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1.
Arch Virol ; 169(8): 161, 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38981885

ABSTRACT

Here, we report a novel ourmia-like mycovirus, named "Phomopsis asparagi magoulivirus 1" (PaMV1), derived from the phytopathogenic fungus Phomopsis asparagi. The genome of PaMV1 consists of a positive-sense single-stranded RNA (+ ssRNA) that is 2,639 nucleotides in length, with a GC content of 57.13%. It contains a single open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) consisting of 686 amino acids with a molecular mass of 78.57 kDa. Phylogenetic analysis based on RdRp sequences revealed that PaMV1 grouped together with Diaporthe gulyae magoulivirus 1 (DgMV1) in a distinct clade. Sequence comparisons and phylogenetic analysis suggest that PaMV1 is a novel member of the genus Magoulivirus, family Botourmiaviridae.


Subject(s)
Fungal Viruses , Genome, Viral , Open Reading Frames , Phomopsis , Phylogeny , RNA, Viral , Fungal Viruses/genetics , Fungal Viruses/classification , Fungal Viruses/isolation & purification , Phomopsis/virology , RNA, Viral/genetics , Whole Genome Sequencing , RNA-Dependent RNA Polymerase/genetics , Base Composition , Plant Diseases/microbiology , Plant Diseases/virology , Viral Proteins/genetics , Base Sequence , RNA Viruses/genetics , RNA Viruses/isolation & purification , RNA Viruses/classification
2.
Mar Drugs ; 22(3)2024 Feb 23.
Article in English | MEDLINE | ID: mdl-38535443

ABSTRACT

The co-culture strategy, which mimics natural ecology by constructing an artificial microbial community, is a useful tool for the activation of biosynthetic gene clusters (BGCs) to generate new metabolites, as well as to increase the yield of respective target metabolites. As part of our project aiming at the discovery of structurally novel and biologically active natural products from mangrove endophytic fungi, we selected the co-culture of a strain of Phomopsis asparagi DHS-48 with another Phomopsis genus fungus DHS-11, both endophyted in mangrove Rhizophora mangle considering the impart of the taxonomic criteria and ecological data. The competition interaction of the two strains was investigated through morphology observation and scanning electron microscopy (SEM), and it was found that the mycelia of the DHS-48 and DHS-11 compacted and tangled with each other with an interwoven pattern in the co-culture system. A new approach that integrates HPLC chromatogram, 1HNMR spectroscopy, UPLC-MS-PCA, and molecular networking enabled the targeted isolation of the induced metabolites, including three new dimeric xanthones phomoxanthones L-N (1-3), along with six known analogs (4-9). Their planar structures were elucidated by an analysis of their HRMS, MS/MS, and NMR spectroscopic data and the absolute configurations based on ECD calculations. These metabolites showed broad cytotoxic activity against the cancer cells assessed, of which compounds 7-9 displayed significant cytotoxicity towards human liver cells HepG-2 with IC50 values ranging from 4.83 µM to 12.06 µM. Compounds 1-6 exhibited weak immunosuppressive activity against the proliferation of ConA-induced (T-cell) and LPS-induced (B-cell) murine splenic lymphocytes. Therefore, combining co-cultivation with a metabolomics-guided strategy as a discovery tool will be implemented as a systematic strategy for the quick discovery of target bioactive compounds.


Subject(s)
Phomopsis , Tandem Mass Spectrometry , Humans , Animals , Mice , Chromatography, Liquid , Coculture Techniques , Fungi
3.
Mar Drugs ; 22(8)2024 Jul 24.
Article in English | MEDLINE | ID: mdl-39195448

ABSTRACT

Co-cultivation is a powerful emerging tool for awakening biosynthetic gene clusters (BGCs) that remain transcriptionally silent under artificial culture conditions. It has recently been used increasingly extensively to study natural interactions and discover new bioactive metabolites. As a part of our project aiming at the discovery of structurally novel and biologically active natural products from mangrove endophytic fungi, an established co-culture of a strain of Phomopsis asparagi DHS-48 with another Phomopsis genus fungus DHS-11, both endophytes in mangrove Rhizophora mangle, proved to be very efficient to induce the production of new metabolites as well as to increase the yields of respective target metabolites. A detailed chemical investigation of the minor metabolites produced by the co-culture of these two titled fungal strains led to the isolation of six alkaloids (1-6), two sterols (7, 8), and six polyketides (9-14). In addition, all the compounds except 8 and 10, as well as three new metabolites phomopyrazine (1), phomosterol C (7), and phomopyrone E (9), were not present in discrete fungal cultures and only detected in the co-cultures. The structures were elucidated on the basis of spectroscopic analysis, and the absolute configurations were assumed by electronic circular dichroism (ECD) calculations. Subsequently, the cytotoxic, immunosuppressive, and acetylcholinesterase inhibitory properties of all the isolated metabolites were determined in vitro. Compound 8 exhibited moderate inhibitory activity against ConA-induced T and LPS-induced B murine splenic lymphocytes, with IC50 values of 35.75 ± 1.09 and 47.65 ± 1.21 µM, respectively.


