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Natural Protein Kinase Inhibitors, Staurosporine, and Chelerythrine Suppress Wheat Blast Disease Caused by Magnaporthe oryzae Triticum. Microorganisms 2022; 10:microorganisms10061186. [PMID: 35744705 PMCID: PMC9230996 DOI: 10.3390/microorganisms10061186] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 01/01/2023] Open
Abstract
Protein kinases (PKs), being key regulatory enzymes of a wide range of signaling pathways, are potential targets for antifungal agents. Wheat blast disease, caused by Magnaporthe oryzae Triticum (MoT), is an existential threat to world food security. During the screening process of natural metabolites against MoT fungus, we find that two protein kinase inhibitors, staurosporine and chelerythrine chloride, remarkably inhibit MoT hyphal growth. This study further investigates the effects of staurosporine and chelerythrine chloride on MoT hyphal growth, conidia production, and development as well as wheat blast inhibition in comparison to a commercial fungicide, Nativo®75WG. The growth of MoT mycelia is significantly inhibited by these compounds in a dose-dependent manner. These natural compounds greatly reduce conidia production in MoT mycelia along with suppression of conidial germination and triggered lysis, resulting in deformed germ tubes and appressoria. These metabolites greatly suppress blast development in artificially inoculated wheat plants in the field. This is the first report of the antagonistic effect of these two natural PKC inhibitory alkaloids on MoT fungal developmental processes in vitro and suppression of wheat blast disease on both leaves and spikes in vivo. Further research is needed to identify their precise mechanism of action to consider them as biopesticides or lead compounds for controlling wheat blast.
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van de Vossenberg BTLH, Prodhomme C, Vossen JH, van der Lee TAJ. Synchytrium endobioticum, the potato wart disease pathogen. MOLECULAR PLANT PATHOLOGY 2022; 23:461-474. [PMID: 35029012 PMCID: PMC8916214 DOI: 10.1111/mpp.13183] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 06/14/2023]
Abstract
UNLABELLED Potato wart disease is considered one of the most important quarantine pests for cultivated potato and is caused by the obligate biotrophic chytrid fungus Synchytrium endobioticum. This review integrates observations from early potato wart research and recent molecular, genetic, and genomic studies of the pathogen and its host potato. Taxonomy, epidemiology, pathology, and formation of new pathotypes are discussed, and a model for molecular S. endobioticum-potato interaction is proposed. TAXONOMY Currently classified as kingdom: Fungi, phylum: Chytridiomycota, class: Chytridiomycetes, order: Chytridiales, family: Synchytriaceae, genus: Synchytrium, species: Synchytrium endobioticum, there is strong molecular support for Synchytriaceae to be transferred to the order Synchytriales. HOSTS AND DISEASE SYMPTOMS Solanum tuberosum is the main host for S. endobioticum but other solanaceous species have been reported as alternative hosts. It is not known if these alternative hosts play a role in the survival of the pathogen in (borders of) infested fields. Disease symptoms on potato tubers are characterized by the warty cauliflower-like malformations that are the result of cell enlargement and cell multiplication induced by the pathogen. Meristematic tissue on tubers, stolons, eyes, sprouts, and inflorescences can be infected while the potato root system seems to be immune. PATHOTYPES For S. endobioticum over 40 pathotypes, which are defined as groups of isolates with a similar response to a set of differential potato varieties, are described. Pathotypes 1(D1), 2(G1), 6(O1), and 18(T1) are currently regarded to be most widespread. However, with the current differential set other pathogen diversity largely remains undetected. PATHOGEN-HOST INTERACTION A single effector has been described for S. endobioticum (AvrSen1), which is recognized by the potato Sen1 resistance gene product. This is also the first effector that has been described in Chytridiomycota, showing that in this fungal division resistance also fits the gene-for-gene concept. Although significant progress was made in the last decade in mapping wart disease resistance loci, not all resistances present in potato breeding germplasm could be identified. The use of resistant varieties plays an essential role in disease management.
