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Journal of Fungi (Basel, Switzerland) Mar 2024Lamb. is an important, common afforestation and timber tree species in China. Species of are well-known pathogens of needle blight. In this study, the five...
Lamb. is an important, common afforestation and timber tree species in China. Species of are well-known pathogens of needle blight. In this study, the five representative strains were isolated from needle blight from needles of in Nanjing, Jiangsu, China. Based on multi-locus phylogenetic analyses of the three genomic loci (ITS, , and ), in conjunction with morphological characteristics, a new species, namely sp. nov., was described and reported. Pathogenicity tests revealed that the five representative strains of the species described above were pathogenic to . The study revealed the diversity of pathogenic species of needle blight on . This is the first report of needle blight caused by on in China and worldwide. This provides useful information for future research on management strategies of this disease.
PubMed: 38535238
DOI: 10.3390/jof10030230 -
Plant Disease May 2024In October 2023, a Connecticut grower contacted The Connecticut Agricultural Experiment Station about a field of strawberry plants ( × ) (cv. Ruby June) showing...
In October 2023, a Connecticut grower contacted The Connecticut Agricultural Experiment Station about a field of strawberry plants ( × ) (cv. Ruby June) showing symptoms of severe leaf spotting and visual wilting. Upon visiting the field, leaves had lesions with a diffuse black halo and a light brown center and wilting symptoms, which appeared driven by petiole lesions and presented as dark brown stripes with a reddish-purple halo. Symptoms were observed on 80 to 90% of plants within the block, nearly all of which (>90%) presented with both leaf spots and severe wilting. Diseased tissue was collected from 20 leaves and 25 petioles, sterilized in 0.6% NaOCL, and plated on potato dextrose agar. After hyphal tipping a morphologically identical fungus was isolated from 70% of leaves and 88% of petioles, which formed a dense white mycelial mat with moderate aerial mycelium and conidiomata that exuded dark brown conidial masses. The underside of the mycelial mat was yellowish. Conidia were fusoid, ellipsoid, straight to slightly curved, 4-septate with a single basal appendage and 2-5 apical, matching the description of species within the genus (Maharachchikumbura et al. 2014). The average conidia (n=74) length, not including appendages, was 29.9 ± 2.1 µm and the average width, at the widest point, was 7.5 ± 0.7 µm. Aerial hyphae were collected from two isolates, CT58-1 and CT62-2, and DNA was extracted for further molecular characterization. PCR was performed with primers targeting actin (), β-tubulin (), and ITS prior to amplicon sequencing (Carbone and Kohn 1999; Hassan et al. 2018). Sequences were queried against the NCBI whole genome shotgun database, and aligned sequences from 13 species (including , , and ) were collected for each locus. Sequences were aligned, trimmed, and concatenated using Mega11, and IQ-TREE was employed for model selection (Nguyen et al. 2015; Tamura et al. 2021). A maximum-likelihood tree placed the isolates in a high-confidence cluster with , confirming this placement of these isolates within the genus (CT58-1 Accession #: PP715979-89; PP707735). To confirm pathogenicity, CT58-1 was grown on autoclaved strawberry leaves to induce sporulation, and a suspension of 10 spores/ml was made. Five milliliters of this spore suspension was sprayed on six 6-week-old strawberries (cv. Jewel), and water was sprayed on the same number of control plants. Plants were at 100% humidity for two days and then kept in the greenhouse for 3 weeks to observe symptoms. Inoculated plants presented with identical leaf spot and petiole lesions to field samples and no visual symptoms were observed on control plants. New isolations were made from infected petioles, which produced morphologically identical spores to those described above, and ITS/ loci sequencing yielded sequences identical to those of CT58-1. Spore production and plant inoculations were repeated with this new isolate, and identical symptoms were observed. This is the first report of infecting strawberries in New England and given the high disease incidence in the initial infected field and relative lack of disease in a neighboring field, it is likely that this pathogen was introduced on bare root plants. As the plants were sourced from a nursery in Ontario, Canada, it is likely that the pathogen is capable of overwintering in the Northeastern United States.
