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Plant Disease Feb 2023Liquidambar formosana Hance, a deciduous tree, is widely cultivated in China for its ornamental and afforestation value (Yin et al. 2021). In July 2019, leaf spot...
Liquidambar formosana Hance, a deciduous tree, is widely cultivated in China for its ornamental and afforestation value (Yin et al. 2021). In July 2019, leaf spot symptoms were observed with 20 to 30% disease incidence in Li shan forest farm (27°19'27.2″N, 115°32'51.08″E) in Ji'an city, Jiangxi province, China. Initial disease symptoms were small spots, which enlarged and circular to irregular, gray in the center, and dark brown to black circular on the lesion margin. Leaf pieces (5 × 5 mm) from the lesion borders were surfaced and sterilized in 70% ethanol for 30 s, followed by 2% NaOCl for 1 min, and then rinsed three times with sterile water (Si et al. 2022). Tissues were placed on potato dextrose agar (PDA) and incubated at 25°C. Pure cultures were obtained by monosporic isolation, and the representative isolates, FX-2, FX-5, and FX-9 were used for morphological studies and phylogenetic analyses. The colonies of three isolates on PDA grew fast, covering the entire plate with white cottony mycelia with black acervuli after 8 to 10 days. Conidia were 5-celled, clavate to fusiform, smooth, 19.6-24.2 × 6.2-8.5 μm (n = 100). The 3 median cells were dark brown to olivaceous, central cell was darker than other 2 cells, and the basal and apical cells were hyaline. All conidia developed one basal appendage (3.5-8.2 μm long; n = 100), and 2-3 apical appendages (18-31 μm long; n = 100), filiform. Morphological features were similar to Neopestalotiopsis sp. (Maharachchikumbura et al. 2014). The internal transcribed spacer (ITS) regions, β-tubulin 2 (TUB2) and translation elongation factor 1-alpha (TEF1-α) were amplified from genomic DNA for the three isolates using primers ITS1/ITS4, T1/Bt-2b, EF1-728F/EF-2 (Maharachchikumbura et al. 2014), respectively. All sequences were deposited into GenBank (ITS, ON622512- ON622514; TUB2, ON676532 - ON676534; TEF1-α, ON676529 - ON676531). A maximum likelihood and Bayesian posterior probability analyses using IQtree v. 1.6.8 and Mr. Bayes v. 3.2.6 with the concatenated sequences placed FX-2, FX-5, and FX-9 in the clade of N. clavispora. Based on the multi-locus phylogeny and morphology, three isolates were identified as N. clavispora. To confirm pathogenicity, 10 healthy 2-year-old seedlings, and 5 leaves per seedling were wounded with a sterile needle (Φ=0.5 mm) and inoculated with 200 μL conidial suspension per leaf(106 conidia/mL). Ten control plants were inoculated with ddH2O. All the inoculated leaves were covered with plastic bags and kept in a greenhouse at 26 ± 2 °C and RH 70%. All the inoculated leaves showed similar symptoms to those observed in the field, whereas control leaves were asymptomatic for 8 days. N. clavispora was reisolated from the lesions, whereas no fungus was isolated from control leaves. N. clavispora can cuase leaf diseases in a variety of hosts, including × Taxodiomeria peizhongii (Zhang et al. 2022), Macadamia integrifolia (Qiu et al. 2020), Dendrobium officinale (Cao et al. 2022). N. cocoes, N. chrysea, Pestalotiopsis neglecta and P. neolitseae were also reported to infect L. formosana (Fan et al. 2021). However, this is the first report of N. clavispora infecting L. formosana in China. This work provided crucial information for epidemiologic studies and appropriate control strategies for this newly emerging disease.
PubMed: 36724035
DOI: 10.1094/PDIS-12-22-2825-PDN -
Journal of Fungi (Basel, Switzerland) Dec 2021Melanins are the common fungal pigment, which contribute to stress resistance and pathogenesis. However, few studies have explored the regulation mechanism of its...