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Affiliation(s)
| | | | - Jack H. Vossen
- Plant BreedingWageningen University & ResearchWageningenNetherlands
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Amponsah J, Tegg RS, Thangavel T, Wilson CR. Subversion of Phytomyxae Cell Communication With Surrounding Environment to Control Soilborne Diseases; A Case Study of Cytosolic Ca 2+ Signal Disruption in Zoospores of Spongospora subterranea. Front Microbiol 2022; 13:754225. [PMID: 35300485 PMCID: PMC8921600 DOI: 10.3389/fmicb.2022.754225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Ca2+ signaling regulates physiological processes including chemotaxis in eukaryotes and prokaryotes. Its inhibition has formed the basis for control of human disease but remains largely unexplored for plant disease. This study investigated the role of Ca2+ signaling on motility and chemotaxis of Spongospora subterranea zoospores, responsible for root infections leading to potato root and tuber disease. Cytosolic Ca2+ flux inhibition with Ca2+ antagonists were found to alter zoospore swimming patterns and constrain zoospore chemotaxis, root attachment and zoosporangia infection. LaCl3 and GdCl3, both Ca2+ channel blockers, at concentrations ≥ 50 μM showed complete inhibition of zoospore chemotaxis, root attachment and zoosporangia root infection. The Ca2+ chelator EGTA, showed efficient chemotaxis inhibition but had relatively less effect on root attachment. Conversely the calmodulin antagonist trifluoperazine had lesser effect on zoospore chemotaxis but showed strong inhibition of zoospore root attachment. Amiloride hydrochloride had a significant inhibitory effect on chemotaxis, root attachment, and zoosporangia root infection with dose rates ≥ 150 μM. As expected, zoospore attachment was directly associated with root infection and zoosporangia development. These results highlight the fundamental role of Ca2+ signaling in zoospore chemotaxis and disease establishment. Their efficient interruption may provide durable and practical control of Phytomyxea soilborne diseases in the field.
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Affiliation(s)
- Jonathan Amponsah
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, Australia
- Biotechnology and Nuclear Agricultural Research Institute Centre, Ghana Atomic Energy Commission, Accra, Ghana
| | - Robert S. Tegg
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, Australia
| | | | - Calum R. Wilson
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, Australia
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Becking T, Kiselev A, Rossi V, Street-Jones D, Grandjean F, Gaulin E. Pathogenicity of animal and plant parasitic Aphanomyces spp and their economic impact on aquaculture and agriculture. FUNGAL BIOL REV 2021. [DOI: 10.1016/j.fbr.2021.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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5
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Muok AR, Briegel A. Intermicrobial Hitchhiking: How Nonmotile Microbes Leverage Communal Motility. Trends Microbiol 2020; 29:542-550. [PMID: 33160853 DOI: 10.1016/j.tim.2020.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 01/12/2023]
Abstract
Motility allows many microbes to traverse their environment to find nutrient sources or escape unfavorable environments. However, some microbes are nonmotile and are restricted to their immediate conditions. Intriguingly, sporadic reports have demonstrated that many nonmotile microbes can utilize the motility machinery of other microbes in their vicinity. This form of transportation, called hitchhiking, has been observed with both prokaryotic and eukaryotic microbes. Importantly, many hitchhiking microbes are pathogenic to humans or plants. Here, we discuss reports of intermicrobial hitchhiking to generate a comprehensive view of hitchhiking mechanisms and how such interactions may influence human and plant health. We hypothesize that microbial hitchhiking is ubiquitous in nature and may become the subject of an independent subfield of research in microbiology.
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Affiliation(s)
- A R Muok
- Institute for Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands; Centre for Microbial Cell Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
| | - A Briegel
- Institute for Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands; Centre for Microbial Cell Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands.
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Hasegawa T, Okabe A, Kato Y, Ooshiro A, Kawaide H, Natsume M. Ethyl β-d-glucoside: a novel chemoattractant of Ralstonia solanacearum isolated from tomato root exudates by a bioassay-guided fractionation. Biosci Biotechnol Biochem 2018; 82:2049-2052. [DOI: 10.1080/09168451.2018.1515618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
ABSTRACT
A chemoattractant of Ralstonia solanacearum isolated from the activated charcoal-adsorbed fraction of tomato root exudates was identified as ethyl β-d-glucopyranoside by instrumental analyses and comparison with synthetic preparations. Ethyl β-d-glucopyranoside showed unambiguous activity at above 1 µmol/disc. Its stereoisomers and d-glucose were inactive.