Subject(s)
Coculture Techniques , Endophytes , Phomopsis , Rhizophoraceae , Animals , Mice , Alkaloids/pharmacology , Alkaloids/isolation & purification , Alkaloids/chemistry , Biological Products/pharmacology , Biological Products/chemistry , Biological Products/isolation & purification , Cholinesterase Inhibitors/pharmacology , Cholinesterase Inhibitors/isolation & purification , Endophytes/metabolism , Phomopsis/metabolism , Polyketides/metabolism , Polyketides/pharmacology , Polyketides/isolation & purification , Polyketides/chemistry , Rhizophoraceae/microbiology , Secondary Metabolism
4.
Plant Dis ; 108(6): 1740-1749, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38219009

ABSTRACT

Phomopsis stem canker of cultivated sunflower (Helianthus annuus L.) can be caused by multiple necrotrophic fungi in the genus Diaporthe, with Diaporthe helianthi and D. gulyae being the most common causal agents in the United States. Infection begins at the leaf margins and proceeds primarily through the vasculature, progressing from the leaf through the petiole to the stem, resulting in formation of brown stem lesions centered around the petiole. Sunflower resistance to Phomopsis stem canker is quantitative and genetically complex. Due to the intricate disease process, resistance is possible at different stages of infection, and multiple forms of defense may contribute to the overall level of quantitative resistance. In this study, sunflower lines exhibiting field resistance to Phomopsis stem canker were evaluated for stem and leaf resistance to multiple isolates of D. helianthi and D. gulyae in greenhouse experiments, and responses to the two species were compared. Additionally, selected resistant and susceptible lines were evaluated for petiole transmission resistance to D. helianthi. Lines with distinct forms of resistance were identified, and results indicated that responses to stem inoculation were strongly correlated (Spearman's coefficient 0.598, P < 0.001) for the two fungal species, while leaf responses were not (Spearman's coefficient 0.396, P = 0.076). These results provide a basis for genetic dissection of distinct forms of sunflower resistance to Phomopsis stem canker and will facilitate combining different forms of resistance to potentially achieve durable control of this disease in sunflower hybrids.


Subject(s)
Helianthus , Phomopsis , Plant Diseases , Helianthus/microbiology , Helianthus/physiology , Plant Diseases/microbiology , Plant Stems/microbiology , Disease Resistance
5.
J Asian Nat Prod Res ; 26(4): 534-540, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37639617

ABSTRACT

Based on the One Strain-Many Compounds (OSMAC) strategy, the secondary metabolites of Phomopsis lithocarpus FS508 were investigated. As a result, a new secondary metabolite, 4-methoxy-3-[4-(acetyloxy)-3-methyl-2-butenyl]benzoic acid (1) as well as eleven known compounds were isolated from the fermentation product of the strain FS508. Their structures were determined by NMR, IR, UV, and MS spectroscopic data analyses. All the isolated compounds were evaluated for cytotoxic and anti-inflammatory activities. Among them, compounds 3 and 9 displayed potent cytotoxicity against HepG-2 cell line, and compounds 2, 3 and 12 showed significant anti-inflammatory activities.