Melanins are the common fungal pigment, which contribute to stress resistance and pathogenesis. However, few studies have explored the regulation mechanism of its synthesis in filamentous fungi. In this study, we identified two transcription factors, Pmr1 and Pmr2, in the filamentous fungus . Computational and phylogenetic analyses revealed that Pmr1 and Pmr2 were located in the gene cluster for melanin biosynthesis. The targeted deletion mutant strain displayed defects in biosynthesis of conidia pigment and morphological integrity. The deletion of resulted in reduced conidia pigment, but the mycelial morphology had little change. Moreover, produced decreased conidia. RT-qPCR data revealed that expression levels of genes in the melanin biosynthesis gene cluster were downregulated from the loss of Pmr1 and Pmr2. Interestingly, the yield of secondary metabolites in the mutant strains and increased, comparing with the wild type, and additionally, Pmr1 played a larger regulatory role in secondary metabolism. Taken together, our results revealed the crucial roles of the transcription factors Pmr1 and Pmr2 in melanin synthesis, asexual development and secondary metabolism in the filamentous fungus .
PubMed: 35049978
DOI: 10.3390/jof8010038 -
Journal of Basic Microbiology Nov 2022The present study focuses on antioxidant, antibacterial, phytochemical potential, and cytotoxicity of secondary metabolites from Colletotrichum gloeosporioides, Fusarium...
The present study focuses on antioxidant, antibacterial, phytochemical potential, and cytotoxicity of secondary metabolites from Colletotrichum gloeosporioides, Fusarium proliferatum, Alternaria arborescens, and Pestalotiopsis vismiae. The scavenging effect of fungal metabolites was determined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH), H O , O -, and reducing power assays. Among the four fungi, A. arborescens have higher antioxidant activity of DPPH (81.12%), H O (74.83%), superoxide (75.74%), and reducing power (0.141) with standard ascorbic acid. Fungal metabolites were found to be significantly effective against all tested pathogens. A. arborescens showed significant amounts of phenolic (138.78 ± 3.70 mg/g of gallic acid equivalent), flavonoid (74.16 ± 3.58 mg/g of quercetin equivalent), as well as cytotoxicity effects in a cancer cell line (A549) with inhibitory concentration (IC = 35 µg/ml at 24 and 48 h). The live and dead cells were analyzed by acridine orange/ethidium bromide staining methods. In addition, A. arborescens metabolites were characterized through gas chromatography-mass spectrometry analysis. The major compounds were found to be phenol, 4-(1,1,3,3-tetramethylbutyl)-, acetamide, N-(3-methylphenyl)-, dibutyl phthalate, and benzo[qr]naphtho[2,1,8,7-fghi] pentacene. The compounds were reported in A. arborescensis up to our knowledge this is the first report. Based on this study, all fungal strains have a significant bioactive capacity with A. arborescens strain exhibiting greater biological properties. Further purification and characterization of A. arborescens bioactive component could lead to an intriguing reservoir of novel pharmacological agents in the future.
Topics: Antioxidants; Phytochemicals; Anti-Bacterial Agents; Flavonoids; Phenols; Plant Extracts
PubMed: 35680569
DOI: 10.1002/jobm.202100680 -
Fungal Biology May 2015Pestalotiopsis-like fungi are an important plant pathogenic genus causing postharvest fruit rot and trunk diseases in grapevine in many countries. Pestalotiopsis-like...
Pestalotiopsis-like fungi are an important plant pathogenic genus causing postharvest fruit rot and trunk diseases in grapevine in many countries. Pestalotiopsis-like fungi diseases were studied in vineyards in nine provinces across China. Multi-gene (ITS, β-tubulin and tef1) analysis coupled with morphology showed that a Neopestalotiopsis sp. and Pestalotiopsis trachicarpicola are associated in causing grapevine fruit rot and trunk diseases in China. Pestalotiopsis trachicarpicola is reported as the causative agent of grapevine diseases in the world for the first time. Neopestalotiopsis sp. caused significantly longer lesions than the other taxon present. This study represents the first attempt to identify and characterize the Pestalotiopsis-like fungi causing grapevine diseases in China using both morphological and molecular approaches.
Topics: China; Fungal Proteins; Molecular Sequence Data; Phylogeny; Plant Diseases; Tubulin; Vitis; Xylariales
PubMed: 25937063
DOI: 10.1016/j.funbio.2014.11.001 -
Scientific Reports Nov 2021Pestalotiopsis and related genera, including Neopestalotiopsis and Pseudopestalotiopsis have damaged many plants for many decades; however, there is little available...
