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Westrick NM, Smith DL, Kabbage M. Disarming the Host: Detoxification of Plant Defense Compounds During Fungal Necrotrophy. FRONTIERS IN PLANT SCIENCE 2021; 12:651716. [PMID: 33995447 PMCID: PMC8120277 DOI: 10.3389/fpls.2021.651716] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/26/2021] [Indexed: 05/02/2023]
Abstract
While fungal biotrophs are dependent on successfully suppressing/subverting host defenses during their interaction with live cells, necrotrophs, due to their lifestyle are often confronted with a suite of toxic metabolites. These include an assortment of plant defense compounds (PDCs) which can demonstrate broad antifungal activity. These PDCs can be either constitutively present in plant tissue or induced in response to infection, but are nevertheless an important obstacle which needs to be overcome for successful pathogenesis. Fungal necrotrophs have developed a number of strategies to achieve this goal, from the direct detoxification of these compounds through enzymatic catalysis and modification, to the active transport of various PDCs to achieve toxin sequestration and efflux. Studies have shown across multiple pathogens that the efficient detoxification of host PDCs is both critical for successful infection and often a determinant factor in pathogen host range. Here, we provide a broad and comparative overview of the various mechanisms for PDC detoxification which have been identified in both fungal necrotrophs and fungal pathogens which depend on detoxification during a necrotrophic phase of infection. Furthermore, the effect that these mechanisms have on fungal host range, metabolism, and disease control will be discussed.
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Xylosylated Detoxification of the Rice Flavonoid Phytoalexin Sakuranetin by the Rice Sheath Blight Fungus Rhizoctonia solani. Molecules 2018; 23:molecules23020276. [PMID: 29382171 PMCID: PMC6017487 DOI: 10.3390/molecules23020276] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/26/2018] [Accepted: 01/26/2018] [Indexed: 11/22/2022] Open
Abstract
Sakuranetin (1) is a rice flavanone-type phytoalexin. We have already reported that the metabolites from the detoxification of 1 by Pyriculariaoryzae are naringenin (2) and sternbin. In this study, we investigated whether the rice sheath blight fungus Rhizoctoniasolani, another major rice pathogen, can detoxify 1. The extract of R. solani suspension culture containing 1 was analyzed by LC-MS to identify the metabolites of 1. Three putative metabolites of 1 were detected in the extract from the R. solani suspension culture 12 h after the addition of 1, and they were identified as 2, sakuranetin-4′-O-β-d-xylopyranoside (3), and naringenin-7-O-β-d-xylopyranoside (4) by NMR, LC-MS/MS, and GC-MS analyses. The accumulation of 2, 3, and 4 reached their maximum levels 9–12 h after the addition of 1, whereas the content of 1 decreased to almost zero within 9 h. The antifungal activities of 3 and 4 against R. solani were negligible, and 2 showed weaker antifungal activity than 1. We concluded that 2, 3, and 4 are metabolites from the detoxification of 1 by R. solani. Xylosylation is a rare and efficient detoxification method for phytoalexins.
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Katsumata S, Hamana K, Horie K, Toshima H, Hasegawa M. Identification of Sternbin and Naringenin as Detoxified Metabolites from the Rice Flavanone Phytoalexin Sakuranetin by Pyricularia oryzae. Chem Biodivers 2017; 14. [PMID: 27647729 DOI: 10.1002/cbdv.201600240] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 09/16/2016] [Indexed: 01/21/2023]
Abstract
Sakuranetin (1) is a flavanone phytoalexin that has been reported to play an important role in disease resistance in rice plants. The rice blast fungus Pyricularia oryzae (syn. Magnaporthe oryzae) has been reported to metabolize 1 to lower its antifungal activity. Here, two flavanones, sternbin (2) and naringenin (3), were identified as metabolites of 1 in P. oryzae suspension culture by liquid chromatography tandem mass spectrometry (LC/MS/MS). The inhibition of 1, 2, and 3 on P. oryzae mycelial growth were 45%, 19%, and 19%, respectively, at a concentration of 100 μm. Thus, 2 and 3 are detoxified metabolites of 1 by P. oryzae.