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Affiliation(s)
- Takuya Hasegawa
- Department of Biological Production Science, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Atsushi Okabe
- Department of Bioregulation and Biointeraction, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yusuke Kato
- Department of Bioregulation and Biointeraction, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Atsushi Ooshiro
- Okinawa Prefectural Agricultural Research Center, Okinawa, Japan
| | - Hiroshi Kawaide
- Division of Bioregulation and Biointeraction, Institute of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Masahiro Natsume
- Division of Bioregulation and Biointeraction, Institute of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
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Islam MT, Laatsch H, von Tiedemann A. Inhibitory Effects of Macrotetrolides from Streptomyces spp. On Zoosporogenesis and Motility of Peronosporomycete Zoospores Are Likely Linked with Enhanced ATPase Activity in Mitochondria. Front Microbiol 2016; 7:1824. [PMID: 27917156 PMCID: PMC5114239 DOI: 10.3389/fmicb.2016.01824] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/31/2016] [Indexed: 11/25/2022] Open
Abstract
The release of zoospores from sporangia and motility of the released zoospores are critical in the disease cycle of the Peronosporomycetes that cause devastating diseases in plants, fishes, animals and humans. Disruption of any of these asexual life stages eliminates the possibility of pathogenesis. In the course of screening novel bioactive secondary metabolites, we found that extracts of some strains of marine Streptomyces spp. rapidly impaired motility and caused subsequent lysis of zoospores of the grapevine downy mildew pathogen Plasmopara viticola at 10 μg/ml. We tested a number of secondary metabolites previously isolated from these strains and found that macrotetrolide antibiotics such as nonactin, monactin, dinactin and trinactin, and nactic acids such as (+)-nonactic acid, (+)-homonactic acid, nonactic acid methyl ester, homonactic acid methyl ester, bonactin and feigrisolide C impaired motility and caused subsequent lysis of P. viticola zoospores in a dose- and time-dependent manners with dinactin being the most active compound (MIC 0.3 μg/ml). A cation channel-forming compound, gramicidin, and a carrier of monovalent cations, nigericin also showed similar biological activities. Among all 12 compounds tested, gramicidin most potently arrested the motility of zoospores at concentrations starting from 0.1 μg/ml. All macrotetrolide antibiotics also displayed similar motility impairing activities against P. viticola, Phytophthora capsici, and Aphanomyces cochlioides zoospores indicating non-specific biological effects of these compounds toward peronosporomyctes. Furthermore, macrotetrolide antibiotics and gramicidin also markedly suppressed the release of zoospores from sporangia of P. viticola in a dose-dependent manner. As macrotetrolide antibiotics and gramicidin are known as enhancers of mitochondrial ATPase activity, inhibition of zoosporogenesis and motility of zoospores by these compounds are likely linked with hydrolysis of ATP through enhanced ATPase activity in mitochondria. This is the first report on motility inhibitory and lytic activities of macrotetrolide antibiotics and nactic acids against the zoospores of peronosporomycete phytopathogens.
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Affiliation(s)
- Md Tofazzal Islam
- Division of Plant Pathology and Plant Protection, Department of Crop Sciences, Georg-August-Universität GöttingenGöttingen, Germany; Department of Biotechnology, Bangabandhu Sheikh Mujibur Rahman Agricultural UniversityGazipur, Bangladesh
| | - Hartmut Laatsch
- Institute of Organic and Biomolecular Chemistry, Georg-August-Universität Göttingen Göttingen, Germany
| | - Andreas von Tiedemann
- Department of Biotechnology, Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur, Bangladesh
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Balendres MA, Nichols DS, Tegg RS, Wilson CR. Metabolomes of Potato Root Exudates: Compounds That Stimulate Resting Spore Germination of the Soil-Borne Pathogen Spongospora subterranea. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:7466-7474. [PMID: 27640528 DOI: 10.1021/acs.jafc.6b03904] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Root exudation has importance in soil chemical ecology influencing rhizosphere microbiota. Prior studies reported root exudates from host and nonhost plants stimulated resting spore germination of Spongospora subterranea, the powdery scab pathogen of potato, but the identities of stimulatory compounds were unknown. This study showed that potato root exudates stimulated S. subterranea resting spore germination, releasing more zoospores at an earlier time than the control. We detected 24 low molecular weight organic compounds within potato root exudates and identified specific amino acids, sugars, organic acids, and other compounds that were stimulatory to S. subterranea resting spore germination. Given that several stimulatory compounds are commonly found in exudates of diverse plant species, we support observations of nonhost-specific stimulation. We provide knowledge of S. subterranea resting spore biology and chemical ecology that may be useful in formulating new disease management strategies.
