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Molecular Plant-microbe Interactions :... Jul 2021Species of (phylum Ascomycota, family Pleosporaceae) are known as serious plant pathogens, causing major losses on a wide range of crops. (previously known as ) can...
Species of (phylum Ascomycota, family Pleosporaceae) are known as serious plant pathogens, causing major losses on a wide range of crops. (previously known as ) can grow as a saprophyte on many hosts and causes Ulocladium blight on potato. It has been reported that it can also be used as a biocontrol agent against . Here, we present a scaffold-level reference genome assembly for The assembly contains 43 scaffolds with a total length of 39.62 Mbp, with scaffold N of 3,893,166 bp, L of 4, and the longest 10 scaffolds containing 89.9% of the assembled data. RNAsequencing-guided gene prediction using BRAKER resulted in 12,173 protein-coding genes with their functional annotation. This first high-quality reference genome assembly and annotation for can be used as a resource for studying evolution in the highly complicated genus and might help in understanding the mechanisms defining its role as pathogen or biocontrol agent.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
Topics: Alternaria; Ascomycota; Botrytis; Molecular Sequence Annotation; Solanum tuberosum
PubMed: 33779266
DOI: 10.1094/MPMI-01-21-0016-A -
Plant Disease Jan 2021Watermelon is an economically important crop in China and is commonly affected by -like leaf blight that can result in significant economic losses. In this study, 830...
Watermelon is an economically important crop in China and is commonly affected by -like leaf blight that can result in significant economic losses. In this study, 830 isolates, recovered from symptomatic watermelon leaves, were identified based on morphological traits, pathogenicity, and multilocus sequence analyses of glyceraldehyde-3-phosphate dehydrogenase (), histone 3 (), the internal transcribed spacer of ribosomal DNA (rDNA ITS), and the RNA polymerase II second largest subunit (). Watermelon isolates grouped to five species and one unclassified species. They were , , , , , and sp. Notably, was the most prevalent (73.5%) of the six isolated species, followed by (25.0%), (1.1%), sp. (0.2%), (0.1%), and (0.1%). Pathogenicity tests demonstrated that all six species could produce brown necrotic lesions on detached leaves of watermelon. The average disease incidence (75.1%) and average disease index (60.8) of watermelon resulting from inoculation of leaves with were significantly higher than levels resulting from (52.9% and 37.2) and (47.5% and 30.8). Inoculation with sp. resulted in a disease incidence (70.0%) and disease index (51.5), which were lower than those of . The disease incidence and disease index in watermelon leaves inoculated with the one isolate of and the one isolate of present in the inoculated leaves were 28.9% and 16.4, and 48.9% and 31.4, respectively. Results of the study indicate that species associated with watermelon leaf blight in China are more diverse than that has been previously reported. This is the first report globally of , , and an unclassified species as causal agents of leaf blight on watermelon.
Topics: Alternaria; China; Citrullus; Multilocus Sequence Typing; Phylogeny
PubMed: 33170772
DOI: 10.1094/PDIS-01-20-0130-RE -
Food Additives & Contaminants. Part B,... Mar 2022The collection of occurrence data on toxins in food and feed across the European countries is required since 2012 by the European Commission, endorsing the relevant...
The collection of occurrence data on toxins in food and feed across the European countries is required since 2012 by the European Commission, endorsing the relevant scientific opinion by the EFSA CONTAM Panel. Within this framework, occurrence data for toxins (Alternariol, Alternariol monomethyl ether, Tenuazonic acid, Tentoxin, and Altenuene) in 97 samples of cereal foods, tomato products, and sunflower seeds have been provided as requested by the Italian national monitoring programme (years 2017-2020). To this purpose, an LC-MS/MS method was set up and validated, obtaining fit for purpose sensitivity, recoveries (70-120%), repeatability (≤20%) and within laboratory reproducibility (≤26%). Occurrence data showed that oilseeds were the most contaminated food group with levels of Tenuazonic acid up to 16752 µg/kg and Tentoxin up to 570 µg/kg, whereas for the other mycotoxin/commodities combinations, the percentage of left censored data (below the limit of quantification) ranged from 74 to 100%.
