKGROUND
Cross-resistance, a phenomenon that a pathogen resists to one antimicrobial compound also resists to one or several other compounds, is one of major threats to human health and sustainable food production. It usually occurs among antimicrobial compounds sharing the mode of action. In this study, we determined the sensitivity profiles of Alternaria alternata, a fungal pathogen which can cause diseases in many crops to two fungicides (mancozeb and difenoconazole) with different mode of action using a large number of isolates (234) collected from seven potato fields across China.
RESULTS
We found that pathogens could also develop cross resistance to fungicides with different modes of action as indicated by a strong positive correlation between mancozeb and difenoconazole tolerances to A. alternata. We also found a positive association between mancozeb tolerance and aggressiveness of A. alternata, suggesting no fitness penalty of developing mancozeb resistance in the pathogen and hypothesize that mechanisms such as antimicrobial compound efflux and detoxification that limit intercellular accumulation of natural/synthetic chemicals in pathogens might account for the cross-resistance and the positive association between pathogen aggressiveness and mancozeb tolerance.
CONCLUSIONS
The detection of cross-resistance among different classes of fungicides suggests that the mode of action alone may not be an adequate sole criterion to determine what components to use in the mixture and/or rotation of fungicides in agricultural and medical sects. Similarly, the observation of a positive association between the pathogen's aggressiveness and tolerance to mancozeb suggests that intensive application of site non-specific fungicides might simultaneously lead to reduced fungicide resistance and enhanced ability to cause diseases in pathogen populations, thereby posing a greater threat to agricultural production and human health. In this case, the use of evolutionary principles in closely monitoring populations and the use of appropriate fungicide applications are important for effective use of the fungicides and durable infectious disease management.
Topics: Alternaria; China; Dioxolanes; Drug Resistance, Fungal; Fungicides, Industrial; Maneb; Plant Diseases; Solanum tuberosum; Triazoles; Zineb
PubMed: 31477005
DOI: 10.1186/s12866-019-1574-8 -
Plant Disease Nov 2018Moldy core (MC) of apple is an important disease in Chile, with prevalence observed between 4 and 46% in Fuji, Oregon Spur Red Chief, and Scarlet apple in the 2014-15...
Moldy core (MC) of apple is an important disease in Chile, with prevalence observed between 4 and 46% in Fuji, Oregon Spur Red Chief, and Scarlet apple in the 2014-15 and 2015-16 growing seasons. However, there is no information on the identity of the causal agents associated with MC in Chile. The analysis of 653 MC fruit revealed the presence of several genera of filamentous fungi. However, species of Alternaria (67.7%) were by far the most frequently fungi isolated. In total, 41 Alternaria isolates were characterized morphologically and molecularly using Alternaria major allergen Alt a1, calmodulin, and plasma membrane ATPase gene regions. Six small-spored Alternaria spp. were identified; namely, in order of importance, Alternaria tenuissima, A. arborescens, A. alternata, and A. dumosa in sect. Alternaria; A. frumenti in sect. Infectoriae; and A. kordkuyana in sect. Pseudoalternaria. MC symptoms were reproducible and consisted of a light gray to dark olive-green mycelium over the carpel and seed of immature and mature fruit, confirming that the isolates of these Alternaria spp. were pathogenic. These isolates caused brown necrotic lesions with concentric rings on wounded detached apple leaves. This study demonstrated that at least six Alternaria spp. are the cause of MC of apple in Chile. These Alternaria spp. were isolated alone, or with two or more species coexisting in the same fruit. This is the first report of A. tenuissima, A. arborescens, A. frumenti, A. dumosa, and A. kordkuyana associated with MC of apple in Chile and the first report of A. frumenti, A. kordkuyana, and A. dumosa causing MC of apple worldwide.
Topics: Alternaria; Chile; Fruit; Geography; Malus; Mycelium; Phylogeny; Plant Diseases; Plant Leaves; Polymerase Chain Reaction; Sequence Analysis, DNA; Spores, Fungal
PubMed: 30252624
DOI: 10.1094/PDIS-02-18-0282-RE -
Scientific Reports Sep 2018Alternaria Leaf Blight (ALB), caused by the fungus Alternaria dauci, is the most damaging foliar disease affecting carrots (Daucus carota). In order to identify...