Subject(s)
Antineoplastic Agents , Ascomycota , Phomopsis , Ascomycota/chemistry , Cell Line, Tumor , Antineoplastic Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Molecular Structure
6.
Mol Plant Microbe Interact ; 36(1): 47-58, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36282555

ABSTRACT

The pathogenic fungus Phomopsis longicolla causes numerous plant diseases, such as Phomopsis seed decay, pod and stem blight, and stem canker, which seriously affect the yield and quality of soybean production worldwide. Because of a lack of technology for efficient manipulation of genes for functional genomics, understanding of P. longicolla pathogenesis is limited. Here, we developed an efficient polyethylene glycol-mediated protoplast transformation system in P. longicolla that we used to characterize the functions of two genes involved in the cell wall integrity (CWI) pathway of the mitogen-activated protein kinase (MAPK) cascade, including PlMkk1, which encodes MAPK kinase, and its downstream gene PlSlt2, which encodes MAPK. Both gene knockout mutants ΔPlMkk1 and ΔPlSlt2 displayed a reduced growth rate, fragile aerial hyphae, abnormal polarized growth and pigmentation, defects in sporulation, inadequate CWI, enhanced sensitivity to abiotic stress agents, and significant deficiencies in virulence, although there were some differences in degree. The results suggest that PlMkk1 and PlSlt2 are crucial for a series of growth and development processes as well as pathogenicity. The developed transformation system will be a useful tool for additional gene function research and will aid in the elucidation of the pathogenic mechanisms of P. longicolla. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Subject(s)
Ascomycota , Phomopsis , Ascomycota/genetics , Cell Wall/metabolism
7.
Microb Pathog ; 179: 106114, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37060966

ABSTRACT

The pathogen Phomopsis vexans causes leaf blight, fruit rot, and damping off in brinjal plants, all of which are extremely detrimental. The pathogen affects host plant photosynthetic efficiency and fruit quantity and quality. An appreciation of the pathogenicity of P. vexans is essential for the effective control of infections in the field. Consequently, the goal of this study was to characterise P. vexans in terms of their biochemistry, molecular diversity, and pathogenicity. In terms of cellulase (97.7 U), catalase (12.2 U), and ascorbate peroxidase (147.3 U) activity, isolate PV1 performed best, followed by PV5 (CL-97.0 U, CAT-11.1 U and APX-144.4 U), and PV8 (CL-88.8 U, CAT-9.8 U and APX-141.9 U). In a greenhouse pathogenicity test, isolate PV1 had the highest incidence (97%) and severity (88.6%) of disease, whereas isolate PV6 showed the lowest incidence (57.2%) and severity (70%) of disease. The biochemical enzyme activity of P. vexans corresponds well with its greenhouse pathogenicity results, and its combination can be exploited to identify pathogenic P. vexans isolates. Using RAPD and ISSR primers, molecular characterisation indicated genetic diversity but could not distinguish isolates by geographical origin or pathogenicity. The pathogen P. vexans was verified by ITS1 and ITS4 molecular analysis, and the sequences were subsequently deposited in the NCBI database. In conclusion, the enzyme activity relevant to pathogenicity (CL, CAT and APX) in conjunction with the invivo pathogenicity assay might be utilised to differentiate between pathogenic (virulent) and non-pathogenic (avirulent) P. vexans isolates and develop suitable disease management strategies.


Subject(s)
Solanum melongena , Fruit , Random Amplified Polymorphic DNA Technique , Phomopsis
8.
Mar Drugs ; 21(12)2023 Dec 07.
Article in English | MEDLINE | ID: mdl-38132952

ABSTRACT

Six previously undescribed cytosporone derivatives (phomotones A-E (1-5) and phomotone F (13)), two new spiro-alkanol phombistenes A-B (14-15), and seven known analogs (6-12) were isolated from the mangrove endophytic fungus Phomopsis sp. QYM-13. The structures of these compounds were elucidated using spectroscopic data analysis, electronic circular dichroism (ECD), and 13C NMR calculations. Compound 14 features an unprecedented 1,6-dioxaspiro[4.5]decane ring system. All isolates were evaluated for their inhibitory effect on nitric oxide (NO) in LPS-induced RAW264.7 cells. The results showed that compounds 1, 6, 8, and 11 exhibited potent bioactivities by comparing with positive control. Then, compound 1 displayed the anti-inflammatory effect by inhibiting the MAPK/NF-κB signaling pathways. Molecular docking further revealed the possible mechanism of compound 1 interaction with ERK protein.