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Affiliation(s)
- Mark A Balendres
- New Town Research Laboratories, Tasmanian Institute of Agriculture, University of Tasmania , 13 St. Johns Avenue, New Town, Tasmania 7008, Australia
| | - David S Nichols
- Central Science Laboratory, University of Tasmania , Private Bag 74, Hobart, Tasmania 7001, Australia
| | - Robert S Tegg
- New Town Research Laboratories, Tasmanian Institute of Agriculture, University of Tasmania , 13 St. Johns Avenue, New Town, Tasmania 7008, Australia
| | - Calum R Wilson
- New Town Research Laboratories, Tasmanian Institute of Agriculture, University of Tasmania , 13 St. Johns Avenue, New Town, Tasmania 7008, Australia
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Dame ZT, Islam MT, Helmke E, von Tiedemann A, Laatsch H. Oligomycins and pamamycin homologs impair motility and induce lysis of zoospores of the grapevine downy mildew pathogen,Plasmopara viticola. FEMS Microbiol Lett 2016; 363:fnw167. [DOI: 10.1093/femsle/fnw167] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2016] [Indexed: 11/12/2022] Open
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Meléndez-González C, Murià-González MJ, Anaya AL, Hernández-Bautista BE, Hernández-Ortega S, González MC, Glenn AE, Hanlin RT, Macías-Rubalcava ML. Acremoxanthone E, a Novel Member of Heterodimeric Polyketides with a Bicyclo[3.2.2]nonene Ring, Produced byAcremonium camptosporumW.Gams(Clavicipitaceae) Endophytic Fungus. Chem Biodivers 2015; 12:133-47. [DOI: 10.1002/cbdv.201300370] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Indexed: 10/24/2022]
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Talontsi FM, Facey P, Tatong MDK, Tofazzal Islam M, Frauendorf H, Draeger S, Tiedemann AV, Laatsch H. Zoosporicidal metabolites from an endophytic fungus Cryptosporiopsis sp. of Zanthoxylum leprieurii. PHYTOCHEMISTRY 2012; 83:87-94. [PMID: 22883958 DOI: 10.1016/j.phytochem.2012.06.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 05/11/2012] [Accepted: 06/11/2012] [Indexed: 06/01/2023]
Abstract
Two polyketides, cryptosporiopsin A (1) and hydroxypropan-2',3'-diol orsellinate (3), and a natural cyclic pentapeptide (4), together with two known compounds were isolated from the culture of Cryptosporiopsis sp., an endophytic fungus from leaves and branches of Zanthoxylum leprieurii (Rutaceae). The structures of these metabolites were elucidated on the basis of their spectroscopic and spectrometric data. Cryptosporiopsin A and the other metabolites exhibited motility inhibitory and lytic activities against zoospores of the grapevine downy mildew pathogen Plasmopara viticola at 10-25μg/mL. In addition, the isolated compounds displayed potent inhibitory activity against mycelial growth of two other peronosporomycete phytopathogens, Pythium ultimum, Aphanomyces cochlioides and a basidiomycetous fungus Rhizoctonia solani. Weak cytotoxic activity on brine shrimp larvae was observed.
