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Woo J, Jung S, Kim S, Li Y, Chung H, Roubtsova TV, Zhang H, Caseys C, Kliebenstein D, Kim KN, Bostock RM, Lee YH, Dickman MB, Choi D, Park E, Dinesh-Kumar SP. Attenuation of phytofungal pathogenicity of Ascomycota by autophagy modulators. Nat Commun 2024; 15:1621. [PMID: 38424448 PMCID: PMC10904834 DOI: 10.1038/s41467-024-45839-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 02/02/2024] [Indexed: 03/02/2024] Open
Abstract
Autophagy in eukaryotes functions to maintain homeostasis by degradation and recycling of long-lived and unwanted cellular materials. Autophagy plays important roles in pathogenicity of various fungal pathogens, suggesting that autophagy is a novel target for development of antifungal compounds. Here, we describe bioluminescence resonance energy transfer (BRET)-based high-throughput screening (HTS) strategy to identify compounds that inhibit fungal ATG4 cysteine protease-mediated cleavage of ATG8 that is critical for autophagosome formation. We identified ebselen (EB) and its analogs ebselen oxide (EO) and 2-(4-methylphenyl)-1,2-benzisothiazol-3(2H)-one (PT) as inhibitors of fungal pathogens Botrytis cinerea and Magnaporthe oryzae ATG4-mediated ATG8 processing. The EB and its analogs inhibit spore germination, hyphal development, and appressorium formation in Ascomycota pathogens, B. cinerea, M. oryzae, Sclerotinia sclerotiorum and Monilinia fructicola. Treatment with EB and its analogs significantly reduced fungal pathogenicity. Our findings provide molecular insights to develop the next generation of antifungal compounds by targeting autophagy in important fungal pathogens.
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Affiliation(s)
- Jongchan Woo
- Department of Plant Biology and the Genome Center, College of Biological Sciences, University of California, Davis, CA, USA
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie, WY, USA
- Plant Immunity Research Center, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Seungmee Jung
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie, WY, USA
| | - Seongbeom Kim
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Yurong Li
- Department of Plant Pathology and Microbiology, College of Agriculture and Life Sciences, Texas A & M University, College Station, TX, USA
- Corteva Agriscience, Johnston, IA, USA
| | - Hyunjung Chung
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Tatiana V Roubtsova
- Department of Plant Pathology, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA
| | - Honghong Zhang
- Department of Plant Pathology and Microbiology, College of Agriculture and Life Sciences, Texas A & M University, College Station, TX, USA
- Fujian University Key Laboratory for Plant-Microbe Interaction, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Celine Caseys
- Department of Plant Sciences, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA
| | - Dan Kliebenstein
- Department of Plant Sciences, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA
| | - Kyung-Nam Kim
- Department of Bioindustry and Bioresource Engineering, College of Life Sciences, Sejong University, Seoul, Republic of Korea
| | - Richard M Bostock
- Department of Plant Pathology, College of Agriculture and Environmental Sciences, University of California, Davis, CA, USA
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Martin B Dickman
- Department of Plant Pathology and Microbiology, College of Agriculture and Life Sciences, Texas A & M University, College Station, TX, USA
| | - Doil Choi
- Plant Immunity Research Center, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
| | - Eunsook Park
- Department of Molecular Biology, College of Agriculture, Life Sciences and Natural Resources, University of Wyoming, Laramie, WY, USA.
| | - Savithramma P Dinesh-Kumar
- Department of Plant Biology and the Genome Center, College of Biological Sciences, University of California, Davis, CA, USA.
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Olea AF, Rubio J, Sedan C, Carvajal D, Nuñez M, Espinoza L, Llovera L, Nuñez G, Taborga L, Carrasco H. Antifungal Activity of 2-Allylphenol Derivatives on the Botrytis cinerea Strain: Assessment of Possible Action Mechanism. Int J Mol Sci 2023; 24:ijms24076530. [PMID: 37047503 PMCID: PMC10095406 DOI: 10.3390/ijms24076530] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 03/24/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
Botrytis cinerea is a phytopathogenic fungus that causes serious damage to the agricultural industry by infecting various important crops. 2-allylphenol has been used in China as a fungicide for more than a decade, and it has been shown that is a respiration inhibitor. A series of derivatives of 2-allylphenol were synthesized and their activity against B. cinerea was evaluated by measuring mycelial growth inhibition. Results indicate that small changes in the chemical structure or the addition of substituent groups in the aromatic ring induce important variations in activity. For example, changing the hydroxyl group by methoxy or acetyl groups produces dramatic increases in mycelial growth inhibition, i.e., the IC50 value of 2-allylphenol decreases from 68 to 2 and 1 μg mL−1. In addition, it was found that the most active derivatives induce the inhibition of Bcaox expression in the early stages of B. cinerea conidia germination. This gene is associated with the activation of the alternative oxidase enzyme (AOX), which allows fungus respiration to continue in the presence of respiratory inhibitors. Thus, it seems that 2-allylphenol derivatives can inhibit the normal and alternative respiratory pathway of B. cinerea. Therefore, we believe that these compounds are a very attractive platform for the development of antifungal agents against B. cinerea.
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Gao W, Zhang C, Li B, Oh JS. Azoxystrobin exposure impairs meiotic maturation by disturbing spindle formation in mouse oocytes. Front Cell Dev Biol 2022; 10:1053654. [PMID: 36531942 PMCID: PMC9755494 DOI: 10.3389/fcell.2022.1053654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
Fungicides are a type of pesticide used to protect plants and crops from pathogenic fungi. Azoxystrobin (AZO), a natural methoxyacrylate derived from strobilurin, is one of the most widely used fungicides in agriculture. AZO exerts its fungicidal activity by inhibiting mitochondrial respiration, but its cytotoxicity to mammalian oocytes has not been studied. In this study, we investigated the effect of AZO exposure on mouse oocyte maturation to elucidate the underlying mechanisms of its possible reproductive toxicity. We found that AZO exposure disturbed meiotic maturation by impairing spindle formation and chromosome alignment, which was associated with decreased microtubule organizing center (MTOC) integrity. Moreover, AZO exposure induced abnormal mitochondrial distribution and increased oxidative stress. The AZO-induced toxicity to oocytes was relieved by melatonin supplementation during meiotic maturation. Therefore, our results suggest that AZO exposure impairs oocyte maturation not only by increasing oxidative stress and mitochondrial dysfunction, but also by decreasing MTOC integrity and subsequent spindle formation and chromosome alignment.
