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Achilonu CC, Gryzenhout M, Ghosh S, Marais GJ. In Vitro Evaluation of Azoxystrobin, Boscalid, Fentin-Hydroxide, Propiconazole, Pyraclostrobin Fungicides against Alternaria alternata Pathogen Isolated from Carya illinoinensis in South Africa. Microorganisms 2023; 11:1691. [PMID: 37512864 PMCID: PMC10384428 DOI: 10.3390/microorganisms11071691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/17/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
Black spot disease or Alternaria black spot (ABS) of pecan (Carya illinoinensis) in South Africa is caused by Alternaria alternata. This fungal pathogen impedes the development of pecan trees and leads to low yield in pecan nut production. The present study investigated the in vitro effect of six fungicides against the mycelial growth of A. alternata isolates from ABS symptoms. Fungicides tested include Tilt (propiconazole), Ortiva (azoxystrobin), AgTin (fentin hydroxide), and Bellis (boscalid + pyraclostrobin). All fungicides were applied in 3 concentrations (0.2, 1, and 5 μg mL-1). Tilt and Bumper 250 EC containing propiconazole active ingredient (demethylation Inhibitors) were the most effective and inhibited all mycelial growth from up to 6 days post-incubation. The other active ingredients (succinate dehydrogenase inhibitors, organotin compounds, and quinone outside inhibitors) showed 75-85% mycelial growth inhibition. The effective concentration to inhibit mycelial growth by 50% (EC50) was estimated for each isolate and fungicide. The overall mean EC50 values for each fungicide on the six isolates were 1.90 μg mL-1 (Tilt), 1.86 μg mL-1 (Ortiva), 1.53 μg mL-1 (AgTin), and 1.57 μg mL-1 for (Bellis). This initial screening suggested that propiconazole fungicide was the most effective for future field trials test and how these fungicides could be used in controlling ABS disease.
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Affiliation(s)
- Conrad Chibunna Achilonu
- Department of Plant Sciences, Division of Plant Pathology, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9300, Free State, South Africa
| | - Marieka Gryzenhout
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9300, Free State, South Africa
| | - Soumya Ghosh
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9300, Free State, South Africa
| | - Gert Johannes Marais
- Department of Plant Sciences, Division of Plant Pathology, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9300, Free State, South Africa
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Achilonu CC, Marais GJ, Ghosh S, Gryzenhout M. Multigene Phylogeny and Pathogenicity Trials Revealed Alternaria alternata as the Causal Agent of Black Spot Disease and Seedling Wilt of Pecan ( Carya illinoinensis) in South Africa. Pathogens 2023; 12:pathogens12050672. [PMID: 37242342 DOI: 10.3390/pathogens12050672] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/13/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
The pecan (Carya illinoinensis) industry in South Africa is growing rapidly, and it is becoming increasingly crucial to understand the risks posed to pecans by fungal pathogens. Black spots on leaves, shoots, and nuts in shucks caused by Alternaria species have been observed since 2014 in the Hartswater region of the Northern Cape Province of South Africa. Species of Alternaria include some of the most ubiquitous plant pathogens on earth. The aim of this study was to use molecular techniques to identify the causative agents of Alternaria black spot and seedling wilt isolated from major South African pecan-production areas. Symptomatic and non-symptomatic pecan plant organs (leaves, shoots, and nuts-in-shucks) were collected from pecan orchards, representing the six major production regions in South Africa. Thirty Alternaria isolates were retrieved from the sampled tissues using Potato Dextrose Agar (PDA) culture media and molecular identification was conducted. The phylogeny of multi-locus DNA sequences of Gapdh, Rpb2, Tef1, and Alt a 1 genes revealed that the isolates were all members of Alternaria alternata sensu stricto, forming part of the Alternaria alternata species complex. The virulence of six A. alternata isolates were tested on detached nuts of Wichita and Ukulinga cultivars, respectively, as well as detached leaves of Wichita. The A. alternata isolates were also evaluated for their ability to cause seedling wilt in Wichita. The results differed significantly between wounded and unwounded nuts of both cultivars, but not between the cultivars. Similarly, the disease lesions on the wounded detached leaves were significantly different in size from the unwounded leaves. The seedling tests confirmed that A. alternata is pathogenic and that A. alternata causes black spot disease and seedling wilt of pecans. This study is one of the first documentations of Alternaria black spot disease of pecan trees and its widespread occurrence in South Africa.