Subject(s)
Fungi , Phomopsis , Molecular Docking Simulation , Anti-Inflammatory Agents/pharmacology , Signal Transduction , Molecular Structure
9.
Chem Biodivers ; 20(7): e202300275, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37317928

ABSTRACT

Microorganisms produce a wealth of structurally diverse specialized metabolites with a remarkable range of biological activities. The Phomopsis sp. LGT-5 was obtained through tissue block and repeatedly crossed methods from Tripterygium wilfordii Hook. F. The antibacterial experiments of LGT-5 showed that it has high inhibitory activity against Staphylococcus aureus and Pseudomonas aeruginosa, and moderate inhibitory activity against Candida albicans. To research the generation of the antibacterial phenomenon of LGT-5 and provide support for further research and application, the whole genome sequencing (WGS) of LGT-5 was obtained by single-molecule real-time DNA sequencing platform Pacific Biosciences (PacBio) sequencing and Illumina paired-end sequencing. The final assembled LGT-5 genome is 54.79 Mb with a contig N50 of 290.07 kb; in addition, its secondary metabolites were detected through HPLC-Q-ToF-MS/MS. By comparing its MS/MS data, the secondary metabolites were analyzed based on visual network maps obtained on the Global Natural Products Social Molecular Networking (GNPS). The analysis results showed that the secondary metabolites of LGT-5 were triterpenes and various cyclic dipeptides.


Subject(s)
Phomopsis , Tandem Mass Spectrometry , Chromatography, High Pressure Liquid , Whole Genome Sequencing , Sequence Analysis, DNA
10.
Plant Dis ; 107(3): 743-749, 2023 Mar.
Article in English | MEDLINE | ID: mdl-35914292

ABSTRACT

Phomopsis stem canker reduces yield of sunflower (Helianthus annuus L.) up to or exceeding 40%; however, management recommendations have not been developed for U.S. farmers. Between 2009 and 2020, foliar fungicide trials were conducted in Minnesota, Nebraska, North Dakota, and South Dakota for a total of 49 location-years. Random effects meta-analyses were performed on the disease severity index (DSI) and yield data collected from the foliar fungicide trials to determine the overall and individual effectiveness of the tested fungicides. Effect sizes, Cohen's f or Hedges' g, were calculated as the difference in DSI or yield between the fungicide treatment and nontreated control (NTC) divided by the pooled SD. The pooled Cohen's f for DSI and yield was 0.40 (95% CI = [0.29, 0.42]), indicating a large effect size and that fungicide treatments had a significant effect on DSI and yield (P < 0.0001). Among the fungicide groups, quinone outside inhibitor (QoI) (DSI [k = 45; g = -0.47] and yield [k = 46; g = 0.41]) is moderately effective and premixes of demethylation inhibitors (DMI), succinate dehydrogenase inhibitors (SDHI), and QoI (DMI + SDHI + QoI) (DSI [k = 3; g = -0.79] and yield [k = 3; g = 0.94]) are largely effective in comparison with NTC. Upon performing prediction analyses, the probability of not recovering the fungicide application cost (Ploss) associated with QoI (pyraclostrobin) was <0.35 for a range of sunflower grain prices suggesting a greater probability of return on investment from a single application of fungicide. Overall, our study suggests that the use of QoI fungicides is likely to be profitable in the presence of Phomopsis stem canker (DSI > 5%).


Subject(s)
Fungicides, Industrial , Helianthus , Fungicides, Industrial/pharmacology , Phomopsis , Plant Diseases/prevention & control , Minnesota
11.
Molecules ; 28(9)2023 Apr 27.
Article in English | MEDLINE | ID: mdl-37175165

ABSTRACT

Mangrove-associated fungi are important sources for the discovery of new bioactive natural products. Three new isocoumarins (1-3) and one new pyrone derivative (4) were isolated from the ethyl acetate extract of the fermentation broth of the mangrove endophytic fungus Phomopsis sp. DHS-11. Nuclear magnetic resonance (NMR) spectroscopy (one-dimensional and two-dimensional) and mass spectrometry were used to determine the structures of these new compounds. The absolute configurations for the new isocoumarins 1-3 were determined by comparing their experimental and calculated electronic circular dichroism (ECD) spectra, while the configuration for the new pyrone-derivative 4 was tentatively solved by comparison of its 13C NMR data with reported data. In the biological activity test, compounds 1 and 3 showed cytotoxic activity against HeLa cells with IC50 values of 11.49 ± 1.64 µM and 8.70 ± 0.94 µM, respectively. The initial structure and activity relationship (SAR) analysis revealed that the length of the side chain at C-3 for isocoumarin-type compounds 1-3 could affect the cytotoxicity against HeLa cells. Compound 4 exhibited cytotoxic activities against human hepatoma cells HepG2 with an IC50 value of 34.10 ± 2.92 µM. All compounds have no immunosuppressive activity.