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Affiliation(s)
- Wen Gao
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Chen Zhang
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
- RNA Medicine Center, International Institutes of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Bichun Li
- College of Animal Science and Technology, Yangzhou University, Yangzhou, China
| | - Jeong Su Oh
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, South Korea
- Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, South Korea
- *Correspondence: Jeong Su Oh,
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Dong G, Zhang Y, Liang X, Wang M, Ye Q, Xian X, Yang Y. Resistance characterization of the natural population and resistance mechanism to pyraclostrobin in Lasiodiplodia theobromae. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 188:105232. [PMID: 36464332 DOI: 10.1016/j.pestbp.2022.105232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 06/17/2023]
Abstract
Lasiodiplodia theobromae is the main pathogen of mango stem-end rot disease, causing mango fruit decay and major economic loss. QoI resistance has been found in field populations of L. theobromae. The characterization and resistance mechanism of pyraclostrobin-resistant L. theobromae was investigated by using a combination of bioassays and biochemical and molecular methods. The pyraclostrobin resistance among the L. theobromae population samples from Hainan was 93.41%. The resistant isolates were stable after successive subculturing for 10 times on PDA. Cross-resistance was observed only between the Qols pyraclostrobin and azoxystrobin. The alternative oxidase (AOX) inhibitor SHAM notably decreased the EC50 values of pyraclostrobin for all tested L. theobromae isolates. Induction of AOX by pyraclostrobin was observed in mycelia cells of L. theobromae. After treatment with pyraclostrobin, the final ATP and AOX contents of all sensitive isolates were significantly lower than those of resistant isolates. The relevant mutation and high expression of the cytochrome b gene were not detected in resistant isolates. However, there were 4 mutations in the AOX gene, which were only observed in highly resistant isolates. Pretreatment with pyraclostrobin resulted in a significant upregulation of AOX gene expression, and the average expression level of the highly resistant isolates was 33-fold that of the control group. These results suggested that the AOX pathway is responsible for resistance to pyraclostrobin, and that the AOX-related resistance mechanism is common in field populations of L. theobromae in Hainan mango orchards.
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Affiliation(s)
- Guoran Dong
- College of Plant Protection, Hainan University, Haikou 570228, China
| | - Yu Zhang
- College of Plant Protection, Hainan University, Haikou 570228, China; Sanya Nanfan Research Institute of Hainan University, Sanya 572025, China
| | - Xioyu Liang
- College of Plant Protection, Hainan University, Haikou 570228, China; Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China
| | - Meng Wang
- College of Plant Protection, Hainan University, Haikou 570228, China; Sanya Nanfan Research Institute of Hainan University, Sanya 572025, China
| | - Qianqian Ye
- College of Plant Protection, Hainan University, Haikou 570228, China
| | - Xinwei Xian
- College of Plant Protection, Hainan University, Haikou 570228, China
| | - Ye Yang
- College of Plant Protection, Hainan University, Haikou 570228, China; Sanya Nanfan Research Institute of Hainan University, Sanya 572025, China.
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Synthesis and Antifungal Activity of New butenolide Containing Methoxyacrylate Scaffold. Molecules 2022; 27:molecules27196541. [PMID: 36235077 PMCID: PMC9573425 DOI: 10.3390/molecules27196541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/16/2022] Open
Abstract
In order to improve the antifungal activity of new butenolides containing oxime ether moiety, a series of new butenolide compounds containing methoxyacrylate scaffold were designed and synthesized, based on the previous reports. Their structures were characterized by 1H NMR, 13C NMR, HR-MS spectra, and X-ray diffraction analysis. The in vitro antifungal activities were evaluated by the mycelium growth rate method. The results showed that the inhibitory activities of these new compounds against Sclerotinia sclerotiorum were significantly improved, in comparison with that of the lead compound 3-8; the EC50 values of V-6 and VI-7 against S. sclerotiorum were 1.51 and 1.81 mg/L, nearly seven times that of 3-8 (EC50 10.62 mg/L). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation indicated that compound VI-3 had a significant impact on the structure and function of the hyphal cell of S. sclerotiorum mycelium and the positive control trifloxystrobin. Molecular simulation docking results indicated that the introduction of methoxyacrylate scaffold is beneficial to improving the antifungal activity of these compounds against S. sclerotiorum, which can be used as the lead for further structure optimization.
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Melo R, Armstrong V, Navarro F, Castro P, Mendoza L, Cotoras M. Characterization of the Fungitoxic Activity on Botrytis cinerea of N-phenyl-driman-9-carboxamides. J Fungi (Basel) 2021; 7:jof7110902. [PMID: 34829191 PMCID: PMC8623464 DOI: 10.3390/jof7110902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/22/2021] [Accepted: 10/22/2021] [Indexed: 11/16/2022] Open
Abstract
A total of 12 compounds were synthesized from the natural sesquiterpene (-) drimenol (compounds 4 to 15). The synthesized compounds corresponded to N-phenyl-driman-9-carboxamide derivatives, similar to some fungicides that inhibit the electron-transport chain. Their structures were characterized and confirmed by 1H NMR, 13C NMR spectroscopy, and mass spectrometry. Compounds 5 to 15 corresponded to novel compounds. The effect of the compounds on the mycelial growth of Botrytis cinerea was evaluated. Methoxylated and chlorinated compounds in the aromatic ring (compounds 6, 7, 12, and 13) exhibited the highest antifungal activity with IC50 values between 0.20 and 0.26 mM. On the other hand, the effect on conidial germination of B. cinerea of one methoxylated compound (6) and one chlorinated compound (7) was analyzed, and no inhibition was observed. Additionally, compound 7 decreased 36% the rate of oxygen consumption by germinating conidia.
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Affiliation(s)
- Ricardo Melo
- Núcleo de Química y Bioquímica, Facultad de Estudios Interdisciplinarios, Universidad Mayor, Santiago 8580745, Chile;
| | - Verónica Armstrong
- Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile;
| | - Freddy Navarro
- Laboratorio de Micología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 7820436, Chile; (F.N.); (P.C.)
| | - Paulo Castro
- Laboratorio de Micología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 7820436, Chile; (F.N.); (P.C.)
| | - Leonora Mendoza
- Laboratorio de Micología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 7820436, Chile; (F.N.); (P.C.)
- Correspondence: (L.M.); (M.C.)
| | - Milena Cotoras
- Laboratorio de Micología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 7820436, Chile; (F.N.); (P.C.)
- Correspondence: (L.M.); (M.C.)