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Affiliation(s)
- Conrad Chibunna Achilonu
- Department of Plant Sciences, Division of Plant Pathology, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9300, Free State, South Africa
| | - Gert Johannes Marais
- Department of Plant Sciences, Division of Plant Pathology, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9300, Free State, South Africa
| | - Soumya Ghosh
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9300, Free State, South Africa
| | - Marieka Gryzenhout
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein 9300, Free State, South Africa
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Li J, Zheng H. Coverage of HPV-Related Information on Chinese Social Media: a Content Analysis of Articles in Zhihu. Hum Vaccin Immunother 2020; 16:2548-2554. [PMID: 32159420 PMCID: PMC7644171 DOI: 10.1080/21645515.2020.1729028] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/08/2020] [Indexed: 10/24/2022] Open
Abstract
Information about human papillomavirus (HPV) disease and its vaccination has been increasingly communicated and discussed on social media platforms. The current study aims to investigate the coverage of HPV-related information on one of the most popular Chinese social media - Zhihu. Data for this study were user-generated articles, which were identified and collected by a Python web crawler with keyword searching. The final sample included a total of 115 articles, covering a two-year period between 2017 and 2018. Each article was coded for several key characteristics, including HPV epidemiological information, health belief model (HBM) constructs, framing strategy, and responses to the article. Results suggested that most of the articles reported HPV's relationship to cervical cancer, HPV severity, and vaccination benefits. Thematic framing was more often used by the Zhihu articles to disseminate HPV-related issues, and a significant relationship between framing strategy and information coverage was found. The study has not only theoretically extended the literature of online HPV vaccine information coverage, but also practically suggested the needs to communicate comprehensive and detailed knowledge about HPV vaccination on Chinese social media.
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Affiliation(s)
- Jinhui Li
- School of Journalism and Communication, Jinan University, Guangdong, China
- Media National Experimental Teaching Demonstration Center, Jinan University, Guangdong, China
| | - Han Zheng
- Wee Kim Wee School of Communication and Information, Nanyang Technological University, Singapore
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Cai ZY, Liu YX, Shi YP, Dai LM, Li LL, Mu HJ, Lv ML, Liu XY. Alternaria yunnanensis sp. nov., a New Alternaria Species Causing Foliage Spot of Rubber Tree in China. Mycobiology 2019; 47:66-75. [PMID: 30988991 PMCID: PMC6450485 DOI: 10.1080/12298093.2019.1575584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 11/21/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
A new species of Alternaria causing leaf spots on the rubber tree (Hevea brasiliensis) in Yunnan, China, was isolated, examined, and illustrated. Morphologically, it belongs to the section Porri of Alternaria, which produces relatively large conidia and a simple or branched, filamentous long beak. It is, however, characterized by conidiophores gradually enlarging near the apex into a clavate conidiogenous cell and long ellipsoid to obclavate, smooth-walled conidia with a long filamentous beak. Molecular phylogenetic analyses based on ITS rDNA, GAPDH, and TEF1-alpha sequences demonstrate that the phytopathogen falls in the clade of the section Porri, being most closely related to A. sidae, A. sennae, A. deseriticola, A. cyamopsidis, A. rostellata, A. nitrimali, A. crassa, and A. thunbergiae.