Topics: Alternaria; Chromatography, Liquid; Food Contamination; Mycotoxins; Reproducibility of Results; Tandem Mass Spectrometry
PubMed: 34895088
DOI: 10.1080/19393210.2021.2000505 -
Isolation and identification of Tussilago farfara leaf spot caused by Alternaria alternata in China.Microbial Pathogenesis Nov 2022Tussilago farfara is of vital medical value. A new leaf spot disease was observed on T. farfara leaves, in Dingxi, Gansu Province, China, in October 2019. In order to...
Tussilago farfara is of vital medical value. A new leaf spot disease was observed on T. farfara leaves, in Dingxi, Gansu Province, China, in October 2019. In order to research the pathogen, the diseased samples were collected for isolation and identification. The isolate KD3 was verified by pathogenicity test, as the pathogen causing the T. farfara leaf spot disease. Its morphological characteristics were consistent with Alternaria alternata, the colony color gray-green with concentric rings, conidia fusiform and pear-shaped, brown, with 1-7 septa and 0-3 longitudinal septa, conidia size (19. 62-44.49) μm × (6.97-10.53) μm, beak length (1.35-10.03) μm × (1.01-3.63) μm, and the spore phenotype was a dwarf tree-like chain of short conidia. Multilocus sequences analysis manifested that the internal transcribed spacer (ITS), Alternaria major allergen (Alta1), and Calcium barine (CAL) sequences of strain KD3 were most closely to A. alternata (A23), with the homology of 99.47%, 99.56% and 98.28%, respectively. Based on morphological and molecular characteristics, strain KD3 was identified as A. alternata. OA was the optimal medium for its growth and PCA medium was the optimal for sporulation. This is the first report of A. alternata causing T. farfara leaf spots in China.
Topics: Alternaria; Tussilago; Calcium; China; Allergens
PubMed: 36075342
DOI: 10.1016/j.micpath.2022.105750 -
Pesticide Biochemistry and Physiology Jun 2021Vanillin is a natural antimicrobial agent; however, there are few reports on its antifungal effect on postharvest pathogenic fungi. This study aimed to investigate the...
Vanillin is a natural antimicrobial agent; however, there are few reports on its antifungal effect on postharvest pathogenic fungi. This study aimed to investigate the in vivo and in vitro antifungal activities of vanillin against gray mold (caused by B. cinerea) and black rot (caused by A. alternata) of cherry tomato fruit and to explain its possible mechanism of action. Vanillin strongly inhibits Botrytis cinerea and Alternaria alternata mycelial growth, spore germination, and germ tube elongation in a concentration-dependent manner (P<0.05). In vivo experiments showed that 4000 mg L vanillin treatment inhibited cherry tomato gray mold and black rot occurrence. Besides, intercellular electrolytes, soluble proteins, and soluble sugars leakage indicated that 50 or 100 mg L vanillin treatment increased Botrytis cinerea and Alternaria alternata membrane permeability. The increase of malondialdehyde and hydrogen peroxide contents confirmed that 50 or 100 mg L vanillin treatment damages the pathogen membranes. Importantly, vanillin treatment inhibited the pathogenicity-related enzyme activities of the two pathogens to reduce their infection ability, among them PL enzyme activity in A. alternata was most inhibited, reducing by 94.7 % at 6 h treated with 100 mg L vanillin. The hyphae morphology of the two pathogens changed, the mycelia were severely damaged, and the hyphae surface was deformed, shrunk, or even broken after 100 mg L vanillin treatment. In summary, vanillin had a substantial inhibitory effect on postharvest gray mold and black rot in cherry tomato fruit. Therefore, vanillin can be an effective alternative to prevent and control cherry tomato postharvest diseases.
Topics: Alternaria; Benzaldehydes; Botrytis; Fruit; Solanum lycopersicum; Plant Diseases
PubMed: 33993955
DOI: 10.1016/j.pestbp.2021.104859 -
Plant Disease May 2023Alternaria leaf blight and head rot is an important disease of broccoli and other cole crops. With no resistant host varieties, fungicides are utilized to manage this...
