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Pathogens (Basel, Switzerland) May 2022causes crown rot in wheat. This study aimed to assess the effects of the bacterial strain QTH8 isolated from rhizosphere soil against . Bacterial strain QTH8 was...
causes crown rot in wheat. This study aimed to assess the effects of the bacterial strain QTH8 isolated from rhizosphere soil against . Bacterial strain QTH8 was identified as in accordance with the phenotypic traits and the phylogenetic analysis of 16S rDNA and gene sequence. Culture filtrates of bacterial strain QTH8 inhibited the mycelial growth of and resulted in mycelial malformation such as tumor formation, protoplast condensation, and mycelial fracture. In addition, bacterial strain QTH8 also inhibited the mycelial growth of , sp., , , , , , and . The active compounds produced by bacterial strain QTH8 were resistant to pH, ultraviolet irradiation, and low temperature, and were relatively sensitive to high temperature. After 4 h exposure, culture filtrates of bacterial strain QTH8-when applied at 5%, 10%, 15%, 20%, 25%, and 30%-significantly reduced conidial germination of . The coleoptile infection assay proved that bacterial strain QTH8 reduced the disease index of wheat crown rot. In vivo application of QTH8 to wheat seedlings decreased the disease index of wheat crown rot and increased root length, plant height, and fresh weight. Iturin, surfactin, and fengycin were detected in the culture extract of bacterial strain QTH8 by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Bacterial strain QTH8 was identified for the presence of the , , , , , , and genes using the specific polymerase chain reaction primers. QTH8 has a vital potential for the sustainable biocontrol of wheat crown rot.
PubMed: 35631116
DOI: 10.3390/pathogens11050595 -
Morphological and phylogenetic analyses reveal two new species of Sporocadaceae from Hainan, China.MycoKeys 2022Species of Sporocadaceae have often been reported as plant pathogens, endophytes or saprophytes and are commonly isolated from a wide range of plant hosts. The isolated...
Species of Sporocadaceae have often been reported as plant pathogens, endophytes or saprophytes and are commonly isolated from a wide range of plant hosts. The isolated fungi were studied through a complete examination, based on multilocus phylogenies from combined datasets of ITS//, in conjunction with morphological characteristics. Nine strains were isolated from , and in China which represented four species, , , , and . was a new country record for China and first host record from was first report from in China.
PubMed: 35585932
DOI: 10.3897/mycokeys.88.82229 -
Frontiers in Microbiology 2022In the tobacco phyllosphere, some of the microbes may have detrimental effects on plant health, while many may be neutral or even beneficial. Some cannot be cultivated,...
In the tobacco phyllosphere, some of the microbes may have detrimental effects on plant health, while many may be neutral or even beneficial. Some cannot be cultivated, so culture-independent methods are needed to explore microbial diversity. In this study, both metagenetic analysis and traditional culture-dependent methods were used on asymptomatic healthy leaves and symptomatic diseased leaves of tobacco plants. In the culture-independent analysis, asymptomatic leaves had higher microbial diversity and richness than symptomatic leaves. Both asymptomatic and symptomatic leaves contained several potentially pathogenic bacterial and fungal genera. The putative bacterial pathogens, such as species of , , or , and putative fungal pathogens, such as species of , , , , , and , had a higher relative abundance in symptomatic leaves than asymptomatic leaves. FUNGuild analysis indicated that the foliar fungal community also included endophytes, saprotrophs, epiphytes, parasites, and endosymbionts. PICRUSt analysis showed that the dominant functions of the bacterial community in a symptomatic leaf were cellular processes and environmental information processing. In the other five foliar samples, the dominant functions of the bacterial community were genetic information processing, metabolism, and organismal systems. In the traditional culture-dependent method, 47 fungal strains were isolated from 60 symptomatic tobacco leaf fragments bearing leaf spots. Among them, 21 strains of (29%), (14%), (14%), (10%), (10%), (10%), (5%), (5%), and (5%) all fulfilled Koch's postulates and were found to cause disease on detached tobacco leaves in artificial inoculation tests. Symptoms on detached leaves caused by three strains of in artificial inoculation tests were similar to the original disease symptoms in the tobacco field. This study showed that the combined application of culture-dependent and independent methods could give comprehensive insights into microbial composition that each method alone did not reveal.
PubMed: 35572673
DOI: 10.3389/fmicb.2022.843389 -
Scientific Reports May 2022Taxillus chinensis (DC.) Danser is an extensively used medicinal shrub in the traditional as well as modern systems of medicines. It is a perennial hemiparasitic plant,...