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Affiliation(s)
- Ferdinand Mouafo Talontsi
- Institute for Organic and Biomolecular Chemistry, Georg-August University, Tammannstrasse 2, D-37077 Göttingen, Germany
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Abdalla MA, Win HY, Islam MT, von Tiedemann A, Schüffler A, Laatsch H. Khatmiamycin, a motility inhibitor and zoosporicide against the grapevine downy mildew pathogen Plasmopara viticola from Streptomyces sp. ANK313. J Antibiot (Tokyo) 2011; 64:655-659. [PMID: 21811263 DOI: 10.1038/ja.2011.68] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the course of our screening for anti-peronosporomycetal agents, we isolated a new compound khatmiamycin (1), together with five known metabolites, GTRI-02 (3), 4-ethyl-5-methyl-heptanamide (4), aloesaponarin II (5), LL-C10037α (6) and LL-C10037β (7) from the culture broth of a terrestrial Streptomyces sp. ANK313. The structures of these metabolites were assigned on the basis of their spectroscopic data. Khatmiamycin (1) exhibited potent motility inhibitory (100%) and lytic (83±7%) activities against zoospores of the grapevine downy mildew pathogen Plasmopara viticola at 10 μg ml(-1), followed by compounds 5 (MIC 25 μg ml(-1)), 7, 6, 3 in the order of decreasing activity. Khatmiamycin (1) also showed potent antibacterial activity against Staphylococcus aureus and Streptomyces viridochromogenes (Tü57) by causing inhibition zones of 11 and 14 mm diameter, respectively, at the dose of 40 μg per disk. This is the first report on motility inhibitory and lytic activities of metabolites from a terrestrial Streptomyces species against the zoospores of downy mildew pathogen P. viticola.
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Affiliation(s)
- Muna Ali Abdalla
- Institute of Organic and Biomolecular Chemistry, Georg-August University Göttingen, Göttingen, Germany
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Islam MT, von Tiedemann A. 2,4-Diacetylphloroglucinol suppresses zoosporogenesis and impairs motility of Peronosporomycete zoospores. World J Microbiol Biotechnol 2011; 27:2071-2079. [PMID: 22448105 PMCID: PMC3291839 DOI: 10.1007/s11274-011-0669-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 01/20/2011] [Indexed: 11/25/2022]
Abstract
2,4-Diacetylphloroglucinol (DAPG) produced by Pseudomonas fluorescens, shows toxicity to many microorganisms including fungi, bacteria, and peronosporomycetes. Zoosporogenesis and motility of zoospores are critical for a complete disease cycle and pathogenicity of the peronosporomycete phytopathogens. The aim of this study was to test the effects of DAPG and its derivatives on zoosporogenesis and motility of zoospores of a downy mildew pathogen, Plasmopara viticola, and a damping-off pathogen, Aphanomyces cochlioides. In both cases, DAPG inhibited zoosporogenesis (5 μg/ml) and the motility of zoospores (10 μg/ml) in a dose-dependent manner. Generally, zoospores became immotile shortly after exposure to DAPG followed by lysis. However, a fraction of DAPG treated A. cochlioides zoospores formed round cystospores instead of lysis and then germinated with excessively-branched germ tubes. All derivatives of DAPG had similar inhibitory activities but at varying doses. Among them, 2,4-dipropylphloroglucinol exerted the highest inhibitory activity against both zoosporogenesis and motility of zoospores. This revealed that the degree of hydrogen atoms substitution in the benzene ring by acyl groups and the length of substituted acyl groups were related to the level of bioactivity. This is the first report of inhibitory activities of DAPG and its derivatives against zoosporogenesis and motility of zoospores of two important peronosporomycete phytopathogens.
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Affiliation(s)
- M. Tofazzal Islam
- Division of Plant Pathology and Plant Protection, University of Göttingen, Grisebachstrasse 6, Göttingen, Germany
- Department of Biotechnology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, 1706 Bangladesh
| | - Andreas von Tiedemann
- Division of Plant Pathology and Plant Protection, University of Göttingen, Grisebachstrasse 6, Göttingen, Germany
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Islam MT. Ultrastructure of Aphanomyces cochlioides zoospores and changes during their developmental transitions triggered by the host-specific flavone cochliophilin A. J Basic Microbiol 2010; 50 Suppl 1:S58-67. [PMID: 20473957 DOI: 10.1002/jobm.200900301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Aphanomyces cochlioides is a serious damping-off causing pathogen of sugar beet, spinach and some other members of Chenopodiaceae and Amaranthaceae. The biflagellated motile zoospores of the pathogen locate their host roots by perceiving the host-specific flavone cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone), transiently modify into cystospores that germinate prior to penetration. This study for the first time illustrated ultrastructure of the zoospores and morphological modification during their developmental transitions triggered by cochliophilin A using transmission electron microscopy (TEM). TEM revealed that zoospores had two heterokont flagella inserted laterally into a ventral groove of their body where each is attached to a kinetosome. In the cross sections of flagellar axonemes, two single and nine peripheral microtubules in doublets were clearly observed. Mitochondria, the Golgi complexes, finger print vesicles, and vesicles with striated electron opaque inclusion and vesicles containing a granular cortex and center were also detected. The latter vesicles disappeared and two flagella were shed when zoospores converted to spherical cystsopores. The shape, size and number of mitochondria were dynamically changed during the encystment of zoospores presumably through fission and fusion processes. The dynamics of mitochondria observed in this study indicated its distinct role in the signal transduction pathway of the zoospore encystment. This study also revealed the transformation of shape of nuclei from pyriform in zoospores to spherical in cystospores and lanceolate in the hyphae.
