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Phytopathology Feb 2023Brown and black spots, caused by and species, are important fungal diseases affecting European pear () in orchards. Both fungal genera cause similar symptoms, which...
Brown and black spots, caused by and species, are important fungal diseases affecting European pear () in orchards. Both fungal genera cause similar symptoms, which could favor misidentification, but spp. are increasingly reported due to the changing climatic conditions. In this study, spp. were isolated from symptomatic leaves and fruits of European pear, and their pathogenicity was evaluated on pear fruits from cultivar Abate Fétel, and molecular and chemical characterization were performed. Based on maximum likelihood phylogenetic analysis, 15 of 46 isolates were identified as species complex (AASC), 27 as , and four as sp. Both species were isolated from mature fruits and leaves. In pathogenicity assays on pear fruits, all isolates reproduced the symptoms observed in the field, by both wound inoculation and direct penetration. All but one isolate produced toxins on European pears, including tenuazonic acid and alternariol (89.1% of the isolates), alternariol monomethyl ether (89.1%), altertoxin I (80.4%), altenuene (50.0%), and tentoxin (2.2%). These isolates also produced at least two mycotoxins, and 43.5% produced four mycotoxins, with an average total concentration of the toxins exceeding 7.58 × 10 ng/kg. Our data underline the potential risks for human health related to the high mycotoxin content found on fruits affected by black spot. This study also represents the first report of AASC as an agent of black spot on European pear in Italy.
Topics: Humans; Fruit; Alternaria; Pyrus; Phylogeny; Virulence; Plant Diseases; Mycotoxins
PubMed: 36167507
DOI: 10.1094/PHYTO-03-22-0103-R -
Plant Disease Sep 2021In a recent survey of post-harvest rot pathogens in European pear in Southern Oregon, spp. were frequently isolated from orchard samples of pear flowers and fruits....
In a recent survey of post-harvest rot pathogens in European pear in Southern Oregon, spp. were frequently isolated from orchard samples of pear flowers and fruits. Morphological differences were observed within the isolated cultures. A preliminary NCBI BLAST search analysis using sequences of the ATPase locus across 94 isolates of spp. obtained from pear fruit rots revealed three major sections: sect. , sect. , and sect. . Thirteen isolates were selected based on their genetic and morphological diversity across three sections and were subjected to multilocus phylogenetic analysis using sequences from plasma membrane ATPase, calmodulin, and loci. Within sect. , four isolates and one . isolate were identified; within sections and , one . isolate and two . isolates were identified, respectively. The remaining five isolates could not be identified based on the available sequences for the three loci used in this study. In addition to the phylogenetic analysis, pathogenicity assays revealed differential responses to these isolates on four pear cultivars: Anjou, Bartlett, Comice, and Bosc. Inoculation of isolates within sect. resulted in fruit lesions across all cultivars, with Bosc pear being significantly susceptible ( 0.0001). Isolates within sect. caused rots on Anjou and Bosc pears, while isolates within sect. developed rots on Bosc pear only. This study suggests that there is differential susceptibility of pear cultivars to Alternaria rots, and the severity of post-harvest rot depends on the type of spp. and cultivar predominant in a region.
Topics: Alternaria; Fruit; Oregon; Phylogeny; Pyrus
PubMed: 33434041
DOI: 10.1094/PDIS-10-20-2143-RE -
Journal of the Science of Food and... Dec 2022Diseases such as Alternaria and pests such as leafminer threaten tomato as one of the most widely used agricultural products. These pests and diseases first damage the...
BACKGROUND
Diseases such as Alternaria and pests such as leafminer threaten tomato as one of the most widely used agricultural products. These pests and diseases first damage the leaves of tomatoes, then the flowers, and finally the fruit. Therefore, the damage to the tomato tree must be controlled in its early stages. It is difficult for farmers to distinguish Alternaria disease from leafminer pest at the early and middle stages of their outbreak on tomato leaves. In the present study, 272 tomato leaf images were prepared from the farm of the Vali-e-Asr University of Rafsanjan, including 100 healthy leaves and 172 infected leaves with both Alternaria and leafminer at the initial stages. The image processing technique, texture, neural networks and adaptive network-based fuzzy inference system (ANFIS) classifiers were used to diagnose Alternaria disease and leafminer pest on this dataset.
RESULTS
The results showed that the ANFIS classifier achieved an accuracy of 84.71% when performing an equal error rate, 87.78% in the area under the curve, and 85.23% in 3.26 s on the central processing unit for the segmentation of Alternaria disease and leafminer pest in RGB color space. Also, the accuracy of 90% and 98% were obtained for segmentation and classification on the PlantVillage dataset in YCBCR color space.
CONCLUSION
The present study suggests a high classification accuracy for an intelligent selection of pixel values to train the ANFIS classifier. This classifier has high accuracy and speed, low sensitivity to the light intensity of images, and practical application in diagnosing various diseases and pests on numerous datasets. © 2022 Society of Chemical Industry.