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Wang W, Liu Y, Xue Z, Li J, Wang Z, Liu X. Activity of the Novel Fungicide SYP-34773 against Plant Pathogens and Its Mode of Action on Phytophthora infestans. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:11794-11803. [PMID: 34605240 DOI: 10.1021/acs.jafc.1c02679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
SYP-34773 is a pyrimidinamine derivative and a novel fungicide modified from diflumetorim. This study determined the antimicrobial spectrum of SYP-34773, which showed it could strongly inhibit the growth of some important plant pathogens including fungi and oomycetes. In particular, Phytophthora infestans is an oomycete sensitive to SYP-34773, and the mycelium growth stage was found to be the most sensitive stage, with an EC50 value of 0.2030 μg/mL. At a concentration of 200 μg/mL, SYP-34773 displayed an excellent control efficacy of 69.55% and 81.48% against potato and tomato blight disease caused by P. infestans under field conditions, respectively. Mode of action investigations showed that this fungicide could cause severe ultrastructure damage to the mycelia of P. infestans, inhibit its respiration, and increase the cell membrane permeability of this pathogen. The results of this study could provide useful information for the fungicide registration and application of SYP-34773 as a novel fungicide.
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Affiliation(s)
- Weizhen Wang
- China Agricultural University, Beijing 100193, People's Republic of China
| | - Ying Liu
- China Agricultural University, Beijing 100193, People's Republic of China
| | - Zhaolin Xue
- China Agricultural University, Beijing 100193, People's Republic of China
| | - Jingru Li
- China Agricultural University, Beijing 100193, People's Republic of China
| | - Zhiwen Wang
- China Agricultural University, Beijing 100193, People's Republic of China
| | - Xili Liu
- China Agricultural University, Beijing 100193, People's Republic of China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, People's Republic of China
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Matsuzaki Y, Uda Y, Kurahashi M, Iwahashi F. Microtiter plate test using liquid medium is an alternative method for monitoring metyltetraprole sensitivity in Cercospora beticola. PEST MANAGEMENT SCIENCE 2021; 77:1226-1234. [PMID: 33051963 PMCID: PMC7894156 DOI: 10.1002/ps.6133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/14/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Metyltetraprole is a new quinone outside inhibitor (QoI) fungicide showing potent activity against QoI-resistant fungi that possess the G143A cytochrome b mutation, which confers resistance to existing QoIs such as trifloxystrobin. For its sustainable use, monitoring of metyltetraprole sensitivity is necessary and the establishment of appropriate methodology is important in each pathogen species. RESULTS In Cercospora beticola, the causal agent of sugar beet leaf spot, some isolates were less sensitive to metyltetraprole (EC50 > 1 mg L-1 , higher than the saturated concentration) using the common agar plate method, even with 100 mg L-1 salicylhydroxamic acid, an alternative oxidase inhibitor. However, microtiter tests (EC50 < 0.01 mg L-1 ), conidial germination tests (EC50 < 0.01 mg L-1 ) and in planta tests (>80% control at 75 mg L-1 run-off spraying) confirmed that all tested isolates were highly sensitive to metyltetraprole. For trifloxystrobin, G143A mutants were clearly resistant upon microtiter plate tests (median EC50 > 2 mg L-1 ) and distinct from wild-type isolates (median EC50 < 0.01 mg L-1 ). Notably, mycelium fragments were usable for the microtiter plate tests and the test was applicable for isolates that do not form sufficient conidia. Our monitoring study by microtiter plate tests did not indicate the presence of metyltetraprole-resistant C. beticola isolates in populations in Hokkaido, Japan. CONCLUSION The microtiter tests were revealed to be useful for monitoring the sensitivity of C. beticola to metyltetraprole and trifloxystrobin. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Yuichi Matsuzaki
- Health and Crop Sciences Research LaboratorySumitomo Chemical Co., LtdTakarazukaJapan
| | - Yukie Uda
- Health and Crop Sciences Research LaboratorySumitomo Chemical Co., LtdTakarazukaJapan
| | - Makoto Kurahashi
- Makabe Experimental FarmSumitomo Chemical Co., LtdSakuragawaJapan
| | - Fukumatsu Iwahashi
- Health and Crop Sciences Research LaboratorySumitomo Chemical Co., LtdTakarazukaJapan
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Wang Y, Akhavan A, Hwang SF, Strelkov SE. Decreased Sensitivity of Leptosphaeria maculans to Pyraclostrobin in Alberta, Canada. PLANT DISEASE 2020; 104:2462-2468. [PMID: 32609053 DOI: 10.1094/pdis-11-19-2461-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Leptosphaeria maculans, the causal agent of blackleg of canola (Brassica napus), can be managed with pyraclostrobin and other strobilurin fungicides. Their frequent application, however, poses a risk for the development of insensitivity in fungal populations. A collection of L. maculans single-spore isolates recovered from infected canola stubble in Alberta, Canada, in 2016 was evaluated for its pyraclostrobin sensitivity. In conventional growth plate assays, the concentration of pyraclostrobin required to inhibit fungal growth by 50% (EC50) was determined to be 0.28 mg/liter in a subset of 38 isolates. This EC50 was four times greater than the mean EC50 (0.07 mg/liter) of baseline isolates collected in 2011. Two hundred sixty-three isolates were screened further with two discriminatory doses of 0.28 and 3.5 mg/liter of pyraclostrobin, resulting in growth inhibition values ranging from 16 to 82% and 41 to 100%, respectively. In microtiter plate assays with the same isolates, the mean EC50 was determined to be 0.0049 mg/liter, almost 3.3 times greater than the mean EC50 (0.0015 mg/liter) of the baseline isolates. The sensitivity of the isolates was also evaluated in microtiter plate assays with discriminatory doses of 0.006 and 0.075 mg/liter of pyraclostrobin, resulting in inhibition values ranging from 20 to 88% and 49 to 100%, respectively. This is the first report of isolates of L. maculans with increased insensitivity to pyraclostrobin in Canada, suggesting the need for improved fungicide stewardship.