Subject(s)
Antineoplastic Agents , Rhizophoraceae , Humans , Antineoplastic Agents/pharmacology , Fungi , HeLa Cells , Isocoumarins/chemistry , Molecular Structure , Phomopsis , Pyrones/pharmacology , Rhizophoraceae/microbiology
12.
World J Microbiol Biotechnol ; 39(9): 237, 2023 Jul 01.
Article in English | MEDLINE | ID: mdl-37391650

ABSTRACT

Phomopsis canker is one of the major devastating stem diseases that occur in tea plants caused by the fungal pathogen Phomopsis theae. Rapid development of this disease leads to a capital loss in the tea industry which demands an ecofriendly disease management strategy to control this aggressive pathogen. A total of 245 isolates were recovered from the tea rhizosphere and screened for in vitro plant growth promoting (PGP) traits and antagonism against P. theae. Among them, twelve isolates exhibited multifarious PGP traits including phytohormones, siderophore, hydrogen cyanide, salicylic acid production, phosphate solubilization, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, and antifungal activity. In vitro studies on morphological, biochemical, and phylogenetic analyses classified the selected isolates as Pseudomonas fluorescens (VPF5), Bacillus subtilis (VBS3), Streptomyces griseus (VSG4) and Trichoderma viride (VTV7). Specifically, P. fluorescens VPF5 and B. subtilis VBS3 strains showed the highest level of PGP activities. On the other hand, VBS3 and VTV7 strains showed higher biocontrol efficacy in inhibiting mycelia growth and spore germination of P. theae. A detailed investigation on hydrolytic enzymes produced by antagonistic strains, which degrade the fungus cell wall, revealed that highest amount of chitinase and ß-1,3- glucanase in VTV7 and VBS3 strains. Further, the key antifungal secondary metabolites from these biocontrol agents associated with suppression of P. theae were identified using gas chromatography mass spectrometry. The above study clearly recognized the specific traits in the isolated microbes, which make them good candidates as plant growth-promoting rhizobacteria (PGPR) and biocontrol agents to improve plant growth and health. However, greenhouse trials and field application of these beneficial microbes is required to further confirm their efficacy for the management of stem canker in tea cultivation.


Subject(s)
Antifungal Agents , Camellia sinensis , Antifungal Agents/pharmacology , Phomopsis , Phylogeny , Tea
13.
J Nat Prod ; 85(5): 1229-1238, 2022 05 27.
Article in English | MEDLINE | ID: mdl-35473314

ABSTRACT

Twelve new cytochalasins, phomopchalasins D-O (1-3, 5-12, and 14), including one brominated (2) and two iodinated cytochalasins (3 and 6), together with six known analogues (4, 13, and 15-18) were isolated from the mangrove-derived fungus Phomopsis sp. QYM-13 treated with 3% NaBr or 3% KI in potato liquid medium. Their structures and absolute configurations were established by extensive spectroscopic analysis (1D and 2D NMR, HRESIMS), electronic circular dichroism calculations, and a single-crystal X-ray diffraction experiment. Compounds 3 and 6 represent the first iodinated cytochalasins. Compounds 2, 15, 17, and 18 exhibited significant cytotoxicity against human cancer cell line MDA-MB-435 with IC50 values ranging from 0.2 to 8.2 µM.


Subject(s)
Antineoplastic Agents , Iodine , Antineoplastic Agents/chemistry , Bromine , Cytochalasins/chemistry , Fungi , Humans , Molecular Structure , Phomopsis
14.
Mar Drugs ; 20(8)2022 Aug 18.
Article in English | MEDLINE | ID: mdl-36005528

ABSTRACT

Three new cytochalasins, phomoparagins A-C (1-3), along with five known analogs (4-8), were isolated from Phomopsis asparagi DHS-48, a mangrove-derived endophytic fungus. Their structures, including their absolute configurations, were elucidated using a combination of detailed HRESIMS, NMR, and ECD techniques. Notably, 1 possessed an unprecedented 5/6/5/8/5-fused pentacyclic skeleton. These compounds were tested for their inhibitory activity against concanavalin A (ConA)/lipopolysaccharide (LPS)-induced spleen lymphocyte proliferation and calcineurin (CN) enzyme. Several metabolites (2 and 4-6) exhibited fascinating inhibitory activities with a relatively low toxicity. Furthermore, 2 was demonstrated to inhibit ConA-stimulated activation of NFAT1 dephosphorylation and block NFAT1 translocation in vitro, subsequently inhibiting the transcription of interleukin-2 (IL-2). Our results provide evidence that 2 may, at least partially, suppress the activation of spleen lymphocytes via the CN/NFAT signaling pathway, highlighting that it could serve as an effective immunosuppressant that is noncytotoxic and natural.