PubMed: 38803068
DOI: 10.1094/PDIS-04-24-0893-PDN -
Molecules (Basel, Switzerland) Jan 2024American ginseng, a highly valuable crop in North America, is susceptible to various diseases caused by fungal pathogens, including spp., spp., and spp. The...
American ginseng, a highly valuable crop in North America, is susceptible to various diseases caused by fungal pathogens, including spp., spp., and spp. The development of alternative control strategies that use botanicals to control fungal pathogens in American ginseng is desired as it provides multiple benefits. In this study, we isolated and identified three fungal isolates, , , and , from diseased American ginseng plants. Ethanolic and aqueous extracts from the roots and leaves of goldenseal were prepared, and the major alkaloid constituents were assessed via liquid chromatography-mass spectrometry (LC-MS). Next, the antifungal effects of goldenseal extracts were tested against these three fungal pathogens. Goldenseal root ethanolic extracts exhibited the most potent inhibition against fungal growth, while goldenseal root aqueous extracts and leaf ethanolic extracts showed only moderate inhibition. At 2% (/) concentration, goldenseal root ethanolic extracts showed an inhibition rate of 86.0%, 94.9%, and 39.1% against , , and , respectively. The effect of goldenseal root ethanolic extracts on the mycelial morphology of fungal isolates was studied via scanning electron microscopy (SEM). The mycelia of the pathogens treated with the goldenseal root ethanolic extract displayed considerable morphological alterations. This study suggests that goldenseal extracts have the potential to be used as a botanical fungicide to control plant fungal diseases caused by , , or
Topics: Hydrastis; Panax; Plant Roots; Alkaloids; Plant Extracts
PubMed: 38338301
DOI: 10.3390/molecules29030556 -
International Journal of Molecular... Mar 2024The genus consists of obligate parasites that cause ring spot, scab, and leaf blight diseases in higher plant species. We assembled the three complete mitogenomes for...
The genus consists of obligate parasites that cause ring spot, scab, and leaf blight diseases in higher plant species. We assembled the three complete mitogenomes for the guava fruit ring spot pathogen, . The mitogenomes are circular, with sizes of 38,666 bp, 33,846 bp, and 32,593 bp. The comparative analyses with showed that differs greatly from it in the length of the mitogenomes and the number of introns. Moreover, they showed significant differences in the gene content and tRNAs. The two genera showed little difference in gene skewness and codon preference for core protein-coding genes (PCGs). We compared gene sequencing in the mitogenomes of the order and found large-scale gene rearrangement events, such as gene translocations and the duplication of tRNAs. shows a unique evolutionary position in the phylum constructed in phylogenetic analyses. We also found a more concentrated distribution of evolutionary pressures on the PCGs of in the phylum and that they are under little selective pressure compared to other species and are subjected to purifying selection. This study explores the evolutionary dynamics of the mitogenomes of and provides important support for genetic and taxonomic studies.
Topics: Phylogeny; Xylariales; RNA, Transfer; Introns; Genome, Mitochondrial
PubMed: 38542068
DOI: 10.3390/ijms25063093 -
Frontiers in Microbiology 2023Two new caryophyllene-type sesquiterpenes pestalotiopsins U and V ( and ) and three known compounds pestalotiopsin B (), pestaloporinate B (), and pestalotiopsin C ()...
Two new caryophyllene-type sesquiterpenes pestalotiopsins U and V ( and ) and three known compounds pestalotiopsin B (), pestaloporinate B (), and pestalotiopsin C () were isolated by the cultivation of the endophytic fungus on solid rice medium, while four additional new caryophyllene pestalotiopsins W-Z (-) were obtained when 3.5% NaI was added to the fungal culture medium. The structures of the new compounds were determined by HRESIMS and 1D/2D nuclear magnetic resonance data. Compounds - were tested for cytotoxicity against the mouse lymphoma cell line L5178Y, but only displayed significant activity with an IC value of 2.4 μM.