Taxillus chinensis (DC.) Danser is an extensively used medicinal shrub in the traditional as well as modern systems of medicines. It is a perennial hemiparasitic plant, which is difficult to propagate artificially because of its low parasitic rate. Successful parasitism of parasitic plants is to fuse their tissues and connect their vasculature to the host vasculature building a physiological bridge, which can efficiently withdraw water, sugars and nutrients from their host plants. It is reported that endophytic fungi play an important role in cell wall degradation and fusion, which is the key forming process of the physiological bridge. Therefore, in this study, the endophytic fungi from T. chinensis of different hosts were isolated, and then the organisms that could degrade the main components of the cell walls were screened out using a medium consisting of guaihuol and cellulose degradation capacity. The results showed that five strains were screened out from 72 endophytic fungi of T. chinensis which with high enzyme activities for lignocellulosic degradation. The laccase and cellulase activities of five strains reached their peaks at day 7, and the highest enzyme activities of these two enzymes were found in strain P6, which was 117.66 and 1.66 U/mL, respectively. Manganese peroxidase of strain 4 and lignin peroxidase of strain N6 also reached their peaks at day 7 and were the highest among the 5 strains, with enzyme activities of 11.61 and 6.64 U/mL, respectively. Strains 4, 15, 31, N6 and P6 were identified as Colletotrichum sp., Nigerrospora sphaerica, Exserohilum sp., Diaporthe phaseolorum and Pestalotiopsis sp., respectively, according to their morphological and molecular biology properties. The endophytic fungi may secrete efficient cell wall degradation enzymes, which promote the dissolution and relaxation of the cell wall between T. chinensis and host, thus contributing to the parasitism of T. chinensis.
Topics: Colletotrichum; Endophytes; Fungi; Laccase; Loranthaceae; Symbiosis
PubMed: 35546173
DOI: 10.1038/s41598-022-11940-z -
International Journal of Molecular... Mar 2022The strategies of genetic dereplication and manipulation of epigenetic regulators to activate the cryptic gene clusters are effective to discover natural products with...
The strategies of genetic dereplication and manipulation of epigenetic regulators to activate the cryptic gene clusters are effective to discover natural products with novel structure in filamentous fungi. In this study, a combination of genetic dereplication (deletion of pesthetic acid biosynthetic gene, ) and manipulation of epigenetic regulators (deletion of histone methyltransferase gene and histone deacetylase gene ) was developed in plant endophytic fungus . The deletion of with and/or led to isolation of 1 novel compound, pestaloficiol X (), as well as another 11 known compounds with obvious yield changes. The proposed biosynthesis pathway of pestaloficiol X was speculated using comparative analysis of homologous biosynthetic gene clusters. Moreover, phenotypic effects on the conidial development and response to oxidative stressors in the mutants were explored. Our results revealed that the new strain with deletion of or in Δ background host can neutralise the hyperformation of conidia in the mutant, and that the Δ Δ mutant was generally not sensitive to oxidative stressors as much as the Δ Δ mutant in comparison with the single mutant Δ or the parental strains. This combinatorial approach can be applied to discover new natural products in filamentous fungi.
Topics: Biological Products; Epigenesis, Genetic; Epigenomics; Fungi; Plants
PubMed: 35409046
DOI: 10.3390/ijms23073686 -
Plant Disease Apr 2022× Z.J. Ye, J.J. Zhang & S.H. Pan is a hybrid of and . It can adapt to various site conditions and has a good saline-alkali tolerance, which is a unique tree species...