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Affiliation(s)
- M Tofazzal Islam
- Graduate School of Agriculture, Hokkaido University, Kita-Ku, Sapporo, Japan.
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Islam MT, Fukushi Y. Growth inhibition and excessive branching in Aphanomyces cochlioides induced by 2,4-diacetylphloroglucinol is linked to disruption of filamentous actin cytoskeleton in the hyphae. World J Microbiol Biotechnol 2009; 26:1163-70. [DOI: 10.1007/s11274-009-0284-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 12/12/2009] [Indexed: 10/20/2022]
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Mode of antagonism of a biocontrol bacterium Lysobacter sp. SB-K88 toward a damping-off pathogen Aphanomyces cochlioides. World J Microbiol Biotechnol 2009. [DOI: 10.1007/s11274-009-0216-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Dynamic rearrangement of F‐actin organization triggered by host‐specific plant signal is linked to morphogenesis ofAphanomyces cochlioideszoospores. ACTA ACUST UNITED AC 2008; 65:553-62. [DOI: 10.1002/cm.20281] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Islam MT, Hashidoko Y, Deora A, Ito T, Tahara S. Suppression of damping-off disease in host plants by the rhizoplane bacterium Lysobacter sp. strain SB-K88 is linked to plant colonization and antibiosis against soilborne Peronosporomycetes. Appl Environ Microbiol 2005; 71:3786-96. [PMID: 16000790 PMCID: PMC1169021 DOI: 10.1128/aem.71.7.3786-3796.2005] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously demonstrated that xanthobaccin A from the rhizoplane bacterium Lysobacter sp. strain SB-K88 suppresses damping-off disease caused by Pythium sp. in sugar beet. In this study we focused on modes of Lysobacter sp. strain SB-K88 root colonization and antibiosis of the bacterium against Aphanomyces cochlioides, a pathogen of damping-off disease. Scanning electron microscopic analysis of 2-week-old sugar beet seedlings from seeds previously inoculated with SB-K88 revealed dense colonization on the root surfaces and a characteristic perpendicular pattern of Lysobacter colonization possibly generated via development of polar, brush-like fimbriae. In colonized regions a semitransparent film apparently enveloping the root and microcolonies were observed on the root surface. This Lysobacter strain also efficiently colonized the roots of several plants, including spinach, tomato, Arabidopsis thaliana, and Amaranthus gangeticus. Plants grown from both sugar beet and spinach seeds that were previously treated with Lysobacter sp. strain SB-K88 displayed significant resistance to the damping-off disease triggered by A. cochlioides. Interestingly, zoospores of A. cochlioides became immotile within 1 min after exposure to a SB-K88 cell suspension, a cell-free supernatant of SB-K88, or pure xanthobaccin A (MIC, 0.01 microg/ml). In all cases, lysis followed within 30 min in the presence of the inhibiting factor(s). Our data indicate that Lysobacter sp. strain SB-K88 has a direct inhibitory effect on A. cochlioides, suppressing damping-off disease. Furthermore, this inhibitory effect of Lysobacter sp. strain SB-K88 is likely due to a combination of antibiosis and characteristic biofilm formation at the rhizoplane of the host plant.