Alternaria leaf blight and head rot is an important disease of broccoli and other cole crops. With no resistant host varieties, fungicides are utilized to manage this disease. However, anecdotal evidence suggests that, in southeastern U.S. broccoli-producing states, there is a loss of disease control through the use of quinone outside inhibitor (QoI) fungicides. To understand why there is a reduced sensitivity to QoI fungicides in these states, we isolated spp. from symptomatic lesions on cole crops from Georgia and Virginia (two states with observations of loss of fungicide sensitivity) as well as New York (a state with no observations of loss of fungicide sensitivity). Using multilocus sequencing and phylogenetic analysis, we identified two species, and . Whereas was isolated in all states, was only isolated in Georgia. Next, we wanted to determine the sensitivity of these isolates to azoxystrobin-an active ingredient in some QoI fungicides-by estimating the effective concentration at which only 50% of spores germinate (EC). The EC of ranged from 0.01 to 0.17 ppm, whereas that of was 8.1 to 28.1 ppm. None of the known target-site mutations that confer resistance to QoI fungicides were identified during screening of either species. was first reported on the east coast of the United States in 2020 in South Carolina. The substantially higher EC value suggests that its emergence in the southeastern United States may play at least a part in the observed loss of disease control. However, further in planta and field studies are needed to thoroughly test this hypothesis.
Topics: United States; Fungicides, Industrial; Alternaria; Phylogeny; New York; Georgia
PubMed: 36324201
DOI: 10.1094/PDIS-06-22-1318-SC -
Mycotoxin Research May 2020Fluorescent pseudomonads colonizing wheat ears have a high antagonistic potential against phytopathogenic fungi. To check this hypothesis, the bacterial antagonist...
Fluorescent pseudomonads colonizing wheat ears have a high antagonistic potential against phytopathogenic fungi. To check this hypothesis, the bacterial antagonist Pseudomonas simiae 9 was spray-inoculated onto the ears of winter wheat in a locally demarcated experimental field plot. Fusarium and Alternaria fungi naturally occurring on the ears and the formation of their mycotoxins in the ripe grains were investigated. Inoculated bacteria were recovered from the plants in the inoculation cell, but not in the untreated neighboring plots or in the air above the plants. Growth of fusaria and alternaria on the ears was not influenced by the bacterial antagonist. Wheat kernels were co-inoculated in vitro with the antagonist and one mycotoxin-producing strain of Fusarium and Alternaria, respectively. Mycotoxin production was almost completely suppressed in these approaches. Concentrations of zearalenone, deoxynivalenol, alternariol, and tenuazonic acid were also significantly reduced in ripe grains in the field, but to a lesser extent than in vitro. The results of this and previous studies suggest that widespread biological control of the growth of fusaria and alternaria and their mycotoxin formation by naturally occurring pseudomonads with antagonistic activity is rather unlikely.
Topics: Alternaria; Antibiosis; Biological Control Agents; Fusarium; Lactones; Mycotoxins; Pseudomonas; Tenuazonic Acid; Trichothecenes; Triticum; Zearalenone
PubMed: 31755073
DOI: 10.1007/s12550-019-00379-3 -
Plant Disease May 2022Alternaria rot caused by is one of the major postharvest diseases affecting blueberries in California. The sensitivity profiles of . from blueberry field to quinone...
Alternaria rot caused by is one of the major postharvest diseases affecting blueberries in California. The sensitivity profiles of . from blueberry field to quinone outside inhibitors (QoIs), boscalid, fluopyram, fludioxonil, cyprodinil, and polyoxin D in California were examined in this study. EC values of 51 . isolates for boscalid varied greatly among the isolates, ranging from 0.265 to >100 μg/ml. EC values of 51 . isolates to fluopyram, fludioxonil, cyprodinil, and polyoxin D were 5.188 ± 7.118, 0.078 ± 0.021, 0.465 ± 0.302, and 6.238 ± 7.352 μg/ml, respectively. In total, 143 isolates were screened for resistance at 5 and 10 μg/ml for fludioxonil, cyprodinil, and fluopyram, 10 μg/ml for polyoxin D, and 10 and 50 μg/ml for boscalid. Based on the published discriminatory concentrations for phenotyping resistance, of the 143 isolates, all were considered resistant to boscalid; 32, 69, and 42 were sensitive, low resistant, and resistant to fluopyram, respectively; and all were sensitive to fludioxonil and cyprodinil. In a PCR-restriction fragment length polymorphism method for phenotyping, 60 out of the 143 isolates were classified as resistant to QoIs. Control tests on detached blueberry fruit inoculated with different isolates showed that fludioxonil and cyprodinil significantly reduced disease incidence and severity; however, pyraclostrobin, boscalid, fluopyram, and polyoxin D significantly reduced only disease severity. The obtained results will be helpful in making decisions on fungicide programs to control . isolates with resistance or reduced sensitivities to multiple fungicides.