Alternaria Leaf Blight (ALB), caused by the fungus Alternaria dauci, is the most damaging foliar disease affecting carrots (Daucus carota). In order to identify compounds potentially linked to the resistance to A. dauci, we have used a combination of targeted and non-targeted metabolomics to compare the leaf metabolome of four carrot genotypes with different resistance levels. Targeted analyses were focused on terpene volatiles, while total leaf methanolic extracts were subjected to non-targeted analyses using liquid chromatography couple to high-resolution mass spectrometry. Differences in the accumulation of major metabolites were highlighted among genotypes and some of these metabolites were identified as potentially involved in resistance or susceptibility. A bulk segregant analysis on F3 progenies obtained from a cross between one of the resistant genotypes and a susceptible one, confirmed or refuted the hypothesis that the metabolites differentially accumulated by these two parents could be linked to resistance.
Topics: Alternaria; Daucus carota; Genotype; Metabolome; Plant Diseases; Plant Leaves; Secondary Metabolism
PubMed: 30213972
DOI: 10.1038/s41598-018-31700-2 -
Environmental Science and Pollution... Jan 2018The saprotrophic fungus Alternaria alternata is widespread in the agro-environment and produces more than ten allergenic proteins, mostly protein Alt a 1. The frequency...
The saprotrophic fungus Alternaria alternata is widespread in the agro-environment and produces more than ten allergenic proteins, mostly protein Alt a 1. The frequency of the Alt a 1 gene was analyzed in a group of A. alternata isolates from winter wheat kernels obtained in Poland, and the effectiveness of various fungicides targeting the pathogen was evaluated. The Alt a 1 gene was identified in four of the seven tested isolates. A. alternata colonized 35.67% kernels on average, but its frequency increased in stored grain where the presence of epiphytes was noted on 23.09 to 51.38% kernels, and endophytes-in 26.21 to 42.01% of kernels. The efficacy of field-applied fungicides did not exceed 50%, despite the fact that A. alternata is highly sensitive to propiconazole, fenpropimorph, and tebuconazole under in vitro conditions. The analyzed isolates were characterized by limited sensitivity to azoxystrobin (EC ranged from 0.505 to 1.350 μg cm) due to a mutation at codon 143 of the CYT b gene, responsible for resistance to quinone outside inhibitor fungicides, which was noted in all isolates. The spread of A. alternata can be effectively controlled with suitable fungicides and by monitoring the prevalence of pathogenic isolates in the environment.
Topics: Allergens; Alternaria; Cytochromes b; Drug Resistance, Fungal; Fungicides, Industrial; Mutation; Poland; Pyrimidines; Strobilurins; Triticum
PubMed: 29043591
DOI: 10.1007/s11356-017-0426-z -
Plant Disease Apr 2022
Topics: Alternaria; China; Yucca
PubMed: 34491098
DOI: 10.1094/PDIS-04-21-0857-PDN -
Plant Disease May 2021Black spot caused by (BSAA) is one of the most common diseases of var. , causing yield losses in China. Demethylation inhibitors (DMIs) have been used to control this...
Black spot caused by (BSAA) is one of the most common diseases of var. , causing yield losses in China. Demethylation inhibitors (DMIs) have been used to control this disease in China for decades. Some farmers have complained about the decreased efficacy of DMIs against BSAA. The objective of this study was to detect and characterize the resistance of against difenoconazole from var. during 2018. Of the 22 isolates of obtained from Sichuan Province in the southwest of China, 20 were resistant to difenoconazole. Mycelial growth rates and sporulation of the difenoconazole-resistant (Dfn) isolates were not different from those of the difenoconazole-sensitive (Dfn) isolates. No cross resistance between difenoconazole and tebuconazole or propiconazole was observed. Mutations were identified at gene of Dfn isolates based on the sequence alignment of the Dfn and Dfn isolates. All of the mutations could be divided into three resistant genotypes, I (K715R + Y781C), II (K715R + D1140G + T1628A), and III (no mutation). The docking total score of the Dfn isolates was 5.6020, higher than the resistant genotype I (4.4599) or the resistant genotype II (3.8651), suggesting that the DMI resistance of may be caused by the decreased affinity between AaCYP51 and difenoconazole.
Topics: Alternaria; Dioxolanes; Liliaceae; Plants, Medicinal; Triazoles
PubMed: 33349004
DOI: 10.1094/PDIS-12-19-2699-RE