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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 -
Journal of Biomolecular Structure &... Mar 2020is a major pathogen for crops like tomato, tangerine and so on and its control is mostly dependent on the application of chemical agents. Plants as the sources of...
is a major pathogen for crops like tomato, tangerine and so on and its control is mostly dependent on the application of chemical agents. Plants as the sources of natural products are very attractive option for developing eco-friendly and natural antifungal agents. In this study, we modeled three-dimensional structure of chorismate synthase (CS) enzyme from . Docking studies of phytosterols, namely, γ-sitosterol and β-sitosterol, with CS showed them to be potential inhibitor of CS. To explore the stability and conformational flexibility of all the complex systems, molecular dynamics simulations were performed. None of the putative inhibitors as well as β- and γ-sitosterol showed interaction with the FMNH binding pocket of the tomato CS (major host of ) indicating their suitability as antifungal compounds inhibiting the shikimate pathway without causing any harm to the host. An antifungal bioassay showed a significant reduction in fungal growth in the presence of β-sitosterol (500 ppm) which resulted in ∼23% and ∼17% reduction in fungal fresh and dry weight, respectively, at 8 days after inoculation. This study provides experimental evidence establishing natural sterols like β-sitosterol can be useful in curbing damage in an eco-friendly manner.Communicated by Ramaswamy H. Sarma.
Topics: Alternaria; Antifungal Agents; Biological Products; Drug Evaluation, Preclinical; Microbial Sensitivity Tests; Models, Molecular; Molecular Conformation; Molecular Dynamics Simulation; Phylogeny; Phytosterols; Structure-Activity Relationship
PubMed: 30898083
DOI: 10.1080/07391102.2019.1597767 -
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 -
Microbiological Research Mar 2022The ability to cope with environmental abiotic stress and biotic stress is crucial for the survival of plants and microorganisms, which enable them to occupy multiple...
The ability to cope with environmental abiotic stress and biotic stress is crucial for the survival of plants and microorganisms, which enable them to occupy multiple niches in the environment. Previous studies have shown that transcription factors play crucial roles in regulating various biological processes including multiple stress tolerance and response in eukaryotes. This work identified multiple critical transcription factor genes, metabolic pathways and gene ontology (GO) terms related to abiotic stress response were broadly activated by analyzing the transcriptome of phytopathogenic fungus Alternaria alternata under metal ions stresses, oxidative stress, salt stresses, and host-pathogen interaction. We investigated the biological functions and regulatory roles of the bZIP transcriptional factor (TF) genes in the phytopathogenic fungus A.alternata by analyzing targeted gene disrupted mutants. Morphological analysis provides evidence that the bZIP transcription factors (Gcn4, MeaB, Atf1, the ER stress regulator Hac1, and the all development altered-1 gene Ada1) are required for morphogenesis as the colony morphology of these gene deletion mutants was significantly different from that of the wild-type. In addition, bZIPs are involved in the resistance to multiple stresses such as oxidative stress (Ada1, Yap1, MetR) and virulence (Hac1, MetR, Yap1, Ada1) at varying degrees. Transcriptome data demonstrated that the inactivation of bZIPs (Hac1, Atf1, Ada1 and Yap1) significantly affected many genes in multiple critical metabolism pathways and gene ontology (GO) terms. Moreover,the ΔHac1 mutants displayed reduced aerial hypha and are hypersensitivity to endoplasmic reticulum disruptors such as tunicamycin and dithiothreitol. Transcriptome analysis showed that inactivation of Hac1 significantly affected the proteasome process and its downstream unfolded protein binding, indicating that Hac1 participates in the endoplasmic reticulum stress response through the conserved unfolded protein response. Taken together, our findings reveal that bZIP transcription factors function as key regulators of fungal morphogenesis, abiotic stress response and pathogenesis, and expand our understanding of how microbial pathogens utilize these genes to deal with environmental stresses and achieve successful infection in the host plant.
Topics: Alternaria; Basic-Leucine Zipper Transcription Factors; Fungal Proteins; Stress, Physiological
PubMed: 34953292
DOI: 10.1016/j.micres.2021.126915 -
Journal of Natural Products Apr 2019The enantiomers (+)- and (-)-alternarilactone A (1), the first examples of dibenzo-α-pyrones bearing a diepoxy-cage-like moiety, were isolated from the endophytic...
The enantiomers (+)- and (-)-alternarilactone A (1), the first examples of dibenzo-α-pyrones bearing a diepoxy-cage-like moiety, were isolated from the endophytic fungus Alternaria sp. hh930. The deficiency in H-H COSY and HMBC correlations caused by the highly oxidized caged system of 1 and the deceptive and ambiguous signals such as "W" couplings in NMR data increased the risk of structure misassignment of 1. By performing a quantum chemical calculation of the NMR chemical shifts together with a DP4+ probability analysis and single-crystal X-ray crystallographic experiment, their structures were unambiguously determined, and their absolute configurations were determined by ECD calculations.