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Affiliation(s)
- Yixiao Wang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Alireza Akhavan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Sheau-Fang Hwang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - Stephen E Strelkov
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
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Matsuzaki Y, Kiguchi S, Suemoto H, Iwahashi F. Antifungal activity of metyltetraprole against the existing QoI-resistant isolates of various plant pathogenic fungi: Metyltetraprole against QoI-R isolates. PEST MANAGEMENT SCIENCE 2020; 76:1743-1750. [PMID: 31769927 PMCID: PMC7204873 DOI: 10.1002/ps.5697] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/31/2019] [Accepted: 11/22/2019] [Indexed: 05/21/2023]
Abstract
BACKGROUND Metyltetraprole is a novel quinol oxidation site of Complex III inhibitor (QoI) fungicide that inhibits mitochondrial electron transport at the Qo site of the cytochrome bc1 complex. Previous reports have demonstrated that it is also active against the QoI-resistant (QoI-R) isolates of Zymoseptoria tritici and Pyrenophora teres with the mutations G143A and F129L in their cytochrome b gene, respectively. Further studies on cross-resistance between metyltetraprole and existing QoIs were performed using an increased number of isolates of Z. tritici, P. teres, Ramularia collo-cygni, Pyrenophora tritici-repentis, and several other plant pathogenic fungi. RESULTS Differences in the EC50 values between the wild-type and QoI-R isolates with the mutations G143A or F129L were always smaller for metyltetraprole compared to those for the existing QoIs, and they were never greater than five in terms of resistance factor. The 2-year field experiments showed that the metyltetraprole treatment did not increase the percentage of QoI-R isolates likely to harbor the G143A mutation in a Z. tritici population. CONCLUSION The unique behavior of metyltetraprole against the existing QoI-R isolates was confirmed for all tested pathogen species. Our results provide important information to establish a fungicide resistance management strategy using metyltetraprole in combination or alternation with other fungicides. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Yuichi Matsuzaki
- Health and Crop Sciences Research LaboratorySumitomo Chemical Co., Ltd.TakarazukaJapan
| | - So Kiguchi
- Health and Crop Sciences Research LaboratorySumitomo Chemical Co., Ltd.TakarazukaJapan
| | - Haruka Suemoto
- Health and Crop Sciences Research LaboratorySumitomo Chemical Co., Ltd.TakarazukaJapan
| | - Fukumatsu Iwahashi
- Health and Crop Sciences Research LaboratorySumitomo Chemical Co., Ltd.TakarazukaJapan
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Tian F, Lee SY, Woo SY, Chun HS. Alternative Oxidase: A Potential Target for Controlling Aflatoxin Contamination and Propagation of Aspergillus flavus. Front Microbiol 2020; 11:419. [PMID: 32256475 PMCID: PMC7092633 DOI: 10.3389/fmicb.2020.00419] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 02/27/2020] [Indexed: 12/16/2022] Open
Abstract
Aflatoxins are among the most hazardous natural cereal contaminants. These mycotoxins are produced by Aspergillus spp. as polyketide secondary metabolites. Aflatoxigenic fungi including A. flavus express the alternative oxidase (AOX), which introduces a branch in the cytochrome-based electron transfer chain by coupling ubiquinol oxidation directly with the reduction of O2 to H2O. AOX is closely associated with fungal pathogenesis, morphogenesis, stress signaling, and drug resistance and, as recently reported, affects the production of mycotoxins such as sterigmatocystin, the penultimate intermediate in aflatoxin B1 biosynthesis. Thus, AOX might be considered a target for controlling the propagation of and aflatoxin contamination by A. flavus. Hence, this review summarizes the current understanding of fungal AOX and the alternative respiration pathway and the development and potential applications of AOX inhibitors. This review indicates that AOX inhibitors, either alone or in combination with current antifungal agents, are potentially applicable for developing novel, effective antifungal strategies. However, considering the conservation of AOX in fungal and plant cells, a deeper understanding of fungal alternative respiration and fungal AOX structure is needed, along with effective fungal-specific AOX inhibitors.
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Affiliation(s)
- Fei Tian
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Sang Yoo Lee
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - So Young Woo
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Hyang Sook Chun
- Food Toxicology Laboratory, Advanced Food Safety Research Group, BK21 Plus, School of Food Science and Technology, Chung-Ang University, Anseong, South Korea
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Wang C, Guo L, Yao J, Wang A, Gao F, Zhao X, Zeng Z, Wang Y, Sun C, Cui H, Cui B. Preparation, characterization and antifungal activity of pyraclostrobin solid nanodispersion by self-emulsifying technique. PEST MANAGEMENT SCIENCE 2019; 75:2785-2793. [PMID: 30809936 DOI: 10.1002/ps.5390] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/14/2019] [Accepted: 02/22/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Pathogenic fungi are the causal agents of 70-80% of plant diseases. Therefore, it is imperative to explore new and high effective fungicides. Constructing nanoscale fungicides using nanomaterial and nanotechnology has attracted wide attention in recent years. RESULTS In this research, a pyraclostrobin solid nanodispersion (PSND) was prepared using the self-emulsifying method. The solid nanodispersion had a mean particle size of 20 nm and a zeta potential of -29.3 mV. The solubility and dissolution rate of the PSND increased owing to the decrease in particle size and the actions of the surfactants. The contact angle and retention volumes of the PSND on cucumber and cabbage leaf surfaces were greater than those of the commercial water dispersible granule. In addition, the median lethal concentration against Fusarium oxysporum was 0.7 43 µg mL-1 . The toxicity of the nanoparticles was 4.5 times that of the water dispersible granule (WDG). The high fungicidal activity of PSND promoted the production of excess reactive oxygen species (ROS). The activity levels of the antioxidant enzymes containing superoxide dismutase (SOD) and catalase (CAT) decreased in F. oxysporum. CONCLUSION The research introduced a new method for preparing insoluble pyraclostrobin solid nanoformulation for fungicides to enhance the fungicidal activity and reduce environmental pollution. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Chunxin Wang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Liang Guo
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Junwei Yao
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Anqi Wang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fei Gao
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiang Zhao
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhanghua Zeng
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yan Wang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Changjiao Sun
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Haixin Cui
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bo Cui
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
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13