Pestalotiopsis and related genera, including Neopestalotiopsis and Pseudopestalotiopsis have damaged many plants for many decades; however, there is little available information about the fungi on tropical fruit in Thailand. This study isolated and characterized pestalotioid fungi on tropical fruit, investigated host specificity, and screened whether plant extracts could control the fungi. In total, 53 diseased fruit samples were sampled from eight types of fruit trees (jackfruit, rose apple, mangosteen, plum, snake fruit, rambutan, strawberry, and avocado). Based on morphological characteristics, 44 isolates were classified as belonging to pestalotioid taxa. Of these isolates, seven with distinct characteristics were selected for identification using molecular analysis, and six isolates were identified as Neopestalotiopsis and one as Pseudopestalotiopsis. In the cross-inoculation experiment, the isolates exhibited nonhost specificity and could infect at least two host plants. The isolates were used to screen for a potential biocontrol resource using six crude plant extracts (clove, ginger, lemongrass, mangosteen, roselle, and turmeric). All crude extracts except mangosteen could inhibit the growth of Neopestalotiopsis and Pseudopestalotiopsis. Application of crude plant extracts could be a potential treatment to control these diseases on tropical fruit.
Topics: Ascomycota; Fruit; Likelihood Functions; Phylogeny; Plant Diseases; Plant Extracts; Plant Leaves; Sequence Analysis, DNA; Species Specificity; Thailand
PubMed: 34799650
DOI: 10.1038/s41598-021-02113-5 -
Frontiers in Microbiology 2022Post-harvest rot causes enormous economic loss to the global kiwifruit industry. Currently, there are no effective fungicides to combat the disease. It is unclear...
Post-harvest rot causes enormous economic loss to the global kiwifruit industry. Currently, there are no effective fungicides to combat the disease. It is unclear whether silver nanoparticles (AgNPs) are effective in controlling post-harvest rot and, if so, what the underlying antifungal mechanism is. Our results indicated that 75 ppm AgNPs effectively inhibited the mycelial growth and spore germination of four kiwifruit rot pathogens: , , , and . Additionally, AgNPs increased the permeability of mycelium's cell membrane, indicating the leakage of intracellular substance. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that AgNPs induced pathogen hypha shrinkage and distortion, as well as vacuolation in hypha cells, implying that AgNPs caused cellular and organelle structural degradation. The transcriptome sequencing of mycelium treated with AgNPs (24 h / 48 h) was performed on the Illumina Hiseq 4000 sequencing (RNA-Seq) platform. For the time points of 24 h and 48 h, AgNPs treatment resulted in 1,178 and 1,461 differentially expressed genes (DEGs) of , 517 and 91 DEGs of , 1,287 and 65 DEGs of , 239 and 55 DEGs of , respectively. The DEGs were found to be involved in "catalytic activity," "small molecule binding," "metal ion binding," "transporter activity," "cellular component organization," "protein metabolic process," "carbohydrate metabolic process," and "establishment of localization." Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis also revealed that "carbohydrate metabolism," "amino acid metabolism," "energy metabolism," and "xenobiotics biodegradation and metabolism" of "metabolism processes" were the most highly enriched pathways for these DEGs in four pathogens, with "cellular processes" being particularly enriched for Furthermore, quantitative polymerase chain reactions (qPCRs) were used to validate the RNA-seq results. It was also confirmed that AgNPs could significantly reduce the symptoms of kiwifruit rot without leaving any Ag residue on the peel and flesh of kiwifruit. Our findings contributed to a better understanding of the antifungal effect and molecular mechanisms of AgNPs against pathogens causing kiwifruit post-harvest rot, as well as a new perspective on the application of this novel antifungal alternative to fruit disease control.
PubMed: 36118196
DOI: 10.3389/fmicb.2022.988633 -
MycoKeys 2024, commonly referred to as pestalotiopsis-like fungi, exhibit a broad distribution and are frequently found as endophytes, saprobes and pathogens across various plant...