Subject(s)
Cytochalasins , Fungi , Cytochalasins/pharmacology , Immunosuppressive Agents/pharmacology , Molecular Structure , Phomopsis
15.
Chem Biodivers ; 19(8): e202200491, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35707944

ABSTRACT

Chemical investigation of the endophytic fungus Phomopsis asparagi LSLYZ-87 cultured on PDB medium led to the isolation of two new pyrone derivatives, phomasparapyrone A (1), and phomasparapyrone B (2), together with the known kojic acid (3). Their planar structures were connected through 1D and 2D NMR spectroscopic data. And the stereo structures of 1 and 2 were defined by comparison of the experimental ECD spectra to calculated one. All isolates were evaluated for their anti-neuroinflammatory activities. Among them, compound 2 showed moderate inhibition on NO accumulation induced by LPS on BV-2 cells in a dose dependent manner at 30, 40 and 50 µM, and without cytotoxicity in a concentration of 50.0 µM.


Subject(s)
Fungi , Pyrones , Magnetic Resonance Spectroscopy , Molecular Structure , Phomopsis , Pyrones/chemistry , Pyrones/pharmacology
16.
Mol Plant Microbe Interact ; 34(7): 842-844, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33630650

ABSTRACT

Diaporthe-Phomopsis disease complex causes considerable yield losses in soybean production worldwide. As one of the major pathogens, Phomopsis longicolla T. W. Hobbs (syn. Diaporthe longicolla) is not only the primary agent of Phomopsis seed decay but is also one of the agents of Phomopsis pod and stem blight and Phomopsis stem canker. We performed both PacBio long-read sequencing and Illumina short-read sequencing and obtained a genome assembly for the strain P. longicolla YC2-1, which was isolated from soybean stem with Phomopsis stem blight disease. The 63.1 Mb genome assembly contains 87 scaffolds, with a minimum, maximum, and N50 scaffold length of 20 kb, 4.6 Mb, and 1.5 Mb respectively, and a total of 17,407 protein-coding genes. The high-quality data expand the genomic resource of P. longicolla species and will provide a solid foundation for a better understanding of their genetic diversity and pathogenic mechanisms.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Subject(s)
Ascomycota , Glycine max , Ascomycota/genetics , Phomopsis , Seeds
17.
J Exp Bot ; 72(8): 3320-3336, 2021 04 02.
Article in English | MEDLINE | ID: mdl-33544825

ABSTRACT

Phomopsis. longicolla is a hemibiotrophic fungus causing significant soybean yield loss worldwide. To reveal the role of zinc in plant-pathogen interactions, soybean seedlings were grown hydroponically with a range of Zn concentrations, 0.06 µM (deficient, Zn0), 0.4 µM (optimal growth), 1.5 µM, 4 µM, 12 µM, and toxic 38 µM, and were subsequently inoculated with P. longicolla via the roots. In vivo analysis of metal distribution in tissues by micro-X-ray fluorescence showed local Zn mobilization in the root maturation zone in all treatments. Decreased root and pod biomass, and photosynthetic performance in infected plants treated with 0.4 µM Zn were accompanied with accumulation of Zn, jasmonoyl-L-isoleucine (JA-Ile), jasmonic acid, and cell wall-bound syringic acid (cwSyA) in roots. Zn concentration in roots of infected plants treated with 1.5 µM Zn was seven-fold higher than in the 0.4 µM Zn treatment, which together with accumulation of JA-Ile, cwSyA, cell wall-bound vanilic acid and leaf jasmonates contributed to maintaining photosynthesis and pod biomass. Host-pathogen nutrient competition and phenolics accumulation limited the infection in Zn-deficient plants. The low infection rate in Zn 4 µM-treated roots correlated with salicylic and 4-hydroxybenzoic acid, and cell wall-bound p-coumaric acid accumulation. Zn toxicity promoted pathogen invasion and depleted cell wall-bound phenolics. The results show that manipulation of Zn availability improves soybean resistance to P. longicolla by stimulating phenolics biosynthesis and stress-inducible phytohormones.