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Affiliation(s)
- Zhi-Ying Cai
- Research Centre of Plant Protection, Yunnan Institute of Tropical Crops, Jinghong, 666100, China
| | - Yi-Xian Liu
- Research Centre of Plant Protection, Yunnan Institute of Tropical Crops, Jinghong, 666100, China
| | - Yu-Ping Shi
- Research Centre of Plant Protection, Yunnan Institute of Tropical Crops, Jinghong, 666100, China
| | - Li-Ming Dai
- Research Centre of Plant Protection, Yunnan Institute of Tropical Crops, Jinghong, 666100, China
| | - Lan-Lan Li
- Research Centre of Plant Protection, Yunnan Institute of Tropical Crops, Jinghong, 666100, China
| | - Hong-Jun Mu
- Research Centre of Plant Protection, Yunnan Institute of Tropical Crops, Jinghong, 666100, China
| | - Mei-Lin Lv
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiao-yong Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
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Chen Y, Cai G, Zhang C, Yao J, Wang Z, Wang Z, Hu C, Lv H, Li L, Zhou B. The association of serum markers of fibrosis and development of liver cirrhosis in chronic hepatitis B patients: A systematic review and meta-analysis. Cogent Medicine 2019. [DOI: 10.1080/2331205x.2019.1619896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- Yongdi Chen
- Department of Scientific Research and Information Management, Zhejiang Provincial Center for Disease Control and Prevention, , 3399 Binsheng Road, Hangzhou 310051, China
| | - Gaofeng Cai
- Department of Scientific Research and Information Management, Zhejiang Provincial Center for Disease Control and Prevention, , 3399 Binsheng Road, Hangzhou 310051, China
| | - Chu Zhang
- College of Humanities and Management, Zhejiang Chinese Medical University, Hangzhou 310051, China
| | - Jun Yao
- Department of Immunization planning, Zhejiang Provincial Center for Disease Control and Prevention, 3399 Binsheng Road, Hangzhou 310051, China
| | - Zhengting Wang
- Department of Scientific Research and Information Management, Zhejiang Provincial Center for Disease Control and Prevention, , 3399 Binsheng Road, Hangzhou 310051, China
| | - Zhifang Wang
- Department of Environmental Health, Zhejiang Provincial Center for Disease Control and Prevention, 3399 Binsheng Road, Hangzhou 310051, China
| | - Chonggao Hu
- Zhejiang Provincial Center for Disease Control and Prevention, 3399 Binsheng Road, Hangzhou 310051, China
| | - Huakun Lv
- Department of Immunization planning, Department of Zhejiang provincial key laboratory of infectious disease vaccine and prevention and control, Zhejiang Provincial Center for Disease Control and Prevention, 3399 Binsheng Road, Hangzhou 310051, China
| | - Li Li
- Department of Scientific Research and Information Management, Zhejiang Provincial Center for Disease Control and Prevention, , 3399 Binsheng Road, Hangzhou 310051, China
| | - Biao Zhou
- Department of Scientific Research and Information Management, Zhejiang Provincial Center for Disease Control and Prevention, , 3399 Binsheng Road, Hangzhou 310051, China
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Kosawang C, Amby DB, Bussaban B, McKinney LV, Xu J, Kjær ED, Collinge DB, Nielsen LR. Fungal communities associated with species of Fraxinus tolerant to ash dieback, and their potential for biological control. Fungal Biol 2017; 122:110-120. [PMID: 29458714 DOI: 10.1016/j.funbio.2017.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 12/11/2022]
Abstract
Ash dieback, caused by the fungus Hymenoscyphus fraxineus, has threatened ash trees in Europe for more than two decades. However, little is known of how endophytic communities affect the pathogen, and no effective disease management tools are available. While European ash (Fraxinus excelsior) is severely affected by the disease, other more distantly related ash species do not seem to be affected. We hypothesise that fungal endophytic communities of tolerant ash species can protect the species against ash dieback, and that selected endophytes have potential as biocontrol agents. These hypotheses were tested by isolating members of the fungal communities of five tolerant ash species, and identifying them using ITS regions. Candidate endophytes were tested by an in vitro antagonistic assay with H.fraxineus. From a total of 196 isolates we identified 9 fungal orders, 15 families, and 40 species. Fungi in orders Pleosporales, such as Boeremia exigua and Diaporthe spp., and Hypocreales (e.g., Fusarium sp.), were recovered in most communities, suggesting they are common taxa. The in vitro antagonistic assay revealed five species with high antagonistic activity against H. fraxineus. These endophytes were identified based on ITS region as Sclerostagonospora sp., Setomelanomma holmii, Epicoccum nigrum, B. exigua and Fusarium sp. Three of these taxa have been described previously as antagonists of plant pathogenic microbes, and are of interest for future studies of their potential as biological control agents against ash dieback, especially for valuable ash trees in parks and urban areas.
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Affiliation(s)
- Chatchai Kosawang
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark.
| | - Daniel Buchvaldt Amby
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark; Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Denmark
| | - Boonsom Bussaban
- Department of Biology, Faculty of Science, Chiang Mai University, Thailand; Center of Excellence in Bioresources for Agriculture, Industry and Medicine, Faculty of Science, Chiang Mai University, Thailand
| | - Lea Vig McKinney
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Jing Xu
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - Erik D Kjær
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
| | - David B Collinge
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Denmark
| | - Lene Rostgaard Nielsen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
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