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Barsottini MR, Pires BA, Vieira ML, Pereira JG, Costa PC, Sanitá J, Coradini A, Mello F, Marschalk C, Silva EM, Paschoal D, Figueira A, Rodrigues FH, Cordeiro AT, Miranda PC, Oliveira PS, Sforça ML, Carazzolle MF, Rocco SA, Pereira GA. Synthesis and testing of novel alternative oxidase (AOX) inhibitors with antifungal activity against Moniliophthora perniciosa (Stahel), the causal agent of witches' broom disease of cocoa, and other phytopathogens. PEST MANAGEMENT SCIENCE 2019; 75:1295-1303. [PMID: 30350447 DOI: 10.1002/ps.5243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/18/2018] [Accepted: 10/16/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Moniliophthora perniciosa (Stahel) Aime & Phillips-Mora is the causal agent of witches' broom disease (WBD) of cocoa (Theobroma cacao L.) and a threat to the chocolate industry. The membrane-bound enzyme alternative oxidase (AOX) is critical for M. perniciosa virulence and resistance to fungicides, which has also been observed in other phytopathogens. Notably AOX is an escape mechanism from strobilurins and other respiration inhibitors, making AOX a promising target for controlling WBD and other fungal diseases. RESULTS We present the first study aimed at developing novel fungal AOX inhibitors. N-Phenylbenzamide (NPD) derivatives were screened in the model yeast Pichia pastoris through oxygen consumption and growth measurements. The most promising AOX inhibitor (NPD 7j-41) was further characterized and displayed better activity than the classical AOX inhibitor SHAM in vitro against filamentous fugal phytopathogens, such as M. perniciosa, Sclerotinia sclerotiorum and Venturia pirina. We demonstrate that 7j-41 inhibits M. perniciosa spore germination and prevents WBD symptom appearance in infected plants. Finally, a structural model of P. pastoris AOX was created and used in ligand structure-activity relationships analyses. CONCLUSION We present novel fungal AOX inhibitors with antifungal activity against relevant phytopathogens. We envisage the development of novel antifungal agents to secure food production. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Mario Ro Barsottini
- Department of Genetics, Evolution, Microbiology and Imunology, Genomics and bioEnergy Laboratory, Institute of Biology, State University of Campinas, Campinas, Brazil
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Bárbara A Pires
- Department of Genetics, Evolution, Microbiology and Imunology, Genomics and bioEnergy Laboratory, Institute of Biology, State University of Campinas, Campinas, Brazil
| | - Maria L Vieira
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - José Gc Pereira
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Paulo Cs Costa
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
- Department of Organic Chemistry, Institute of Chemistry, State University of Campinas, Campinas, Brazil
| | - Jaqueline Sanitá
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Alessandro Coradini
- Department of Genetics, Evolution, Microbiology and Imunology, Genomics and bioEnergy Laboratory, Institute of Biology, State University of Campinas, Campinas, Brazil
| | - Fellipe Mello
- Department of Genetics, Evolution, Microbiology and Imunology, Genomics and bioEnergy Laboratory, Institute of Biology, State University of Campinas, Campinas, Brazil
| | - Cidnei Marschalk
- Department of Genetics, Evolution, Microbiology and Imunology, Genomics and bioEnergy Laboratory, Institute of Biology, State University of Campinas, Campinas, Brazil
| | - Eder M Silva
- Center for Nuclear Energy in Agriculture, University of Sao Paulo, Piracicaba, Brazil
| | - Daniele Paschoal
- Center for Nuclear Energy in Agriculture, University of Sao Paulo, Piracicaba, Brazil
| | - Antonio Figueira
- Center for Nuclear Energy in Agriculture, University of Sao Paulo, Piracicaba, Brazil
| | - Fábio Hs Rodrigues
- School of Life Sciences, University of Warwick - Gibbet Hill Campus, Coventry, United Kingdom
| | - Artur T Cordeiro
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Paulo Cml Miranda
- Department of Organic Chemistry, Institute of Chemistry, State University of Campinas, Campinas, Brazil
| | - Paulo Sl Oliveira
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Maurício L Sforça
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Marcelo F Carazzolle
- Department of Genetics, Evolution, Microbiology and Imunology, Genomics and bioEnergy Laboratory, Institute of Biology, State University of Campinas, Campinas, Brazil
| | - Silvana A Rocco
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Gonçalo Ag Pereira
- Department of Genetics, Evolution, Microbiology and Imunology, Genomics and bioEnergy Laboratory, Institute of Biology, State University of Campinas, Campinas, Brazil
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Baggio JS, Peres NA, Amorim L. Sensitivity of Botrytis cinerea Isolates from Conventional and Organic Strawberry Fields in Brazil to Azoxystrobin, Iprodione, Pyrimethanil, and Thiophanate-Methyl. PLANT DISEASE 2018; 102:1803-1810. [PMID: 30125196 DOI: 10.1094/pdis-08-17-1221-re] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Botrytis fruit rot, caused by Botrytis cinerea, is one of the most important strawberry diseases worldwide, and fungicide applications are often used to manage the disease in commercial production. Isolates of B. cinerea were collected from conventional and organic strawberry fields in four Brazilian States from 2013 to 2015 and their sensitivity to the main single-site mode-of action fungicides used in Brazil was tested. Resistance to azoxystrobin, iprodione, pyrimethanil, and thiophanate-methyl was found and values for effective concentration that inhibited mycelial growth by 50% were higher than 71.9, 1.2, 5.0, and 688 µg/ml, respectively, regardless the production system. Resistance to these fungicides was observed in 87.5, 76.6, 23.4, and 92.2% of isolates from conventional fields and 31.4, 22.9, 14.3, and 51.4% of isolates from organic fields, respectively. Moreover, frequencies of isolates with multiple fungicide resistance to the four active ingredients were 20.6 and 2.8% whereas 6.3 and 27.8% were sensitive to the four fungicides for conventional and organic areas, respectively. Molecular analyses of the cytochrome b, β-tubulin, and bos1 genes revealed the presence of G143A; E198A; and I365 N/S, Q369P, or N373S mutations, respectively, in resistant isolates of B. cinerea. Field rates of fungicides sprayed preventively to inoculated strawberry fruit failed to control disease caused by the respective resistant isolates.
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Affiliation(s)
- Juliana S Baggio
- Departamento de Fitopatologia, ESALQ, University of Sao Paulo, CEP 13418-900, Piracicaba, SP, Brazil
| | - Natalia A Peres
- Gulf Coast Research and Education Center, University of Florida, Wimauma
| | - Lilian Amorim
- Departmento de Fitopatologia, ESALQ, University of São Paulo, CEP 13418-900 Piracicaba, SP, Brazil
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15
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Preparation, characterization, and evaluation of azoxystrobin nanosuspension produced by wet media milling. APPLIED NANOSCIENCE 2018. [DOI: 10.1007/s13204-018-0745-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Abstract
To improve the bioavailability of the poorly water-soluble fungicide, an azoxystrobin nanosuspension was prepared by the wet media milling method. Due to their reduced mean particle size and polydispersity index, 1-Dodecanesulfonic acid sodium salt and polyvinylpyrrolidone K30 were selected from six conventional surfactants, the content only accounting for 15% of the active compound. The mean particle size, polydispersity index, and
$$\zeta$$
ζ
potential of the nanosuspension were determined to be 238.1 ± 1.5 nm, 0.17 ± 0.02 and − 31.8 ± 0.3 mV, respectively. The lyophilized nanosuspension mainly retained crystalline state, with only a little amorphous content as determined by powder X-ray diffraction. Compared to conventional fungicide formulations, the nanosuspension presented an increased retention volume and a reduced contact angle, indicating enhanced wettability and adhesion. In addition, the azoxystrobin nanosuspension showed the highest antifungal activity, with a medial lethal concentration of 1.4243 μg/mL against Fusarium oxysporum. In optical micrographs, hyphal deformations of thinner and intertwined hyphae were detected in the exposed group. Compared to the control group, the total soluble protein content, superoxide dismutase, and catalase activities were initially increased and then decreased with prolonged exposure time. The azoxystrobin nanosuspension reduced the defensive antioxidant capability of Fusarium oxysporum and resulted in the generation of excessive reactive oxygen species. This study provides a novel method for preparing nanosuspension formulation of poorly soluble antifungal agents to enhance the biological activity and decrease the negative environmental impact.
