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Molecular Microbiology Aug 2019Fungal 1,8-dihydroxynaphthalene (DHN) melanin plays important roles in UV protection, oxidative stress and pathogenesis. However, knowledge of the regulatory mechanisms...
Fungal 1,8-dihydroxynaphthalene (DHN) melanin plays important roles in UV protection, oxidative stress and pathogenesis. However, knowledge of the regulatory mechanisms of its biosynthesis is limited. Previous studies showed two transcription factors, PfmaF and PfmaH, located in the DHN melanin biosynthetic gene cluster (Pfma) in Pestalotiopsis fici. In this study, deletion of PfmaH resulted in loss of melanin and affected conidia cell wall integrity. Specifically, PfmaH directly regulates the expression of scytalone dehydratase, which catalyzes the transition of scytalone to T HN. However, PfmaF disruption using CRISPR/Cas9 system affected neither DHN melanin distribution nor conidia cell wall integrity in P. fici. Unexpectedly, overexpression of PfmaF leads to heavy pigment accumulation in P. fici hyphae. Transcriptome and qRT-PCR analyses provide insight into the roles of PfmaF and PfmaH in DHN melanin regulation. PfmaH, as a pathway specific regulator, mainly regulates melanin biosynthesis that contributes to cell wall development. Furthermore, PfmaF functions as a broad regulator to stimulate PfmaH expression in melanin production, secondary metabolism as well as fungal development.
Topics: Biosynthetic Pathways; Fungal Proteins; Gene Expression Regulation, Developmental; Gene Expression Regulation, Fungal; Melanins; Naphthols; Spores, Fungal; Transcription Factors; Xylariales
PubMed: 31116900
DOI: 10.1111/mmi.14281 -
Data in Brief Oct 2023Bananas, one of the most widely consumed fruits globally, are highly susceptible to various leaf spot diseases, leading to significant economic losses in banana...
Bananas, one of the most widely consumed fruits globally, are highly susceptible to various leaf spot diseases, leading to significant economic losses in banana production. In this article, we present the Banana Leaf Spot Diseases (BananaLSD) dataset, an extensive collection of images showcasing three prevalent diseases affecting banana leaves: Sigatoka, Cordana, and Pestalotiopsis. The dataset was used to develop the BananaSqueezeNet model [1]. The BananaLSD dataset contains 937 images of banana leaves collected from banana fields, which were then further augmented to generate another 1600 images. The images were acquired using three smartphone cameras in diverse real-world conditions. The dataset has potential for reuse in the development of machine learning models that can help farmers identify symptoms early. It can be useful for researchers working on leaf spot diseases and serve as motivation for further researches.
PubMed: 37823069
DOI: 10.1016/j.dib.2023.109608 -
Microbiological Research 2016The objective of this study was to elucidate the endophytic microbiota in rice sprouts, roots, and stems, and their transmission in the plant development. Prior to DNA...
The objective of this study was to elucidate the endophytic microbiota in rice sprouts, roots, and stems, and their transmission in the plant development. Prior to DNA extraction, roots and stems were treated with 36% formaldehyde and 0.1M NaOH solutions to remove epiphytic bacterial whole 16S rRNA genes. Bacterial and fungal taxa in the sprout, root, and stem samples were analyzed using Illumina-based sequencing of the V3-V4 hyper variable regions of bacterial 16S rRNA genes and the ITS2 regions of fungal rRNA genes, respectively. Results showed that more diverse bacterial OTUs were detected in roots than in stems, while more diverse fungal OTUs were detected in stems than in roots. Compared with the endophytic microbiota in sprouts, the bacterial OTUs increased in roots but decreased in stems, whereas the fungal OTUs in both stems and roots decreased. Sprout-borne bacterial genera Sphingomonas and Pseudomonus, and fungal genera Fusarium, Pestalotiopsis, and Penicillium were detected in stems and roots. The coexistence of these indigenous bacterial and fungal taxa in sprouts, roots, and stems indicated their transmission during the development from sprouts to mature plants. The results from this study should be useful to better understand the plant-microbe interactions and to select suitable microbial taxa for rice production.