PubMed: 38274753
DOI: 10.3389/fmicb.2023.1248896 -
International Journal of Molecular... Mar 2024Tea grey blight disease is one of the most destructive diseases that infects tea and is caused by the pathogen (Sawada) Steyaert. L-theanine is a unique non-protein...
Tea grey blight disease is one of the most destructive diseases that infects tea and is caused by the pathogen (Sawada) Steyaert. L-theanine is a unique non-protein amino acid of the tea plant. Different concentrations of L-theanine exhibit significant inhibitory effects on the growth and sporulation ability of the pathogen causing tea grey blight disease. To understand the effect mechanism of L-theanine on , transcriptome profiling was performed on the pathogenic mycelium treated with three different concentrations of L-theanine: no L-theanine treatment (TH0), 20 mg/mL theanine treatment (TH2), and 40 mg/mL theanine treatment (TH4). The colony growths were significantly lower in the treatment with L-theanine than those without L-theanine. The strain cultured with a high concentration of L-theanine produced no spores or only a few spores. In total, 2344, 3263, and 1158 differentially expressed genes (DEGs) were detected by RNA-sequencing in the three comparisons, Th2 vs. Th0, Th4 vs. Th0, and Th4 vs. Th2, respectively. All DEGs were categorized into 24 distinct clusters. According to GO analysis, low concentrations of L-theanine primarily affected molecular functions, while high concentrations of L-theanine predominantly affected biological processes including external encapsulating structure organization, cell wall organization or biogenesis, and cellular amino acid metabolic process. Based on KEGG, the DEGs of Th2 vs. Th0 were primarily involved in pentose and glucuronate interconversions, histidine metabolism, and tryptophan metabolism. The DEGs of Th4 vs. Th0 were mainly involved in starch and sucrose metabolism, amino sugar, and nucleotide sugar metabolism. This study indicated that L-theanine has a significant impact on the growth and sporulation of the pathogen of tea grey blight disease and mainly affects amino acid metabolism, carbohydrate metabolism, and cellular structure-related biosynthesis processes of pathogenic fungi. This work provides insights into the direct control effect of L-theanine on pathogenic growth and also reveals the molecular mechanisms of inhibition of L-theanine to .
Topics: Transcriptome; Glutamates; Camellia sinensis; Plant Leaves; Tea; Ascomycota
PubMed: 38542498
DOI: 10.3390/ijms25063493 -
Plant Disease Jan 2024In September 2022, leaf blight symptoms (Fig. 1) were detected on six-year-old kiwi trees (Actinidia chinensis cv. 'Hongyang') in Xuzhou municipality (117.29º E,...