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Affiliation(s)
- Md Tofazzal Islam
- Laboratory of Ecological Chemistry, Graduate School of Agriculture, Hokkaido University, Kita-Ku, Sapporo 060-8589, Japan
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Sakihama Y, Shimai T, Sakasai M, Ito T, Fukushi Y, Hashidoko Y, Tahara S. A photoaffinity probe designed for host-specific signal flavonoid receptors in phytopathogenic Peronosporomycete zoospores of Aphanomyces cochlioides. Arch Biochem Biophys 2004; 432:145-51. [PMID: 15542053 DOI: 10.1016/j.abb.2004.09.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Revised: 09/15/2004] [Indexed: 11/28/2022]
Abstract
Aphanomyces cochlioides zoospores show chemotaxis to cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone, 1), a host derived attractant, and also respond to 5,7-dihydroxyflavone (2) known as an equivalent chemoattractant. To investigate the chemotactic receptors in the zoospores, we designed photoaffinity probes 4'-azido-5,7-dihydroxyflavone (3) and 4'-azido-7-O-biotinyl-5-hydroxyflavone (4) considering chemical structure of 2. Both 3 and 4 had zoospore attractant activity which was competitive with that of 1. When zoospores were treated with the biotinylated photoaffinity probe followed by UV irradiation and streptavidin-gold or peroxidase-conjugated streptavidin, probe-labeled proteins were detected on the cell membrane. This result indicated that the 1-specific-binding proteins, a candidate for hypothetical cochliophilin A receptor, were localized on the cell membrane of the zoospores. This is the first experimental evidence of flavonoid-binding proteins being present in zoospores, using chemically synthesized azidoflavone as photoaffinity-labeling reagent.
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Affiliation(s)
- Yasuko Sakihama
- Laboratory of Ecological Chemistry, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo 060-8589, Japan
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MacDonald E, Millward L, Ravishankar JP, Money NP. Biomechanical interaction between hyphae of two Pythium species (Oomycota) and host tissues. Fungal Genet Biol 2002; 37:245-9. [PMID: 12431454 DOI: 10.1016/s1087-1845(02)00514-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Forces exerted by hyphae of the phytopathogen Pythium graminicola and mammalian pathogen Pythium insidiosum were compared with the mechanical resistance of their hosts' tissues. Hyphal apices of both species exerted a mean force of 2 microN, corresponding to mean pressures of 0.19 microN microm(-2) (or MPa) for P. graminicola, and 0.14 microN microm(-2) for P. insidiosum. Experiments with glass microprobes showed that the epidermis of grass roots resisted penetration until the pressure applied at the probe tip reached 1-12 microN microm(-2). Previously published data show that mammalian skin offers even greater resistance (10-47 microN microm(-2)). Clearly, tissue strength exceeds the pressures exerted by hyphae of these pathogens, verifying that secreted enzymes must play a critical role in reducing the resistance of plant and animal tissues. It is presumed that hyphae are sufficiently powerful to bore through any obstacles remaining after enzyme action.
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Affiliation(s)
- Erin MacDonald
- Department of Botany, Miami University, Oxford, OH 45056, USA
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Islam MT, Ito T, Sakasai M, Tahara S. Zoosporicidal activity of polyflavonoid tannin identified in Lannea coromandelica stem bark against phytopathogenic oomycete Aphanomyces cochlioides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2002; 50:6697-6703. [PMID: 12405764 DOI: 10.1021/jf020554g] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In a survey of nonhost plant secondary metabolites regulating motility and viability of zoospores of the Aphanomyces cochlioides, we found that stem bark extracts of Lannea coromandelica remarkably inhibited motility of zoospores followed by lysis. Bioassay-guided fractionation and chemical characterization of Lannea extracts by MALDI-TOF-MS revealed that the active constituents were angular type polyflavonoid tannins. Commercial polyflavonoid tannins, Quebracho and Mimosa, also showed identical zoosporicidal activity. Against zoospores, the motility-inhibiting and lytic activities were more pronounced in Lannea extracts (MIC 0.1 microg/mL) than in Quebracho (MIC 0.5 microg/mL) and Mimosa (MIC 0.5 microg/mL). Scanning electron microscopic observation visualized that both Lannea and commercial tannins caused lysis of cell membrane followed by fragmentation of cellular materials. Naturally occurring polyflavonoid tannin merits further study as potential zoospore regulating agent or as lead compound. To the best of our knowledge, this is the first report of zoosporicidal activity of natural polyflavonoid tannins against an oomycete phytopathogen.
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Affiliation(s)
- Md Tofazzal Islam
- Laboratory of Ecological Chemistry, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-Ku, Sapporo 060-8589, Japan
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