Topics: Alternaria; Chromatography, Liquid; Crystallography, X-Ray; Epoxy Compounds; Spectrum Analysis; Stereoisomerism
PubMed: 30767530
DOI: 10.1021/acs.jnatprod.8b00571 -
Current Microbiology Sep 2020Locoweeds are toxic leguminous plants in Astragalus and Oxytropis genera that contain fungal endophytes of Alternaria section Undifilum species. These fungi produce...
Locoweeds are toxic leguminous plants in Astragalus and Oxytropis genera that contain fungal endophytes of Alternaria section Undifilum species. These fungi produce swainsonine, an alkaloid α-mannosidase inhibitor that causes a neurological syndrome, locoism in grazing animals. A SWN gene cluster has been identified in many swainsonine-producing fungi. The swnK gene, which is an essential component of the swainsonine biosynthetic pathway, encodes a polyketide synthase-nonribosomal peptide synthase (PKS-NRPS). To determine if swnK was conserved among Alternaria section Undifilum endophytes of locoweed, the sequence of the KS region of swnK was compared between various swainsonine-producing fungi. The internal transcribed spacer (ITS), and glyceraldehyde-3-phosphate dehydrogenase (GPD) regions from the same fungi were also assessed. Sequences were examined at the nucleotide and protein levels. Alternaria oxytropis, A. fulva, A. cinerea, and Alternaria sp. from Swainsona species produced distinct clades for all multigene data sets. swnK-KS sequence did not differ among fungi isolated from Astragalus mollissimus varieties or A. lentiginosus varieties. The swnK-KS amino acid sequence was essentially identical among all swainsonine-producing Alternaria sp. Two low swainsonine-producing fungi, Alternaria bornmuelleri and A. gansuense, clustered together, as did non-pathogen Alternaria endophytes. The swnK-KS sequence comparisons were effective in identifying swainsonine production capability and differentiating among swainsonine-producing fungal species.
Topics: Alternaria; Animals; Polyketides; Swainsonine; United States
PubMed: 32647979
DOI: 10.1007/s00284-020-02111-2 -
Journal of Agricultural and Food... Dec 2021sp. infections on apple ( × Borkh.) lead to impaired fruit quality and yield losses by leaf blotches and fruit spots, caused by host-specific toxins (HSTs) of the...
sp. infections on apple ( × Borkh.) lead to impaired fruit quality and yield losses by leaf blotches and fruit spots, caused by host-specific toxins (HSTs) of the apple pathotype like AM-toxins. Fungal isolates were obtained during severe outbreaks on cv. Gala, Golden Delicious, and Cripps Pink/Rosy Glow in South Tyrol and other regions in northern Italy. The isolates were tested for pathogenicity using assays with detached apple leaves. Conidial suspensions of pathogenic isolates were shown to provoke necrotic lesions also in apple seedlings and on fruits. Detached-leaf assay-guided fractionation of the isolates' culture supernatant and a high-resolution liquid chromatography-mass spectrometry (LC-MS) analysis tentatively identified 27 known phytotoxins and a new putative toxin, (3ξ,4ξ,5ξ,6ξ,7ξ,11ξ)-3,6-dihydroxy-8-oxo-9-eremophilene-12-oic acid (). The constitution and the relative configuration of the ring stereocenters of were elucidated by NMR spectroscopy, revealing unique structural features among phytotoxins. Indeed, molecular analysis revealed the lack of the toxin-related genes , , and in all isolates from the region, suggesting that Alternaria apple blotch in the area was associated with another metabolite (.
Topics: Alternaria; Fruit; Malus; Plant Diseases
PubMed: 34808059
DOI: 10.1021/acs.jafc.1c02847 -
World Journal of Microbiology &... May 2019In the present study, an endophytic fungal strain was isolated from its non-Taxus host plant Terminalia arjuna and identified as Alternaria brassicicola based on its...
In the present study, an endophytic fungal strain was isolated from its non-Taxus host plant Terminalia arjuna and identified as Alternaria brassicicola based on its morphological characteristics and internal transcribed spacer sequence analysis. This fungus was grown in potato dextrose broth and analyzed for the presence of taxol by using chromatographic and spectrometric techniques. The ethyl acetate extract of A.brassicicola was subjected to column chromatography. Among the different fractions, the fraction 7 showed positive to taxol, which was further confirmed by UV absorption, HPLC, FTIR spectra and LC-ESI-MS by comparing with the authentic taxol (Paclitaxel). The peaks of fraction 7 obtained by UV spectroscopy, FTIR and HPLC analysis were quite similar to that of standard taxol confirming the presence of taxol. A parent ion peak of m/z 854.95 was observed in the LC-ESI-MS spectrum which was similar to paclitaxel with reported m/z of 854 [M+H] ion. A. brassicicola produced about 140.8 μg/l taxol as quantified through HPLC. Present study results suggest that the endophytic fungus A.brassicicola serves as a potential source for the production of taxol isolated from non-Taxus plant.