× Z.J. Ye, J.J. Zhang & S.H. Pan is a hybrid of and . It can adapt to various site conditions and has a good saline-alkali tolerance, which is a unique tree species in eastern China. In August 2020, a red foliage blight with an incidence of 70% (105/150 plants) was found on the leaves of × in a nursery, Shanghai, China (121°21'12"E, 31°41'56"N). It developed from apical leaves of branches downwards. The infected leaves became reddish brown and withered. Fresh specimens were collected from 3 infected trees. Small samples (3-4 mm) from lesion margins were sterilized, plated on potato dextrose agar (PDA) and incubated at 25°C. Nine isolates of the same fungus were obtained. Three representative isolates (DFS1-3, DFS1-8, and DFS1-9) were used for morphological and molecular studies and deposited in the China's Forestry Culture Collection Center (cfcc57401 to cfcc57403). The colonies of three isolates on PDA grew fast, covering the entire plate with white cottony mycelia in 7 days. Acervuli of DFS1-3 were 618-996 × 586-945 µm (n = 50). Conidiogenous cells were 4.4-9.8 µm (n = 50) long. Conidia were 5-celled, clavate to fusiform, smooth, 19-24 × 6.4-8.8 µm (n = 50). 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 (3.4-8 µm long; n = 50), and 2-3 apical appendages (15-30 µm long; n = 50), filiform. The morphological characters of DFS1-8 and DFS1-9 were almost identical to DFS1-3. Based on morphological studies, the isolates were sp.. The DNA of 3 isolates was extracted. The internal transcribed spacer region (ITS), β-tubulin 2 () and translation elongation factor 1-alpha () loci were amplified using the primer pairs ITS1/ITS4, T1/Bt-2b, EF1-728F/EF-2. BLAST result showed that ITS of the three isolates were identical to sp. at a high level (greater than 99%), and , were highly similar with sp. (greater than 99%). The sequences were deposited in GenBank [Accession Nos. OM188301 and OM222696 to OM222697 for DFS1-3; OM188303 and OM222698 to OM222699 for DFS1-8; OM188302 and OM222700 to OM222701 for DFS1-9]. 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 (ITS, , ) clustered 3 isolates together with including type isolate (MFLUCC 12-0281). Based on the morphology and phylogeny, the fungus was . To confirm pathogenicity, 9 healthy 2-yr-old seedlings, and 10 leaves per seedling were wounded with a sterile needle and inoculated with conidial suspension (10 conidia/mL). Three control plants were sprayed with sterile water. Seedlings were covered with plastic bags after inoculation and kept in a greenhouse at 25 ± 2°C and RH 80%. Seven days after inoculation, all inoculated leaves were reddish brown and withered like those observed in the field, whereas the control plants remained symptomless. was successfully reisolated from the infected tissues. This pathogen has been reported to cause leaf blight on many other hosts, such as and macadamia, but in recent years, the disease has also been reported on flowers, such as Anthurium. It has not been reported on and . This is the first report of infecting × in the world. These data will help select appropriate fungicides for managing this newly emerging disease.
PubMed: 35394337
DOI: 10.1094/PDIS-02-22-0444-PDN -
Marine Drugs Mar 2022Four new dimeric sorbicillinoids (- and ) and a new monomeric sorbicillinoid () as well as six known analogs (-) were purified from the fungal strain H8, which was...
Four new dimeric sorbicillinoids (- and ) and a new monomeric sorbicillinoid () as well as six known analogs (-) were purified from the fungal strain H8, which was obtained from mangrove sediment, and showed potent inhibitory activity against the tea pathogenic fungus (). The planar structures of - were assigned by analyses of their UV, IR, HR-ESI-MS, and NMR spectroscopic data. All the compounds were evaluated for growth inhibition of tea pathogenic fungus . Compounds , , , , and exhibited more potent inhibitory activities compared with the positive control hexaconazole with an ED of 24.25 ± 1.57 µg/mL. The ED values of compounds , , , , and were 9.13 ± 1.25, 2.04 ± 1.24, 18.22 ± 1.29, 1.83 ± 1.37, and 4.68 ± 1.44 µg/mL, respectively. Additionally, the effects of these compounds on zebrafish embryo development were also evaluated. Except for compounds and , which imparted toxic effects on zebrafish even at 0.625 μM, the other isolated compounds did not exhibit significant toxicity to zebrafish eggs, embryos, or larvae. Taken together, sorbicillinoid derivatives (, , and ) from H8 displayed low toxicity and high anti-tea pathogenic fungus potential.
Topics: Animals; Ascomycota; Biological Control Agents; Camellia sinensis; Embryo, Nonmammalian; Hypocreales; Molecular Structure; Polyketides; Zebrafish
PubMed: 35323512
DOI: 10.3390/md20030213 -
MSystems Apr 2022Symbiosis with bacteria is widespread among eukaryotes, including fungi. Bacteria that live within fungal mycelia (endohyphal bacteria) occur in many plant-associated...
Transcriptional Profiles of a Foliar Fungal Endophyte (, Ascomycota) and Its Bacterial Symbiont (, ) Reveal Sulfur Exchange and Growth Regulation during Early Phases of Symbiotic Interaction.