In September 2022, leaf blight symptoms (Fig. 1) were detected on six-year-old kiwi trees (Actinidia chinensis cv. 'Hongyang') in Xuzhou municipality (117.29º E, 34.23º N), Jiangsu Province. Early-stage disease symptoms included light brown necrotic lesions of irregular shape ranging in length from 0.2 to 2.4 cm, which turned into leaf blight after approximately 2 weeks. Those symptoms were similar to those previously reported during a Pestalotiopsis sp. infection on kiwi trees in Turkey (Karakaya 2001). Approximately 20% of the leaves from 300 trees examined in one kiwi orchard, 3000 m2 in size, showed the disease symptoms. Ten leading edges of symptomatic leaves were sterilized with 2% sodium hypochlorite for 1 min, rinsed twice with sterile ddH2O and cultured at 26ºC for 3 days on PDA medium containing 50 µg/ml chloramphenicol. The fungal colonies were collected, and the single spore isolation method was used to obtain four isolates. The obtained isolates showed white aerial mycelia that turned greyish after 2 days of cultivation on PDA medium at 26ºC. ITS (OR054113, OR054153-OR054155), TUB2 (OR060951-OR060953, OR249978), and CMD (OR255947-OR255950) genes were amplified using the ITS1/ITS4, BT2a/BT2b and CMD5/CMD6 primers, respectively (Visagie et al. 2014a). The obtained ITS, TUB2, and CMD sequences shared 99.81%-100%, 96.72%-96.96%, and 90.17%-92.58% homology compared to the ex-type strain P. oxalicum CBS 219.30 (MH855125, KF296462, and KF296367), while the obtained ITS and TUB2 sequences showed 99.62%-99.81%, and 96.46%-96.72% identity compared to the representative strain P. oxalicum DTO 179B9 (KJ775647 and KJ775140) (Visagie et al. 2014b). The sequences obtained also showed high homology compared to P. oxalicum HP7-1 (ITS: 99.81%-100% homology; TUB2: 98.98%-99.38% homology; CMD: 94.71%-95.10% homology) (Li et al. 2022). A molecular phylogenetic tree was constructed using MEGA X with representative Penicillium strains retrieved from GenBank (Fig. 2). Microscope observations revealed the presence of curved septate hyphae. Conidia were colorless, unicellular, and ellipsoidal (5-8 μm in length; > 2000 observations), whereas conidiophores were mainly monoverticillate (approximately 20% of the conidiophores were biverticillate) (50-70 μm in length; 43 observations) and contained cylindrical phialides (13-15 μm in length). These findings are consistent with P. oxalicum morphology (Wu et al. 2022; Zheng et al. 2023). The pathogenicity of the four isolates was screened using healthy non-detached 'Hongyang' kiwi leaves. Fifteen leaves from five different two-month-old trees were used for each isolate, with three repetitions. For inoculation, a 10 mL solution containing 1 × 106 spores/mL was sprayed on the leaves. Sterilized water was used in the control experiment, which was carried out using fifteen leaves from five different two-month-old trees, with three repetitions. Inoculated trees were stored at 26ºC and 60% relative humidity for 2 days. All the infected leaves had necrotic lesions and leaf blight symptoms comparable to those found in the field, but the control leaves had no lesions. The pathogen was recovered, and its identity was confirmed by ITS sequencing and morphology analysis, fulfilling Koch's postulates. P. oxalicum is a common cause of blue mould in postharvest fruits (Tang et al. 2020). P. oxalicum has been recently reported as the causal agent of leaf spot in pineapple (Wu et al. 2022; Zheng et al. 2023), and leaf blight on maize (Han et al. 2023). Although Alternaria sp., Glomerella cingulate, Pestalotiopsis sp., Phomopsis sp., and Phoma sp. were previously isolated from kiwi leaves with blight symptoms (Kim et al. 2017), this is the first report of P. oxalicum causing leaf blight on kiwi trees worldwide. P. oxalicum is a well-known source of mycotoxins, such as secalonic acid (Otero et al. 2020), indicating that its presence in kiwifruit orchards may pose a significant risk to human health. The discovery of this hazardous pathogen in kiwi trees must drive the development of management strategies. Kiwifruit is an important dietary source of vitamins, fiber, folate, and potassium, and China is the major producer of kiwifruit, with more than 1.2 million metric tons harvested in 2021. This report will help to generate a better understanding of the pathogens affecting kiwifruit orchards in China.
PubMed: 38170442
DOI: 10.1094/PDIS-07-23-1341-PDN -
Plants (Basel, Switzerland) Mar 2024Fungal attacks have become a major obstacle in tea plantations. is one of the most devastating fungal pathogens in tea plantations that can severely affect tea yield...