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16
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Young DH, Wang NX, Meyer ST, Avila‐Adame C. Characterization of the mechanism of action of the fungicide fenpicoxamid and its metabolite UK-2A. PEST MANAGEMENT SCIENCE 2018; 74:489-498. [PMID: 28960782 PMCID: PMC5813142 DOI: 10.1002/ps.4743] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 08/31/2017] [Accepted: 09/22/2017] [Indexed: 05/04/2023]
Abstract
BACKGROUND Fenpicoxamid is a new fungicide for control of Zymoseptoria tritici, and is a derivative of the natural product UK-2A. Its mode of action and target site interactions have been investigated. RESULTS UK-2A strongly inhibited cytochrome c reductase, whereas fenpicoxamid was much less active, consistent with UK-2A being the fungicidally active species generated from fenpicoxamid by metabolism. Both compounds caused rapid loss of mitochondrial membrane potential in Z. tritici spores. In Saccharomyces cerevisiae, amino acid substitutions N31K, G37C and L198F at the Qi quinone binding site of cytochrome b reduced sensitivity to fenpicoxamid, UK-2A and antimycin A. Activity of fenpicoxamid was not reduced by the G143A exchange responsible for strobilurin resistance. A docking pose for UK-2A at the Qi site overlaid that of antimycin A. Activity towards Botrytis cinerea was potentiated by salicylhydroxamic acid, showing an ability of alternative respiration to mitigate activity. Fungitoxicity assays against Z. tritici field isolates showed no cross-resistance to strobilurin, azole or benzimidazole fungicides. CONCLUSION Fenpicoxamid is a Qi inhibitor fungicide that provides a new mode of action for Z. tritici control. Mutational and modeling studies suggest that the active species UK-2A binds at the Qi site in a similar, but not identical, fashion to antimycin A. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
| | - Nick X Wang
- Dow AgroSciencesDiscovery ResearchIndianapolisINUSA
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17
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Gonzales JC, Brancini GT, Rodrigues GB, Silva-Junior GJ, Bachmann L, Wainwright M, Braga GÚ. Photodynamic inactivation of conidia of the fungus Colletotrichum abscissum on Citrus sinensis plants with methylene blue under solar radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 176:54-61. [DOI: 10.1016/j.jphotobiol.2017.09.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 08/11/2017] [Accepted: 09/11/2017] [Indexed: 02/06/2023]
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18
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Morales J, Mendoza L, Cotoras M. Alteration of oxidative phosphorylation as a possible mechanism of the antifungal action ofp-coumaric acid againstBotrytis cinerea. J Appl Microbiol 2017; 123:969-976. [DOI: 10.1111/jam.13540] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 06/06/2017] [Accepted: 06/28/2017] [Indexed: 11/28/2022]
Affiliation(s)
- J. Morales
- Facultad de Química y Biología; Universidad de Santiago de Chile; Santiago Chile
| | - L. Mendoza
- Facultad de Química y Biología; Universidad de Santiago de Chile; Santiago Chile
| | - M. Cotoras
- Facultad de Química y Biología; Universidad de Santiago de Chile; Santiago Chile
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19
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Nagashima H, Hirao A, Tokuda Y, Uruta K. Simultaneous Determination of Seven Kinds of Fungicides in Citrus Fruits by Gas Chromatograghy/Mass Spectrometry. Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) 2016; 57:101-6. [PMID: 27558228 DOI: 10.3358/shokueishi.57.101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A simple and accurate procedure was developed for the determination of seven fungicides, azoxystrobin (AZO), diphenyl (DP), fludioxonil (FLUDI), imazalil (IMZ), o-phenylphenol (OPP), pyrimethanil (PYRI) and thiabendazole (TBZ), in citrus fruits. The citrus fruit sample was extracted with acetonitrile and cleaned up with a graphite carbon/aminopropyl silanized silica gel solid-phase extraction cartridge using acetonitrile-toluene (3 : 1, v/v) as the eluent. Triphenylene was used as an internal standard (I.S.) at the concentration of 0.5 μg/mL. The sample solution was subjected to GC-MS utilizing the matrix-matched standard solution method. The recoveries of AZO, FLUDI, IMZ, OPP, PYRI and TBZ spiked in domestic citrus fruits (Satsuma mandarin) at the level of 0.01-10.0 μg/g were 72.8-104% and the limits of quantification were 0.01 μg/g. The recoveries of DP spiked in domestic citrus fruits at the level of 0.01-70.0 μg/g were 70.8-80.4% and the limit of quantification was 0.01 μg/g. The proposed method was applied to the determination of fungicides in citrus fruits purchased in various markets.
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20
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Abstract
Philasterides dicentrarchi causes a severe disease in turbot, and at present there are no drugs available to treat infected fish. We have previously demonstrated that, in addition to the classical respiratory pathway, P. dicentrarchi possesses an alternative mitochondrial respiratory pathway that is cyanide-insensitive and salicylhydroxamic acid (SHAM)-sensitive. In this study, we found that during the initial phase of growth in normoxia, ciliate respiration is sensitive to the natural polyphenol resveratrol (RESV) and to Antimycin A (AMA). However, under hypoxic conditions, the parasite utilizes AMA-insensitive respiration, which is completely inhibited by RESV and by the antioxidant propyl gallate (PG), an alternative oxidase (AOX) inhibitor. PG caused significantly dose-dependent inhibition of the in vitro growth of the parasite under normoxia and hypoxia and an over-expression of heat shock proteins of the Hsp70 subfamily. RESV and PG may affect the protective role of the AOX against mitochondrial oxidative stress, leading to an impaired mitochondrial membrane potential and mitochondrial dysfunction, which the parasite attempts to neutralize by increasing the expression of Hsp70. In view of the antiparasitic effects induced by AOX inhibitors and the absence of AOX in their host, this enzyme constitutes a potential target for the development of new drugs against scuticociliatosis.