Symbiosis with bacteria is widespread among eukaryotes, including fungi. Bacteria that live within fungal mycelia (endohyphal bacteria) occur in many plant-associated fungi, including diverse Mucoromycota and Dikarya. sp. strain 9143 is a filamentous ascomycete isolated originally as a foliar endophyte of Platycladus orientalis (Cupressaceae). It is infected naturally with the endohyphal bacterium sp. strain 9143, which influences auxin and enzyme production by its fungal host. Previous studies have used transcriptomics to examine similar symbioses between endohyphal bacteria and root-associated fungi such as arbuscular mycorrhizal fungi and plant pathogens. However, currently there are no gene expression studies of endohyphal bacteria of Ascomycota, the most species-rich fungal phylum. To begin to understand such symbioses, we developed methods for assessing gene expression by sp. and sp. when grown in coculture and when each was grown axenically. Our assays showed that the density of sp. in coculture was greater than in axenic culture, but the opposite was true for sp. Dual-transcriptome sequencing (RNA-seq) data demonstrate that growing in coculture modulates developmental and metabolic processes in both the fungus and bacterium, potentially through changes in the balance of organic sulfur via methionine acquisition. Our analyses also suggest an unexpected, potential role of the bacterial type VI secretion system in symbiosis establishment, expanding current understanding of the scope and dynamics of fungal-bacterial symbioses. Interactions between microbes and their hosts have important outcomes for host and environmental health. Foliar fungal endophytes that infect healthy plants can harbor facultative endosymbionts called endohyphal bacteria, which can influence the outcome of plant-fungus interactions. These bacterial-fungal interactions can be influential but are poorly understood, particularly from a transcriptome perspective. Here, we report on a comparative, dual-RNA-seq study examining the gene expression patterns of a foliar fungal endophyte and a facultative endohyphal bacterium when cultured together versus separately. Our findings support a role for the fungus in providing organic sulfur to the bacterium, potentially through methionine acquisition, and the potential involvement of a bacterial type VI secretion system in symbiosis establishment. This work adds to the growing body of literature characterizing endohyphal bacterial-fungal interactions, with a focus on a model facultative bacterial-fungal symbiosis in two species-rich lineages, the Ascomycota and .
Topics: Symbiosis; Endophytes; Pestalotiopsis; Gammaproteobacteria; Type VI Secretion Systems; Ascomycota; Bacteria; Fungi, Unclassified; Xanthomonadaceae; Plants; Methionine
PubMed: 35293790
DOI: 10.1128/msystems.00091-22 -
Molecules (Basel, Switzerland) Feb 2022In Mexico, the mango crop is affected by anthracnose caused by species. In the search for environmentally friendly fungicides, chitosan has shown antifungal activity....
In Mexico, the mango crop is affected by anthracnose caused by species. In the search for environmentally friendly fungicides, chitosan has shown antifungal activity. Therefore, fungal isolates were obtained from plant tissue with anthracnose symptoms from the state of Guerrero in Mexico and identified with the ITS and β-Tub genetic markers. Isolates of the complex were again identified with the markers ITS, Act, β-Tub, GADPH, CHS-1, CaM, and ApMat. Commercial chitosan (Aldrich, lot # STBF3282V) was characterized, and its antifungal activity was evaluated on the radial growth of the fungal isolates. The isolated anthracnose-causing species were , , , and . Other fungi found were sp., , sp., sp., , , and . Chitosan showed 78% deacetylation degree and a molecular weight of 32 kDa. Most of the species and the other identified fungi were susceptible to 1 g L chitosan. However, two isolates were less susceptible to chitosan. Although chitosan has antifungal activity, the interactions between species of the complex and their effect on chitosan susceptibility should be studied based on genomic changes with molecular evidence.
Topics: Antifungal Agents; Chitosan; Colletotrichum; Mangifera
PubMed: 35209032
DOI: 10.3390/molecules27041244 -
Marine Drugs Feb 2022Demethylincisterol A (Sdy-1), a highly degraded sterol that we previously isolated from Chinese mangrove endophytic sp. HQD-6, exhibits potent antitumor activity...
Demethylincisterol A (Sdy-1), a highly degraded sterol that we previously isolated from Chinese mangrove endophytic sp. HQD-6, exhibits potent antitumor activity towards a variety of cancer cells. In this study, we further verified that Sdy-1 effectively inhibited the proliferation and migration of human liver (HepG2) and cervical cancer (HeLa) cells in vitro and it can induce cell apoptosis and arrest the cell cycle in the G1-phase. Mechanistically, we demonstrated that Sdy-1 executes its function via inhibition of the Wnt/β-catenin signaling pathway. Sdy-1 may not inhibit the Wnt signaling pathway through the cascade reaction from upstream to downstream, but directly acts on β-catenin to reduce its transcription level, thereby reducing the level of β-catenin protein and further reducing the expression of downstream related proteins. The possible interaction between Sdy-1 and β-catenin protein was further confirmed by molecular docking studies. In the nude mouse xenograft model, Sdy-1 can also significantly inhibit tumor growth. These results indicated that Sdy-1 is an efficient inhibitor of the Wnt signaling pathway and is a promising antitumor candidate for therapeutic applications.
Topics: Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Carcinoma, Hepatocellular; Cell Cycle Checkpoints; Cell Movement; Cell Proliferation; Female; HeLa Cells; Hep G2 Cells; Humans; Liver Neoplasms; Mice; Mice, Nude; Molecular Docking Simulation; Rhizophoraceae; Sterols; Uterine Cervical Neoplasms; Wnt Signaling Pathway; Xenograft Model Antitumor Assays
PubMed: 35200654
DOI: 10.3390/md20020125