Fungal attacks have become a major obstacle in tea plantations. is one of the most devastating fungal pathogens in tea plantations that can severely affect tea yield and quality. However, the molecular mechanism of resistance genes involved in anthracnose is still largely unknown in tea plants. Here, we found that the laccase gene was involved in the response to fungal infection based on a transcriptome analysis. The full-length CDS of was cloned, and its protein sequence had the closest relationship with the AtLAC15 protein compared to other AtLACs. Tissue-specific expression analysis showed that had higher expression levels in mature leaves and stems than in the other tissues. Subcellular localization showed that the CsLAC37 protein was predominantly localized in the cell membrane. The expression levels of were upregulated at different time points under cold, salt, SA, and ABA treatments. qRT-PCR confirmed that responded to both -like species and infections. Functional validation showed that the hydrogen peroxide (HO) content increased significantly, and POD activity decreased in leaves after antisense oligonucleotide (AsODN) treatment compared to the controls. The results demonstrated that may play an important role in resistance to anthracnose, and the findings provide a theoretical foundation for molecular breeding of tea varieties with resistance to fungal diseases.
PubMed: 38592904
DOI: 10.3390/plants13060884 -
PLoS Biology Jan 2024Chitin deacetylases (CDAs) emerge as a valuable tool to produce chitosans with a nonrandom distribution of N-acetylglucosamine (GlcNAc) and glucosamine (GlcN) units. We...
Chitin deacetylases (CDAs) emerge as a valuable tool to produce chitosans with a nonrandom distribution of N-acetylglucosamine (GlcNAc) and glucosamine (GlcN) units. We hypothesized before that CDAs tend to bind certain sequences within the substrate matching their subsite preferences for either GlcNAc or GlcN units. Thus, they deacetylate or N-acetylate their substrates at nonrandom positions. To understand the molecular basis of these preferences, we analyzed the binding site of a CDA from Pestalotiopsis sp. (PesCDA) using a detailed activity screening of a site-saturation mutagenesis library. In addition, molecular dynamics simulations were conducted to get an in-depth view of crucial interactions along the binding site. Besides elucidating the function of several amino acids, we were able to show that only 3 residues are responsible for the highly specific binding of PesCDA to oligomeric substrates. The preference to bind a GlcNAc unit at subsite -2 and -1 can mainly be attributed to N75 and H199, respectively. Whereas an exchange of N75 at subsite -2 eliminates enzyme activity, H199 can be substituted with tyrosine to increase the GlcN acceptance at subsite -1. This change in substrate preference not only increases enzyme activity on certain substrates and changes composition of oligomeric products but also significantly changes the pattern of acetylation (PA) when N-acetylating polyglucosamine. Consequently, we could clearly show how subsite preferences influence the PA of chitosans produced with CDAs.
Topics: Chitosan; Chitin; Polymers; Amidohydrolases; Acetylation
PubMed: 38236907
DOI: 10.1371/journal.pbio.3002459 -
MycoKeys 2024Chinese yew, Taxuschinensisvar.mairei is an endangered shrub native to south-eastern China and is widely known for its medicinal value. The increased cultivation of...
Chinese yew, Taxuschinensisvar.mairei is an endangered shrub native to south-eastern China and is widely known for its medicinal value. The increased cultivation of Chinese yew has increased the incidence of various fungal diseases. In this study, Pestalotioid fungi associated with needle spot of Chinese yew were isolated from Guangxi Province. Based on morphological examinations and multi-locus (ITS, , ) phylogenies, these isolates were identified to five species, including two new species, and , two potential novel species, sp. 3 and sp. 4, with a known species (), firstly recorded from Chinese yew. These two new species were morphologically and phylogenetically distinct from the extant Pestalotioid species in Chinese yew. Pathogenicity and culture characteristic tests of these five Pestalotioid species were also performed in this study. The pathogenicity test results revealed that sp. 3 can cause diseases in Chinese yew needles. These results have indicated that the diversity of Pestalotioid species associated with Chinese yew was greater than previously determined and provided helpful information for Chinese yew disease diagnosis and management.
PubMed: 38449923
DOI: 10.3897/mycokeys.102.113696