Subject(s)
Glycine max , Zinc , Phomopsis , Plant Roots , Seedlings
18.
Theor Appl Genet ; 134(1): 249-259, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33106896

ABSTRACT

KEY MESSAGE: We provide results rooted in quantitative genetics, which combined with knowledge of candidate gene function, helps us to better understand the resistance to two major necrotrophic pathogens of sunflower. Necrotrophic pathogens can avoid or even benefit from plant defenses used against biotrophic pathogens, and thus represent a distinct challenge to plant populations in natural and agricultural systems. Sclerotinia and Phomopsis/Diaporthe are detrimental pathogens for many dicotyledonous plants, including many economically important plants. With no well-established methods to prevent infection in susceptible plants, host-plant resistance is currently the most effective strategy. Despite knowledge of a moderate, positive correlation in resistance to the two diseases in sunflower, detailed analysis of the genetics, in the same populations, has not been conducted. We present results of genome-wide analysis of resistance to both pathogens in a diversity panel of 218 domesticated sunflower genotypes of worldwide origin. We identified 14 Sclerotinia head rot and 7 Phomopsis stem canker unique QTLs, plus 1 co-located QTL for both traits, and observed extensive patterns of linkage disequilibrium between sites for both traits. Most QTLs contained one credible candidate gene, and gene families were common for the two disease resistance traits. These results suggest there has been strong, simultaneous selection for resistance to these two diseases and that a generalized mechanism for defense against these necrotrophic pathogens exists.


Subject(s)
Ascomycota/pathogenicity , Disease Resistance/genetics , Helianthus/genetics , Phomopsis/pathogenicity , Plant Diseases/genetics , Quantitative Trait Loci , Genotype , Helianthus/microbiology , Linkage Disequilibrium , Phenotype , Plant Diseases/microbiology , Selection, Genetic
19.
Arch Microbiol ; 203(10): 6215-6229, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34609529

ABSTRACT

The endophytic fungus Phomopsis liquidambaris is characterized as a plant growth-promoting agent under salt stress, but its mechanism is unknown. Herein, 1-aminocyclopropane-1-carboxylate deaminase (ACCD) from the strain was confirmed that it had the ability of utilizing 1-aminocyclopropane-1-carboxylate as the sole nitrogen source. The full-length ACCD gene was 1152 bp, which encodes a mature protein of 384 amino acids with a molecular mass of 41.53 kDa. The ACCD activity was 3.9-fold in 3 mmol L-1 ACC by qRT-PCR under salt stress comparing with no salt tress. Ethylene production was increased to 34.55-70.60% and reduced the growth of rice by 23-69.73% under salt stress. Inoculation of P. liquidambaris increased root-shoot length, fresh and dry weight, and overall growth of stressed rice seedlings. ACC accumulation, ACC synthase and ACC oxidase activities increased in salt-treated rice seedlings, while they were significantly reduced when P. liquidambaris was inoculated into rice by qRT-PCR. It therefore can be concluded that P. liquidambaris can be used as a plant growth promoting fungus against salt stress and other biotic or abiotic stresses.


Subject(s)
Oryza , Carbon-Carbon Lyases , Ethylenes , Phomopsis , Salt Stress
20.
Arch Virol ; 166(1): 291-294, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33057930

ABSTRACT

Here, we report the molecular characterization of a novel partitivirus from Phomopsis vexans strain PvHZ002, a plant-pathogenic fungus infecting eggplant. The virus was designated "Phomopsis vexans partitivirus 1" (PvPV1). PvPV1 contains two dsRNA segments, dsRNA1 and dsRNA2, which are 1,662 bp and 1,628 bp long, respectively. Each segment contains a single open reading frame, putatively encoding RNA-dependent RNA polymerase (dsRNA 1) and capsid protein (dsRNA 2). A homology search and phylogenetic analysis showed that PvPV1 clustered with viruses of the genus Deltapartitivirus of the family Partitiviridae.


Subject(s)
Fungal Viruses/genetics , Genome, Viral/genetics , Phomopsis/virology , RNA Viruses/genetics , Amino Acid Sequence , Base Sequence , Capsid Proteins/genetics , Phylogeny , Plant Diseases/virology , RNA, Double-Stranded/genetics , RNA-Dependent RNA Polymerase/genetics , Solanum melongena/virology
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