Topics: Alternaria; Chromatography; Chromatography, High Pressure Liquid; Endophytes; Fermentation; Mass Spectrometry; Paclitaxel; Plants, Medicinal; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Terminalia
PubMed: 31053977
DOI: 10.1007/s11274-019-2651-8 -
Virus Research Apr 2020The leaf blight caused by the genus Alternaria is one of the most epidemic diseases on watermelon, and A. tenuissima is the dominant pathogenic species in China....
Molecular and biological characterization of a novel strain of Alternaria alternata chrysovirus 1 identified from the pathogen Alternaria tenuissima causing watermelon leaf blight.
The leaf blight caused by the genus Alternaria is one of the most epidemic diseases on watermelon, and A. tenuissima is the dominant pathogenic species in China. Mycoviruses are found ubiquitously in filamentous fungi, and an increasing number of novel mycoviruses infecting the genus Alternaria have been reported. In this study, a mycovirus from A. tenuissima strain SD-BZF-12 was identified and characterized, whose genome size was very similar with Alternaria alternata chrysovirus 1-N18 (AaCV1-N18). The dsRNA1- and dsRNA2-encoded proteins of the virus had 99 % identities with counterparts of AaCV1-N18; and the dsRNA3- and dsRNA4-encoded proteins of the virus showed the 80 % and 94 % sequence identities with proteins deduced from dsRNA4 and dsRNA3 of AaCV1-N18, respectively. Intriguingly, dsRNA5 of the virus encoded a truncated protein with 68 amino acids (aa) by comparing with 115 aa of AaCV1-N18 dsRNA5. Phylogenetic analysis of RNA-dependent RNA polymerase domain suggested that the virus clustered together with AaCV1-N18. Based on these characteristics, the mycovirus was identified to be a novel strain of AaCV1 and designated as AaCV1-AT1. In addition, no obvious differences were observed on colony morphology between AaCV1-AT1-infected and virus-cured strains of A. tenuissima; however, AaCV1-AT1 infection reduced colony growth rate and spore production ability on host fungus, and increased the median effective concentration of difenoconazole or tebuconazole on its host. This is the first report of AaCV1-AT1 associated with A. tenuissima.
Topics: Alternaria; China; Citrullus; Fungal Viruses; Genome, Viral; Open Reading Frames; Phylogeny; Plant Diseases; RNA, Viral; Viral Proteins
PubMed: 32105762
DOI: 10.1016/j.virusres.2020.197904 -
Journal of Applied Microbiology Nov 2021To report the characterization of 120 Alternaria isolates inducing early blight-like foliar lesions in nine species of five Solanaceae genera collected across all...
Species diversity, novel interactions and absence of well-supported host-guided phylogenetic groupings of Neotropical Alternaria isolates causing foliar lesions in Solanaceae.
AIM
To report the characterization of 120 Alternaria isolates inducing early blight-like foliar lesions in nine species of five Solanaceae genera collected across all macrogeographical Brazilian regions.
MATERIAL AND RESULTS
Phylogenetic relationships were assessed via analyses of the Alternaria alternata allergenic protein-coding, glyceraldehyde-3-phosphate dehydrogenase and the calmodulin gene sequences. Most of the tomato isolates were placed into the Alternaria linariae cluster, whereas most of the potato isolates were grouped with Alternaria grandis. Novel host-pathogen interactions were also reported. Seventeen isolates were selected for morphometrical characterization, and a subsample of 13 isolates was employed in pathogenicity assays on tomato, potato, eggplant, scarlet eggplant, Capsicum annuum, Datura stramonium, Physalis angulata and Nicotiana tabacum. Eleven isolates were able to induce foliar lesions in tomatoes but none in C. annuum. Potato was susceptible to a subgroup of isolates but displayed a subset of isolate-specific interactions. Morphological traits were in overall agreement with molecular and host range data.
CONCLUSION
Alternaria linariae and A. grandis were confirmed as the major causal agents of tomato and potato early blight, respectively. However other Alternaria species are also involved with early blight in solanaceous hosts in Brazil.
SIGNIFICANCE AND IMPACT OF THE STUDY
The diversity and host-specific patterns of the Alternaria isolates from Solanaceae may have practical implications in establishing effective early blight genetic resistance and cultural management strategies especially for tomato and potato crops.
Topics: Alternaria; Phylogeny; Plant Diseases; Solanum tuberosum
PubMed: 33891782
DOI: 10.1111/jam.15115