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21
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Kunova A, Pizzatti C, Bonaldi M, Cortesi P. Sensitivity of Nonexposed and Exposed Populations of Magnaporthe oryzae from Rice to Tricyclazole and Azoxystrobin. PLANT DISEASE 2014; 98:512-518. [PMID: 30708720 DOI: 10.1094/pdis-04-13-0432-re] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Magnaporthe oryzae is the major pathogen of cultivated rice worldwide, which can cause substantial losses to rice production. Rice blast management is based predominantly on the application of fungicides; however, only a little is known about responses of pathogen populations to the most widely used fungicides. In this work, the baseline sensitivity of the Italian M. oryzae population to tricyclazole and azoxystrobin in terms of mycelium growth was determined, and the possible adaptation of the pathogen population after several years of repeated exposure to fungicide treatments was evaluated. All the analyzed strains demonstrated higher sensitivity and variability to azoxystrobin (concentration of fungicide causing 50% growth inhibition [ED50] = 0.063 mg liter-1) than to tricyclazole (99.289 mg liter-1). After comparing two additional populations collected from fields repeatedly treated with fungicides to the baseline, no decrease in sensitivity toward these fungicides was observed and no resistant strains were detected. The shift of the pathogen sensitivity toward these fungicides has not occurred, although we observed slightly increased variance associated with ED50 of azoxystrobin. Therefore, both azoxystrobin and tricyclazole can be used to manage rice blast in Italy but it will be important to continue monitoring M. oryzae population to early detect possible azoxystrobin resistance.
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Affiliation(s)
- Andrea Kunova
- Università degli Studi di Milano, Department of Food, Environmental and Nutritional Sciences, 20133 Milano, Italy
| | - Cristina Pizzatti
- Università degli Studi di Milano, Department of Food, Environmental and Nutritional Sciences, 20133 Milano, Italy
| | - Maria Bonaldi
- Università degli Studi di Milano, Department of Food, Environmental and Nutritional Sciences, 20133 Milano, Italy
| | - Paolo Cortesi
- Università degli Studi di Milano, Department of Food, Environmental and Nutritional Sciences, 20133 Milano, Italy
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22
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Kim JH, Mahoney N, Chan KL, Campbell BC, Haff RP, Stanker LH. Use of benzo analogs to enhance antimycotic activity of kresoxim methyl for control of aflatoxigenic fungal pathogens. Front Microbiol 2014; 5:87. [PMID: 24639673 PMCID: PMC3945611 DOI: 10.3389/fmicb.2014.00087] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 02/18/2014] [Indexed: 01/27/2023] Open
Abstract
The aim of this study was to examine two benzo analogs, octylgallate (OG) and veratraldehyde (VT), as antifungal agents against strains of Aspergillus parasiticus and A.flavus (toxigenic or atoxigenic). Both toxigenic and atoxigenic strains used were capable of producing kojic acid, another cellular secondary product. A. fumigatus was used as a genetic model for this study. When applied independently, OG exhibits considerably higher antifungal activity compared to VT. The minimum inhibitory concentrations (MICs) of OG were 0.3–0.5 mM, while that of VT were 3.0–5.0 mM in agar plate-bioassays. OG or VT in concert with the fungicide kresoxim methyl (Kre-Me; strobilurin) greatly enhanced sensitivity of Aspergillus strains to Kre-Me. The combination with OG also overcame the tolerance of A. fumigatus mitogen-activated protein kinase (MAPK) mutants to Kre-Me. The degree of compound interaction resulting from chemosensitization of the fungi by OG was determined using checkerboard bioassays, where synergistic activity greatly lowered MICs or minimum fungicidal concentrations. However, the control chemosensitizer benzohydroxamic acid, an alternative oxidase inhibitor conventionally applied in concert with strobilurin, did not achieve synergism. The level of antifungal or chemosensitizing activity was also “compound—strain” specific, indicating differential susceptibility of tested strains to OG or VT, and/or heat stress. Besides targeting the antioxidant system, OG also negatively affected the cell wall-integrity pathway, as determined by the inhibition of Saccharomyces cerevisiae cell wall-integrity MAPK pathway mutants. We concluded that certain benzo analogs effectively inhibit fungal growth. They possess chemosensitizing capability to increase efficacy of Kre-Me and thus, could reduce effective dosages of strobilurins and alleviate negative side effects associated with current antifungal practices. OG also exhibits moderate antiaflatoxigenic activity.
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Affiliation(s)
- Jong H Kim
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Noreen Mahoney
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Kathleen L Chan
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Bruce C Campbell
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Ronald P Haff
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
| | - Larry H Stanker
- Foodborne Toxin Detection and Prevention Research Unit, Western Regional Research Center, USDA-ARS Albany, CA, USA
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23
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Alejo JL, Blanchard SC, Andersen OS. Small-molecule photostabilizing agents are modifiers of lipid bilayer properties. Biophys J 2014; 104:2410-8. [PMID: 23746513 DOI: 10.1016/j.bpj.2013.04.039] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 04/09/2013] [Accepted: 04/11/2013] [Indexed: 10/26/2022] Open
Abstract
Small-molecule photostabilizing or protective agents (PAs) provide essential support for the stability demands on fluorescent dyes in single-molecule spectroscopy and fluorescence microscopy. These agents are employed also in studies of cell membranes and model systems mimicking lipid bilayer environments, but there is little information about their possible effects on membrane structure and physical properties. Given the impact of amphipathic small molecules on bilayer properties such as elasticity and intrinsic curvature, we investigated the effects of six commonly used PAs--cyclooctatetraene (COT), para-nitrobenzyl alcohol (NBA), Trolox (TX), 1,4-diazabicyclo[2.2.2]octane (DABCO), para-nitrobenzoic acid (pNBA), and n-propyl gallate (nPG)--on bilayer properties using a gramicidin A (gA)-based fluorescence quench assay to probe for PA-induced changes in the gramicidin monomer↔dimer equilibrium. The experiments were done using fluorophore-loaded large unilamellar vesicles that had been doped with gA, and changes in the gA monomer↔dimer equilibrium were assayed using a gA channel-permeable fluorescence quencher (Tl⁺). Changes in bilayer properties caused by, e.g., PA adsorption at the bilayer/solution interface that alter the equilibrium constant for gA channel formation, and thus the number of conducting gA channels in the large unilamellar vesicle membrane, will be detectable as changes in the rate of Tl⁺ influx-the fluorescence quench rate. Over the experimentally relevant millimolar concentration range, TX, NBA, and pNBA, caused comparable increases in gA channel activity. COT, also in the millimolar range, caused a slight decrease in gA channel activity. nPG increased channel activity at submillimolar concentrations. DABCO did not alter gA activity. Five of the six tested PAs thus alter lipid bilayer properties at experimentally relevant concentrations, which becomes important for the design and analysis of fluorescence studies in cells and model membrane systems. We therefore tested combinations of COT, NBA, and TX; the combinations altered the fluorescence quench rate less than would be predicted assuming their effects on bilayer properties were additive. The combination of equimolar concentrations of COT and NBA caused minimal changes in the fluorescence quench rate.