Topics: Fuzzy Logic; Solanum lycopersicum; Alternaria; Neural Networks, Computer; Plant Leaves
PubMed: 35657067
DOI: 10.1002/jsfa.12052 -
Toxins Jul 2021The tomato is one of the most consumed agri-food products in Lebanon. Several fungal pathogens, including species, can infect tomato plants during the whole growing...
The tomato is one of the most consumed agri-food products in Lebanon. Several fungal pathogens, including species, can infect tomato plants during the whole growing cycle. infections cause severe production and economic losses in field and during storage. In addition, species represent a serious toxicological risk since they are able to produce a wide range of mycotoxins, associated with different toxic activities on human and animal health. Several species were detected on tomatoes, among which the most important are , , and . A set of 49 strains isolated from leaves and stems of diseased tomato plants were characterised by using a polyphasic approach. All strains were included in the recently defined phylogenetic section and grouped in three well-separated sub-clades, namely (24 out of 49), (12 out of 49), and morpho-species (12 out of 49). One strain showed high genetic similarity with an reference strain. Chemical analyses showed that most of the strains, cultured on rice, were able to produce alternariol (AOH), alternariol methyl ether (AME), altenuene (ALT) and tenuazonic acid (TA), with values up to 5634, 16,006, 5156, and 4507 mg kg, respectively. In addition, 66% of the strains were able to co-produce simultaneously the four mycotoxins investigated. The pathogenicity test carried out on 10 strains, representative of phylogenetic sub-clades, revealed that they were all pathogenic on tomato fruits. No significant difference among strains was observed, although and strains were slightly more aggressive than morpho-species strains. This paper reports new insights on mycotoxin profiles, genetic variability, and pathogenicity of species on tomatoes.
Topics: Alternaria; Fruit; Lebanon; Solanum lycopersicum; Mycotoxins; Phylogeny; Plant Diseases
PubMed: 34437384
DOI: 10.3390/toxins13080513 -
Journal of Environmental Management Apr 2023Alternaria spores are a common component of the bioaerosol. Many Alternaria species are plant pathogens, and their conidia are catalogued as important aeroallergens....
Alternaria spores are a common component of the bioaerosol. Many Alternaria species are plant pathogens, and their conidia are catalogued as important aeroallergens. Several aerobiological studies showing a strong relationship between concentrations of airborne spore and meteorological parameters have consequently been developed. However, the Alternaria airborne load variation has not been thoroughly investigated because it is difficult to assess their sources, as they are a very common and widely established phytopathogen. The objective of this study is to estimate the impact of vegetation and land uses as potential sources on airborne spore load and to know their influence, particularly, in cases of long-medium distance transport. The daily airborne spore concentration was studied over a 5-year period in León and Valladolid, two localities of Castilla y León (Spain), with differences in their bioclimatic and land use aspects. Moreover, the land use analysis carried out within a 30 km radius of each monitoring station was combined with air mass data in order to search for potential emission sources. The results showed a great spatial variation between the two areas, which are relatively close to each other. The fact that the spore concentrations recorded in Valladolid were higher than those in León was owing to prevailing winds originating from large areas covered by cereal crops, especially during the harvest period. However, the prevailing winds in León came from areas dominated by forest and shrubland, which explains the low airborne spore load, since the main Alternaria sources were the grasslands located next to the trap. Furthermore, the risk days in this location presented an unusual wind direction. This study reveals the importance of land cover and wind speed and direction data for establishing potential airborne routes of spore transport in order to improve the Alternaria forecasting models. The importance of conducting Alternaria aerobiological studies at a local level is also highlighted.
Topics: Wind; Alternaria; Environmental Monitoring; Air Microbiology; Spores, Fungal; Seasons
PubMed: 36731420
DOI: 10.1016/j.jenvman.2023.117414 -
Food and Chemical Toxicology : An... Dec 2023Mycotoxins are secondary metabolites produced by fungi such as Aspergillus, Alternaria, and Penicillium, affecting nearly 80% of global food crops. Tenuazonic acid (TeA)...
Mycotoxins are secondary metabolites produced by fungi such as Aspergillus, Alternaria, and Penicillium, affecting nearly 80% of global food crops. Tenuazonic acid (TeA) is the major mycotoxin produced by Alternaria alternata, a prevalent pathogen affecting plants, fruits, and vegetables. TeA is notably prevalent in European diets, however, TeA biomarkers of exposure and metabolites remain unknown. This research aims to bridge this knowledge-gap by gaining insights about human TeA exposure and metabolization. Nine subjects were divided into two groups. The first group received a single bolus of TeA at the Threshold of Toxicological Concern (TTC) to investigate the presence of TeA urinary biomarkers, while the second group served as a control. Sixty-nine urinary samples were prepared and analyzed using UPLC-Xevo TQ-XS for TeA quantification and UPLC-Orbitrap Exploris for polar metabolome acquisition. TeA was rapidly excreted during the first 13 h and the fraction extracted was 0.39 ± 0.22. The polar metabolome compounds effectively discriminating the two groups were filtered using Orthogonal Partial Least Squares-Discriminant Analysis and subsequently annotated (n = 122) at confidence level 4. Finally, the urinary metabolome was compared to in silico predicted TeA metabolites. Nine metabolites, including oxidized, N-alkylated, desaturated, glucuronidated, and sulfonated forms of TeA were detected.