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Affiliation(s)
- Shun Katsumata
- College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Ibaraki, 300-0393, Japan
| | - Kazuho Hamana
- College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Ibaraki, 300-0393, Japan
| | - Kiyotaka Horie
- United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan
| | - Hiroaki Toshima
- College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Ibaraki, 300-0393, Japan.,United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan
| | - Morifumi Hasegawa
- College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Ibaraki, 300-0393, Japan.,United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan
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Cho JG, Cha BJ, Min Lee S, Shrestha S, Jeong RH, Sung Lee D, Kim YC, Lee DG, Kang HC, Kim J, Baek NI. Diterpenes from the Roots ofOryza sativaL. and Their Inhibition Activity on NO Production in LPS-Stimulated RAW264.7 Macrophages. Chem Biodivers 2015; 12:1356-64. [DOI: 10.1002/cbdv.201400239] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Indexed: 11/09/2022]
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Horie K, Inoue Y, Sakai M, Yao Q, Tanimoto Y, Koga J, Toshima H, Hasegawa M. Identification of UV-Induced Diterpenes Including a New Diterpene Phytoalexin, Phytocassane F, from Rice Leaves by Complementary GC/MS and LC/MS Approaches. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:4050-4059. [PMID: 25865436 DOI: 10.1021/acs.jafc.5b00785] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Rice phytoalexins are regarded as one of the most important weapons against pathogenic microorganisms. We attempted to identify novel phytoalexins and their derivatives using GC/MS and LC/MS analyses. Diterpene derivatives, 9β-pimara-7,15-diene-3β,6β,19-triol, 1, stemar-13-en-2α-ol, 2, and 1α,2α-dihydroxy-ent-12,15-cassadiene-3,11-dione, 3, were isolated from UV-irradiated rice leaves by chromatographic methods. These structures were confirmed by 1D- and 2D-NMR and MS analyses. Interestingly, all three compounds were accumulated following an infection by the rice blast pathogen Magnaporthe oryzae. Compounds 1 and 2 exhibited weak antifungal activity and may be the biosynthetic intermediates of rice phytoalexins momilactones and oryzalexin S, respectively. Compound 3 exhibited relatively high inhibitory activity against the fungal mycelial growth of M. oryzae to the same extent as the known phytoalexin phytocassane A. We conclude that 3 is a member of the cassane-type phytoalexin family and propose the name phytocassane F.
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Affiliation(s)
- Kiyotaka Horie
- †United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Yasuno Inoue
- ‡College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Inashiki, Ibaraki 300-0393, Japan
| | - Miki Sakai
- ‡College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Inashiki, Ibaraki 300-0393, Japan
| | - Qun Yao
- ‡College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Inashiki, Ibaraki 300-0393, Japan
| | - Yosuke Tanimoto
- ‡College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Inashiki, Ibaraki 300-0393, Japan
| | - Jinichiro Koga
- §Department of Biosciences, Teikyo University, 1-1 Toyosatodai, Utsunomiya, Tochigi 320-8551, Japan
| | - Hiroaki Toshima
- †United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
- ‡College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Inashiki, Ibaraki 300-0393, Japan
| | - Morifumi Hasegawa
- †United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
- ‡College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Inashiki, Ibaraki 300-0393, Japan
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Analysis on blast fungus-responsive characters of a flavonoid phytoalexin sakuranetin; accumulation in infected rice leaves, antifungal activity and detoxification by fungus. Molecules 2014; 19:11404-18. [PMID: 25093982 PMCID: PMC6271790 DOI: 10.3390/molecules190811404] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 07/17/2014] [Accepted: 07/23/2014] [Indexed: 11/17/2022] Open
Abstract
To understand the role of the rice flavonoid phytoalexin (PA) sakuranetin for blast resistance, the fungus-responsive characteristics were studied. Young rice leaves in a resistant line exhibited hypersensitive reaction (HR) within 3 days post inoculation (dpi) of a spore suspension, and an increase in sakuranetin was detected at 3 dpi, increasing to 4-fold at 4 dpi. In the susceptible line, increased sakuranetin was detected at 4 dpi, but not at 3 dpi, by which a large fungus mass has accumulated without HR. Induced expression of a PA biosynthesis gene OsNOMT for naringenin 7-O-methyltransferase was found before accumulation of sakuranetin in both cultivars. The antifungal activity of sakuranetin was considerably higher than that of the major rice diterpenoid PA momilactone A in vitro and in vivo under similar experimental conditions. The decrease and detoxification of sakuranetin were detected in both solid and liquid mycelium cultures, and they took place slower than those of momilactone A. Estimated local concentration of sakuranetin at HR lesions was thought to be effective for fungus restriction, while that at enlarged lesions in susceptible rice was insufficient. These results indicate possible involvement of sakuranetin in blast resistance and its specific relation to blast fungus.
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