, commonly referred to as pestalotiopsis-like fungi, exhibit a broad distribution and are frequently found as endophytes, saprobes and pathogens across various plant hosts. The taxa within pestalotiopsis-like fungi are classified into three genera viz. , and , based on the conidial colour of their median cells and multi-locus molecular phylogenies. In the course of a biodiversity investigation focusing on pestalotiopsis-like fungi, a total of 12 fungal strains were identified. These strains were found to be associated with stromata of , and in various regions of Taiwan from 2018 to 2021. These strains were evaluated morphologically and multi-locus phylogenetic analyses of the ITS (internal transcribed spacer), (translation elongation factor 1-α) and (beta-tubulin) gene regions were conducted for genotyping. The results revealed seven well-classified taxa and one tentative clade in and . One novel species, and four new records, , , and , were reported for the first time in Taiwan. In addition, and an unclassified strain of were identified, based on similarities of phylogeny and morphology. However, the data obtained in the present study suggest that the currently recommended loci for species delimitation of pestalotiopsis-like fungi do not deliver reliable or adequate resolution of tree topologies. The mycelial growth rates of selected strains from these taxa had an optimum temperature of 25 °C, but growth ceased at 5 °C and 35 °C, while all the strains grew faster under alkaline than acidic or neutral pH conditions. This study provides the first assessment of pestalotiopsis-like fungi, associated with entomopathogenic taxa.
PubMed: 38333551
DOI: 10.3897/mycokeys.101.113090 -
Microorganisms Nov 2022In the present work, research tasks were carried out in the search for fungi with potential biocontrol possibilities in relation to the ash dieback pathogen, . In the...
In the present work, research tasks were carried out in the search for fungi with potential biocontrol possibilities in relation to the ash dieback pathogen, . In the years 2012-2021, dead petioles of and were collected, on which morphological structures of showed unusual symptoms of dying (apothecia) and signs of colonization by other fungi (pseudosclerotial plates). Based on morphological and molecular phylogenetic data, 18 fungal taxa were identified. Thirteen of them belong to Ascomycota: , , sp., sp., , sp., sp., , , , , , sp., and five other taxa are represented by Basidiomycota: sp., , sp., sp. and sp. In 108 dual cultures in vitro, three different types of interactions were distinguished: (i) physical colony contact (5.6%), (ii) presence of an inhibition zone between the colonies (0.9%), and (iii) copartner overgrowth of colonies and partial or complete replacement of the pathogen (93.5%). In the dual cultures, various morphological deformations of hyphae were observed: the development of apical or intercalary cytoplasmic extrusions, development of internal hyphae of the test fungi in pathogens' hyphae, the deformation and disruption of significant sections of hyphae via lysis and mycoparasitism, complete desolation of cells and breakdown of hyphae into short fragments, and disappearing of pigment in the affected hyphae of . The inoculation tests performed in vivo or in glass Petrie dishes showed that all the identified taxa were able to lead to pathological changes in apothecia, and the mycelium of some of them completely covered pseudosclerotial plates of . It was emphasized in the discussion that such activity of these fungi in forest stands may contribute to the reduction in the inoculum reservoir.
PubMed: 36422320
DOI: 10.3390/microorganisms10112250 -
Plant Disease Nov 2022Garcinia mangostana L. is a famous tropical fruit in Asia. In April 2021, a leaf disease on G. mangostana cv. Huazhu was observed in Zhanjiang (21.17° N, 110.18° E),...