Topics: Bacteria; Cluster Analysis; DNA, Bacterial; DNA, Fungal; DNA, Ribosomal; DNA, Ribosomal Spacer; Endophytes; Fungi; Microbiota; Oryza; Phylogeny; Plant Roots; Plant Stems; RNA, Ribosomal, 16S; Seedlings; Sequence Analysis, DNA
PubMed: 27296957
DOI: 10.1016/j.micres.2016.04.009 -
Natural Products and Bioprospecting Jun 2016Three new drimane sesquiterpenoids (1-3) together with the known 2α-hydroxyisodrimeninol (4), and a new isochromone derivative (5), were obtained from the solid...
Three new drimane sesquiterpenoids (1-3) together with the known 2α-hydroxyisodrimeninol (4), and a new isochromone derivative (5), were obtained from the solid cultures of fungal strain Pestalotiopsis sp. M-23, an endophytic fungus isolated from the leaves of Leucosceptrum canum (Labiatae). Their structures were determined by comprehensive 1D and 2D NMR, and MS analyses. The metabolites were evaluated for their antibacterial activities, and compound 3 showed weak inhibitory activity against Bacillus subtilis.
PubMed: 27038619
DOI: 10.1007/s13659-016-0094-6 -
Mycology 2016Mangrove forests play an important role in subtropical and tropical coastal ecosystems. Endophytic fungi are widely distributed in various ecosystems and have great...
Mangrove forests play an important role in subtropical and tropical coastal ecosystems. Endophytic fungi are widely distributed in various ecosystems and have great contribution to global biodiversity. In order to better understand the effects of mangrove species and tissue types on endophytic fungal community, we investigated cultivable endophytic fungi in leaves and twigs of four mangroves , and in Guangxi, China. The four tree species had similar overall colonisation rates of endophytic fungi (24-33%). The colonisation rates of endophytic fungi were higher in twigs (30-58%) than in leaves (6-25%) in the four plant species. A total of 36 endophytic fungal taxa were identified based on morphological characteristics and molecular data, including 35 Ascomycota and 1 Basidiomycota, dominated by and . The diversity of endophytic fungi was higher in twigs than in leaves in the four plant species. Some endophytic fungi showed host and tissue preference. The endophytic fungal community composition was different among four mangrove species and between leaf and twig tissues.
PubMed: 30123630
DOI: 10.1080/21501203.2016.1258439 -
Plant Disease Oct 2022Rhododendron delavayi is an evergreen shrub with large scarlet flowers that make it highly attractive as an ornamental species. The species is native to southwest China...
Rhododendron delavayi is an evergreen shrub with large scarlet flowers that make it highly attractive as an ornamental species. The species is native to southwest China (Cai et al. 2015). From May to July in 2022, symptoms of leaf spot were observed on R. delavayi over a wide portion of the Baili Azalea Forest Area (N 27°10'-27°20', E 105°04'-106°04'), Guizhou Province, China. About 500 plants were surveyed and the incidence of leaf spot on R. delavayi leaves was 20 to 30%, significantly reducing their ornamental and economic value. The affected leaves had irregular, dark brown lesions with a clear blackish brown boundary and black conidiomata in a grayish center. To isolate the pathogen, 15 symptomatic leaves were collected from 10 plants. A few black dots were picked from the lesions with a sterilized needle, plated on water agar and incubated at 25℃ for 24 h to observe spore germination (Choi et al. 1999). Then the germinated spores were transferred onto PDA for further purification and morphological observation. Three single-spore isolates (GUDJ 61, GUDJ 62, GUDJ 63) that produced identical in morphology were obtained. The isolate GUDJ 61 was used for further study. Colonies on PDA grew velvety white on the upper surface and light yellow on the lower surface. Conidia were 5-celled, spindle- to ellipsoid-shaped, straight or slightly curved, 4-septate, and measured 39.0 ± 3.7 × 10.4 ± 0.79 µm (n=50). The morphological features were consistent with the description of Pestalotiopsis scoparia Maharachch., K.D. Hyde & Crous, (Maharachchikumbura et al. 2014). The pathogen was confirmed to be P. scoparia by amplification and sequencing of the internal transcribed spacer region (ITS), the partial β-tubulin (TUB), and the partial translation elongation factor 1-alpha (TEF) genes using primers ITS4/ITS5, T1/Bt-2b, and EF1-728F/EF-2, respectively. Sequences from PCR amplification