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Affiliation(s)
- Jose L Alejo
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
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Genetic and functional investigation of Zn(2)Cys(6) transcription factors RSE2 and RSE3 in Podospora anserina. EUKARYOTIC CELL 2013; 13:53-65. [PMID: 24186951 DOI: 10.1128/ec.00172-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In Podospora anserina, the two zinc cluster proteins RSE2 and RSE3 are essential for the expression of the gene encoding the alternative oxidase (aox) when the mitochondrial electron transport chain is impaired. In parallel, they activated the expression of gluconeogenic genes encoding phosphoenolpyruvate carboxykinase (pck) and fructose-1,6-biphosphatase (fbp). Orthologues of these transcription factors are present in a wide range of filamentous fungi, and no other role than the regulation of these three genes has been evidenced so far. In order to better understand the function and the organization of RSE2 and RSE3, we conducted a saturated genetic screen based on the constitutive expression of the aox gene. We identified 10 independent mutations in 9 positions in rse2 and 11 mutations in 5 positions in rse3. Deletions were generated at some of these positions and the effects analyzed. This analysis suggests the presence of central regulatory domains and a C-terminal activation domain in both proteins. Microarray analysis revealed 598 genes that were differentially expressed in the strains containing gain- or loss-of-function mutations in rse2 or rse3. It showed that in addition to aox, fbp, and pck, RSE2 and RSE3 regulate the expression of genes encoding the alternative NADH dehydrogenase, a Zn2Cys6 transcription factor, a flavohemoglobin, and various hydrolases. As a complement to expression data, a metabolome profiling approach revealed that both an rse2 gain-of-function mutation and growth on antimycin result in similar metabolic alterations in amino acids, fatty acids, and α-ketoglutarate pools.
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Kim JH, Haff RP, Faria NCG, Martins MDL, Chan KL, Campbell BC. Targeting the mitochondrial respiratory chain of Cryptococcus through antifungal chemosensitization: a model for control of non-fermentative pathogens. Molecules 2013; 18:8873-94. [PMID: 23892633 PMCID: PMC6270351 DOI: 10.3390/molecules18088873] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 11/16/2022] Open
Abstract
Enhanced control of species of Cryptococcus, non-fermentative yeast pathogens, was achieved by chemosensitization through co-application of certain compounds with a conventional antimicrobial drug. The species of Cryptococcus tested showed higher sensitivity to mitochondrial respiratory chain (MRC) inhibition compared to species of Candida. This higher sensitivity results from the inability of Cryptococcus to generate cellular energy through fermentation. To heighten disruption of cellular MRC, octyl gallate (OG) or 2,3-dihydroxybenzaldehyde (2,3-DHBA), phenolic compounds inhibiting mitochondrial functions, were selected as chemosensitizers to pyraclostrobin (PCS; an inhibitor of complex III of MRC). The cryptococci were more susceptible to the chemosensitization (i.e., PCS + OG or 2,3-DHBA) than the Candida with all Cryptococcus strains tested being sensitive to this chemosensitization. Alternatively, only few of the Candida strains showed sensitivity. OG possessed higher chemosensitizing potency than 2,3-DHBA, where the concentration of OG required with the drug to achieve chemosensitizing synergism was much lower than that required of 2,3-DHBA. Bioassays with gene deletion mutants of the model yeast Saccharomyces cerevisiae showed that OG or 2,3-DHBA affect different cellular targets. These assays revealed mitochondrial superoxide dismutase or glutathione homeostasis plays a relatively greater role in fungal tolerance to 2,3-DHBA or OG, respectively. These findings show that application of chemosensitizing compounds that augment MRC debilitation is a promising strategy to antifungal control against yeast pathogens.
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Affiliation(s)
- Jong H. Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan St., Albany, CA 94710, USA; E-Mails: (R.P.H.); (K.L.C.); (B.C.C.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-510-559-5841; Fax: +1-510-559-5737
| | - Ronald P. Haff
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan St., Albany, CA 94710, USA; E-Mails: (R.P.H.); (K.L.C.); (B.C.C.)
| | - Natália C. G. Faria
- Instituto de Higiene e Medicina Tropical/CREM, Universidade Nova de Lisboa, Portugal; E-Mails: (N.C.G.F.); (M.L.M.)
| | - Maria de L. Martins
- Instituto de Higiene e Medicina Tropical/CREM, Universidade Nova de Lisboa, Portugal; E-Mails: (N.C.G.F.); (M.L.M.)
| | - Kathleen L. Chan
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan St., Albany, CA 94710, USA; E-Mails: (R.P.H.); (K.L.C.); (B.C.C.)
| | - Bruce C. Campbell
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan St., Albany, CA 94710, USA; E-Mails: (R.P.H.); (K.L.C.); (B.C.C.)
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Kim JH, Campbell BC, Chan KL, Mahoney N, Haff RP. Synergism of antifungal activity between mitochondrial respiration inhibitors and kojic acid. Molecules 2013; 18:1564-81. [PMID: 23353126 PMCID: PMC6269749 DOI: 10.3390/molecules18021564] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 01/19/2013] [Accepted: 01/22/2013] [Indexed: 11/17/2022] Open
Abstract
Co-application of certain types of compounds to conventional antimicrobial drugs can enhance the efficacy of the drugs through a process termed chemosensitization. We show that kojic acid (KA), a natural pyrone, is a potent chemosensitizing agent of complex III inhibitors disrupting the mitochondrial respiratory chain in fungi. Addition of KA greatly lowered the minimum inhibitory concentrations of complex III inhibitors tested against certain filamentous fungi. Efficacy of KA synergism in decreasing order was pyraclostrobin > kresoxim-methyl > antimycin A. KA was also found to be a chemosensitizer of cells to hydrogen peroxide (H2O2), tested as a mimic of reactive oxygen species involved in host defense during infection, against several human fungal pathogens and Penicillium strains infecting crops. In comparison, KA-mediated chemosensitization to complex III inhibitors/H2O2 was undetectable in other types of fungi, including Aspergillus flavus, A. parasiticus, and P. griseofulvum, among others. Of note, KA was found to function as an antioxidant, but not as an antifungal chemosensitizer in yeasts. In summary, KA could serve as an antifungal chemosensitizer to complex III inhibitors or H2O2 against selected human pathogens or Penicillium species. KA-mediated chemosensitization to H2O2 seemed specific for filamentous fungi. Thus, results indicate strain- and/or drug-specificity exist during KA chemosensitization.
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Affiliation(s)
- Jong H Kim
- Plant Mycotoxin Research Unit, Western Regional Research Center, USDA-ARS, 800 Buchanan St., Albany, CA 94710, USA.
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Zhang X, Gao YX, Liu HJ, Guo BY, Wang HL. Design, Synthesis and Antifungal Activities of Novel Strobilurin Derivatives Containing Pyrimidine Moieties. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.8.2627] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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