Topics: Alternaria; Blueberry Plants; Fruit; Fungicides, Industrial
PubMed: 34874181
DOI: 10.1094/PDIS-09-21-1971-RE -
Toxins Apr 2020Black point is a fungal disease of wheat, mainly associated with mycotoxigenic species. Affected wheat kernels are characterized by dark brown discolouration of the...
Black point is a fungal disease of wheat, mainly associated with mycotoxigenic species. Affected wheat kernels are characterized by dark brown discolouration of the embryo region and reduction of grain quality. Potential risk is the possible accumulation of mycotoxins, alternariol (AOH), alternariol-monomethyl ether (AME), tenuazonic acid (TA), and altenuene (ALT), provided by haemato-toxic, genotoxic, and mutagenic activities. One hundred and twenty durum wheat samples belonging to 30 different genotypes grown in Bologna and Modena areas, in Italy, showing black point symptoms, were analyzed for species and their mycotoxin contamination. Alternariol was selected as an indicator of the capability of the species to produce mycotoxin in vivo in field conditions. The data showed that species occurred in 118 out of 120 wheat kernels samples, with the incidence of infected kernels ranging between 1% and 26%. Moreover, AOH was detected by using a HPLC with a diode array detector (LC-DAD) in 98 out of 120 samples with values ranging between 24 and 262 µg Kg. Ninety-two representative strains, previously identified morphologically, were identified at species/section level using gene sequencing, and therefore were analyzed for their mycotoxin profiles. Eighty-four strains, phylogenetically grouped in the section, produced AOH, AME, and TA with values up to 8064, 14,341, and 3683 µg g, respectively, analyzed by using a LC-DAD. On the other hand, eight strains, included in Section, showed a very low or no capability to produce mycotoxins.
Topics: Alternaria; Edible Grain; Environmental Monitoring; Food Contamination; Italy; Mycotoxins; Phylogeny; Plant Diseases; Triticum
PubMed: 32340279
DOI: 10.3390/toxins12040275 -
Toxins Nov 2022mycotoxins including alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT), altertoxin-I (ATX-I), tentoxin (TEN), and tenuazonic acid (TeA), are...
mycotoxins including alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT), altertoxin-I (ATX-I), tentoxin (TEN), and tenuazonic acid (TeA), are ubiquitous contaminants in agricultural products. A method for the simultaneous determination of these six toxins by ultrahigh performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) with solid phase extraction (SPE) was validated in rice, sesame, tomato, and apple juice matrices. The performance of the method was evaluated in terms of linearity ( > 0.999), the limit of detection (0.04-1.67 μg/kg), the limit of quantification (0.12-5.06 μg/kg), recovery (80.0-114.7%), and precision (<17.7%). The validated method was applied to monitor 152 marketed food samples in South Korea, as well as to investigate the co-occurrence and correlation between toxins. The mean occurrence levels were 2.77 μg/kg for AOH, 4.36 μg/kg for AME, 0.14 μg/kg for ALT, 0.11 μg/kg for ATX-I, 0.43 μg/kg for TEN, and 104.56 μg/kg for TeA. Mean and extreme (95th percentile) daily dietary exposures of South Koreans to toxins were estimated to be 22.93 ng/kg b.w./day and 86.07 ng/kg b.w./day, respectively.
Topics: Humans; Chromatography, Liquid; Alternaria; Tandem Mass Spectrometry; Food, Processed; Food Contamination; Chromatography, High Pressure Liquid; Mycotoxins; Tenuazonic Acid; Lactones
PubMed: 36548721
DOI: 10.3390/toxins14120824