were deposited in GenBank with accession numbers OP048045 (ITS), OP058111 (TUB) and OP058114 (TEF), respectively. BLAST searches of the sequences revealed 99% (549/552 nt), 99% (711/714 nt), and 82% (130/158 nt) homology with those of P. scoparia CBS 176.25T form GenBank (KM199330, KM199393, and KM199478), respectively. Phylogenetic analysis (MEGA 7.0) using the maximum likelihood method placed the isolate GUDJ 61 in a well-supported cluster with P. scoparia. The pathogen was thus identified as P. scoparia based on the morphological characterization and molecular analyses. The pathogenicity of GUDJ 61was tested through a pot assay. Ten healthy R. delavayi plants were scratched with a sterilized needle (0.45 mm in diameter) on three leaves per plant. Plants were inoculated by spraying a spore suspension (106 spores mL-1) of GUDJ 61 onto leaves until runoff, and the control leaves sprayed with sterile water. The plants were maintained at 25°C and 75% relative humidity in a growth chamber. The pathogenicity test was repeated three times (Fang 2007). After 12 days, the treated leaves developed brown lesions similar to those in the field, while the control had no symptoms. The same fungus was reisolated from the infected leaves and identified based on a morphological characterization and molecular analyses. These results fulfilled Koch's postulates. To our knowledge, this is the first report of leaf spot on R. delavayi caused by P. scoparia in China. The fungal pathogen identification will provide valuable information for prevention and management of leaf spot disease associated with R. delavayi.
PubMed: 36265150
DOI: 10.1094/PDIS-08-22-1896-PDN -
Mycology Aug 2020A survey of the diversity and distribution of microfungi on leaf litter in Songkhla Province (Thailand) yielded two collections of pestalotiopsis-like fungi. Analyses...
A survey of the diversity and distribution of microfungi on leaf litter in Songkhla Province (Thailand) yielded two collections of pestalotiopsis-like fungi. Analyses of a combined ITS, TEF1-α and TUB2 sequence data matrix were applied to infer the phylogenetic position of these new isolates in . The phylogenies indicated that these two isolates were monophyletic and constituted a distinct lineage that perceived a taxonomic novelty in . This clade shared a close phylogenetic affinity with and . The comparison of morphological features with the phylogenetically closely related taxa are given and the new species is introduced as sp. nov. with comprehensive descriptions and illustrations herein.
PubMed: 33329926
DOI: 10.1080/21501203.2020.1801873 -
Interactions between abundant fungal species influence the fungal community assemblage on limestone.PloS One 2017The assembly of fungal communities on stone materials is mainly influenced by the differential bioreceptivity of such materials and environmental conditions. However,...
The assembly of fungal communities on stone materials is mainly influenced by the differential bioreceptivity of such materials and environmental conditions. However, little is known about the role of fungal interactions in the colonization and establishment of fungal species. We analyzed the effects of intra- and interspecific interactions between 11 species of fungi in oligotrophic and copiotrophic media and on limestone coupons. In a previous study, these species were the most frequently isolated in the epilithic biofilms of limestone walls exposed to a subtropical climate. In the culture media, we found a greater frequency of intra- and interspecific inhibitory effects in the oligotrophic medium than in the copiotrophic medium. On the limestone coupons, all fungi were able to establish; however, the colonization success rate varied significantly. Cladosporium cladosporioides had a less extensive colonization in isolation (control) than in dual interactions (coexistence) with other species. Phoma eupyrena exhibited the highest colonization success rate and competitive dominance among all tested species. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses revealed that Pestalotiopsis maculans and Paraconiothyrium sp. produced calcium oxalate crystals during their growth on coupon surfaces, both in isolation and in dual interactions. Our results demonstrate that interactions between abundant fungal species influence the fungal colonization on substrates, the biomineralization and the fungal community assemblage growing in limestone biofilms.