Garcinia mangostana L. is a famous tropical fruit in Asia. In April 2021, a leaf disease on G. mangostana cv. Huazhu was observed in Zhanjiang (21.17° N, 110.18° E), Guangdong province, China. Symptoms was on new leaves of 2 year old plants. The spots were circular to irregular, gray in the center, and brown on the lesion margin. The disease incidence was estimated 25% (n = 500 investigated plants from about 50-ha). Twenty diseased leaves were collected from the orchard. The margin of the diseased tissues was cut into 2 mm × 2 mm pieces; surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, respectively; and rinsed thrice with sterile water. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. Twenty-eight isolates were obtained (isolation frequency = 28/4×20 = 35%). Single-spore isolation method was used to recover pure cultures for three isolates (GMN-1, GMN-2, and GMN-3) (Liu et al. 2021). The colonies were initially white with cottony aerial mycelium at 7 days on PDA. Then, they developed black acervular conidiomata at 10 days. Conidia were clavate to fusiform, four-septate, straight or slightly curved, and measured 16.5 to 21.4 µm long (average 19.5 µm; n = 40) × 4.5 to 6.5 µm wide (average 5.2 µm; n = 40). The three median cells were versicolored, whereas the basal and apical cells were hyaline. Conidia had a single basal appendage (4.5 to 5.5 µm long; n = 40) and three apical appendages (19.2 to 24.5 µm long; n = 40). The morphological characteristics of the isolates are comparable with those of the genus Neopestalotiopsis (Sajeewa et al. 2012). Molecular identification was performed using the colony polymerase chain reaction method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012). Sequences were generated from the isolates using primers for the rDNA ITS (ITS1/ITS4), TEF1-α (EF1-728F/EF1-986R), and β-tubulin (T1/βt2b) loci (Sajeewa et al. 2012). The sequences of the isolates were submitted to GenBank (ITS, MZ026535-MZ026537; TEF, MZ032203-MZ032205; β-tubulin, MZ032206-MZ032208). The sequences of the isolates were 100% identical to the type strain MFLUCC12-0281 (accession nos. JX398979, JX399014, and JX399045) through BLAST analysis. The isolates clustered with N. clavispora (MFLUCC12-0280 and MFLUCC12-0281). The pathogenicity was tested in vivo. Individual plants (cv. Huazhu) were grown (n = 2, 1-1.5 year old) in a greenhouse at 24 ℃-30 ℃ with 80% relative humidity. Wounded leaflets were inoculated with 5-mm-diameter mycelial plugs or agar plugs (as control). Besides, sterile cotton balls were immersed in the spore suspension (1 × 105 per mL) and sterile distilled water (control) for about 15 s before they were fixed on the leaves for 3 days. One plant employed for each isolate with nine leaves. The test was performed thrice. Disease symptoms were found on the leaflets after 10 days, whereas the controls remained healthy. The pathogen was re-isolated from infected leaves and phenotypically identical to the original isolates to fulfill Koch's postulates. Neopestalotiopsis clavispora and Pestalotiopsis clavispora are synonyms. The fungus appeared to have a wide host range and distribution including in Thailand, Malaysia, North Queensland, and Australia (Sajeewa et al. 2012;Shahriar et al. 2022). Thus, this is the first report of N. clavispora causing leaf spot on G. mangostana in China. This finding will help improve management strategies against the leaf spots on G. mangostana in China.
PubMed: 36350731
DOI: 10.1094/PDIS-05-22-1120-PDN -
Journal of Fungi (Basel, Switzerland) Dec 2023In Colombia, plantings with the oil palm hybrid between × , known as O × G hybrid, have increased due to its tolerance to bud rot. Despite this, different degrees of...
In Colombia, plantings with the oil palm hybrid between × , known as O × G hybrid, have increased due to its tolerance to bud rot. Despite this, different degrees of foliar necrosis, chlorosis, and leaf blight have been reported in some cultivars; therefore, this work aimed to diagnose this problem. We visited plantation plots with palms exhibiting the mentioned symptoms and collected 21 samples of affected tissues in different disease states. The affected tissues were examined and seeded in a culture medium. Pathogenicity tests were performed and the isolates were characterized by culture and morphological and molecular features. , , , and 25 -like fungi were isolated from the foliar lesions. In the pathogenicity tests, the symptoms observed in the field were reproduced with MFTU01-1, MFTU12, and MFTU21 isolates, which were identified at the species level through a sequence analysis of three genes (, , and ) as with an identical level of 99% based on the results of BLAST and phylogenetic tree analyses. The remaining 22 -like non-pathogenic isolates were identified as species of and . The direct association of with the disease was confirmed via molecular detection in affected tissues in 15 of 21 samples collected for this evaluation. This is the first report of as the causal agent of foliar lesions in O × G hybrid oil palm in Colombia.
PubMed: 38248934
DOI: 10.3390/jof10010024