Topics: Humans; Tenuazonic Acid; Mycotoxins; Fruit; Metabolomics; Crops, Agricultural; Alternaria
PubMed: 37951345
DOI: 10.1016/j.fct.2023.114183 -
Toxins Jan 2023Pathogenic fungi in the genera , , , , , , , , , and are the most common cause of pre- and postharvest diseases of fruit, vegetable, root and grain commodities. Some... (Review)
Review
Pathogenic fungi in the genera , , , , , , , , , and are the most common cause of pre- and postharvest diseases of fruit, vegetable, root and grain commodities. Some species are also able to produce mycotoxins, secondary metabolites having toxic effects on human and non-human animals upon ingestion of contaminated food and feed. Synthetic fungicides still represent the most common tool to control these pathogens. However, long-term application of fungicides has led to unacceptable pollution and may favour the selection of fungicide-resistant mutants. Microbial biocontrol agents may reduce the incidence of toxigenic fungi through a wide array of mechanisms, including competition for the ecological niche, antibiosis, mycoparasitism, and the induction of resistance in the host plant tissues. In recent years, the emission of volatile organic compounds (VOCs) has been proposed as a key mechanism of biocontrol. Their bioactivity and the absence of residues make the use of microbial VOCs a sustainable and effective alternative to synthetic fungicides in the management of postharvest pathogens, particularly in airtight environments. In this review, we will focus on the possibility of applying yeast VOCs in the biocontrol of mycotoxigenic fungi affecting stored food and feed.
Topics: Animals; Mycotoxins; Saccharomyces cerevisiae; Volatile Organic Compounds; Perfume; Fungicides, Industrial; Firearms; Fungi; Alternaria
PubMed: 36668865
DOI: 10.3390/toxins15010045 -
PloS One 2020Managing pests in carrot production is challenging. Endophytic microbes have been demonstrated to improve the health and productivity of many crops, but factors...
Managing pests in carrot production is challenging. Endophytic microbes have been demonstrated to improve the health and productivity of many crops, but factors affecting endophyte dynamics in carrot is still not well understood. The goal of this study was to determine how crop management system and carrot genotype interact to affect the composition and potential of endophytes to mitigate disease caused by Alternaria dauci, an important carrot pathogen. Twenty-eight unique isolates were collected from the taproots of nine diverse genotypes of carrot grown in a long-term trial comparing organic and conventional management. Antagonistic activity was quantified using an in vitro assay, and potential for individual isolates to mitigate disease was evaluated in greenhouse trials using two carrot cultivars. Results confirm that carrot taproots are colonized by an abundant and diverse assortment of bacteria and fungi representing at least distinct 13 genera. Soils in the organic system had greater total organic matter, microbial biomass and activity than the conventional system and endophyte composition in taproots grown in this system were more abundant and diverse, and had greater antagonistic activity. Carrot genotype also affected endophyte abundance as well as potential for individual isolates to affect seed germination, seedling growth and tolerance to A. dauci. The benefits of endophytes on carrot growth were greatest when plants were subject to A. dauci stress, highlighting the importance of environmental conditions in the functional role of endophytes. Results of this study provide evidence that endophytes can play an important role in improving carrot performance and mediating resistance to A. dauci, and it may someday be possible to select for these beneficial plant-microbial relationships in carrot breeding programs. Implementing soil-building practices commonly used in organic farming systems has potential to promote these beneficial relationships and improve the health and productivity of carrot crops.
Topics: Alternaria; Crop Production; Crop Protection; Daucus carota; Endophytes; Genotype; Germination; Plant Diseases; Soil; Soil Microbiology
PubMed: 32497087
DOI: 10.1371/journal.pone.0233783 -
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 -
Plant Disease Feb 2022is a cosmopolitan fungal genus associated with diverse hosts. Tobacco brown spot caused by is one of the most destructive diseases of tobacco. can also infect many...
is a cosmopolitan fungal genus associated with diverse hosts. Tobacco brown spot caused by is one of the most destructive diseases of tobacco. can also infect many other plants, some animals and even humans. Here, we report a genome assembly of CBS 540.94 using Oxford Nanopore Technologies. A total of 15 contigs were assembled, and the genome size was 37.5 Mb with contig N50 of 4.33 Mb. This genome resource will provide information for further research on comparative genomics of the genus and be a valuable resource in investigations of the molecular interactions of pathogen and hosts.
Topics: Alternaria; Animals; Genome, Fungal; Genomics; Plant Diseases; Nicotiana
PubMed: 34597148
DOI: 10.1094/PDIS-06-21-1274-A