Topics: Calcium Carbonate; Culture Media; Fungi; Microscopy, Electron, Scanning; Species Specificity; X-Ray Diffraction
PubMed: 29211748
DOI: 10.1371/journal.pone.0188443 -
Current Medical Mycology Jun 2020Pestalotioid fungi are ubiquitous environmental molds that have received considerable attention in recent times not only because of their role as a plant pathogen but...
BACKGROUND AND PURPOSE
Pestalotioid fungi are ubiquitous environmental molds that have received considerable attention in recent times not only because of their role as a plant pathogen but also owing to their high frequency of retrieval from human diseases. Regarding this, the present study was conducted to investigate onychomycosis caused by pestalotioid fungi, commonly considered important phytopathogens causing grey blight disease in .
MATERIALS AND METHODS
A total of 122 agriculture workers were enrolled from Assam, India. Direct microscopic examination was carried out using 40% KOH to determine the presence of any fungal element. Further processing of the specimens for the isolation of fungi was performed using the standard protocol. In addition, the keratinolytic potential of the isolates was evaluated by means of the in vitro hair perforation test.
RESULTS
Out of 103 culture-positive samples, non-dermatophyte and dermatophyte molds constituted 82.52% (n=85) and 6.79% (n=7) of the samples, followed by yeasts (n=1, 0.9%) and sterile hyphae (n=10, 9.7%). With regard to the isolated non-dermatophyte molds (82.69%), 4 cases belonged to pestalotioid fungi, such as (n=1), (n=1), and (n=2). The keratinolytic activity of Pestalotiopsis species showed perforation by disrupting the hair cortex; furthermore, macroconidia were found to be present inside the human hair.
CONCLUSION
A high rate of NDM isolation may be attributed to constant exposure to adverse environmental and occupational hazards. This study highlighted the importance of "pestalotioid fungi" as the rare etiologic agent of onychomycosis. Another remarkable finding was the keratinolytic potential of species, which is unique in this study.
PubMed: 33628978
DOI: 10.18502/CMM.6.2.2839 -
Frontiers in Microbiology 2021Eight rhizospheric bacteria were isolated from the organic paddy fields of Sikkim, India, and identified as KSB, SRD, YMA7, SRB, sp. ARA, COW3, PSB2, and PSB1....
Isolation, Characterization, and Evaluation of Native Rhizobacterial Consortia Developed From the Rhizosphere of Rice Grown in Organic State Sikkim, India, and Their Effect on Plant Growth.
Eight rhizospheric bacteria were isolated from the organic paddy fields of Sikkim, India, and identified as KSB, SRD, YMA7, SRB, sp. ARA, COW3, PSB2, and PSB1. They showed plant growth-promoting attributes in rice and have bio-control potential against phytopathogen of large cardamom (). SRD showed production of indole acetic acid and ammonia and solubilization of phosphate and potassium and also possessed nitrogen fixation potential. It showed antagonistic activity against two other plant pathogens of large cardamom, viz., and sp., under conditions. The liquid bacterial consortium was prepared using the bacterial strains SRB, PSB1, and COW3 (Consortia-1); PSB2, SRD, and COW3 (Consortia-2); and COW3, KSB, and YMA7 (Consortia-3) to increase the growth and yield of rice plants under organic farming conditions. Greenhouse and field studies showed that the Consortia-3 had the highest plant growth-promoting activity. Consortia-3 demonstrated better agronomic performance in terms of root length (9.5 cm),number of leaflets per plant (5.3), grains per panicle (110.6), test grain weight (27.4 g), dry root weight per plant (0.73 g), and total dry biomass per plant (8.26 g).
PubMed: 34552571
DOI: 10.3389/fmicb.2021.713660