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Yang G, Cui S, Huang W, Wang S, Ma J, Zhang Y, Xu J. Greenhouses represent an important evolutionary niche for Alternaria alternata. Microbiol Spectr 2024; 12:e0039024. [PMID: 38727239 DOI: 10.1128/spectrum.00390-24] [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: 02/12/2024] [Accepted: 04/03/2024] [Indexed: 06/06/2024] Open
Abstract
Alternaria alternata is a ubiquitous soil-borne fungus capable of causing diseases in a variety of plants and occasionally in humans. While populations of A. alternata from infected plants have received significant attention, relatively little is known about its soil populations, including its population genetic structure and antifungal susceptibilities. In addition, over the last two decades, greenhouses have become increasingly important for food and ornamental plant production throughout the world, but how greenhouses might impact microbial pathogens such as A. alternata populations remains largely unknown. Different from open crop fields, greenhouses are often more intensively cultivated, with each greenhouse being a relatively small and isolated space where temperature and humidity are higher than surrounding environments. Previous studies have shown that greenhouse populations of two common molds, Aspergillus fumigatus and A. alternata, within a small community in southwestern China were variably differentiated. However, the relative contribution of physical separation among local greenhouses to the large-scale population structure remains unknown. Here, we isolated strains of A. alternata from seven greenhouses in Shijiazhuang, northeast China. Their genetic diversity and triazole susceptibilities were analyzed and compared with each other and with 242 isolates from nine greenhouses in Kunming, southwest China. Results showed that the isolation of greenhouses located <1 km from each other locally contributed similarly to the overall genetic variation as that between the two distant geographic regions. In addition, our results indicate that greenhouses could be significant sources of triazole resistance, with greenhouses often differing in their frequencies of resistant strains to different triazoles. IMPORTANCE Greenhouses have become increasingly important for food production and food security. However, our understanding of how greenhouses may contribute to genetic variations in soil microbial populations is very limited. In this study, we obtained and analyzed soil populations of the cosmopolitan fungal pathogen Alternaria alternata in seven greenhouses in Shijiazhuang, northeast China. Our analyses revealed high proportions of isolates being resistant to agricultural triazole fungicides and medical triazole drugs, including cross-resistance to both groups of triazoles. In addition, we found that greenhouse populations of A. alternata located within a few kilometers showed similar levels of genetic differentiation as those separated by over 2,000 km between northeast and southwest China. Our study suggests that greenhouse populations of this and potentially other fungal pathogens represent an important ecological niche and an emerging threat to food security and human health.
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Affiliation(s)
- Guangzhu Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan, China
- College of Life Science, Yunnan University, Kunming, Yunnan, China
- Horticultural Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China
| | - Sai Cui
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan, China
- College of Life Science, Yunnan University, Kunming, Yunnan, China
| | - Wenjing Huang
- Horticultural Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China
| | - Shutong Wang
- College of Plant Protection, Hebei Agricultural University, Baoding, Hebei, China
| | - Jun Ma
- Horticultural Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China
| | - Ying Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan, China
| | - Jianping Xu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan, China
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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Schmey T, Tominello-Ramirez CS, Brune C, Stam R. Alternaria diseases on potato and tomato. MOLECULAR PLANT PATHOLOGY 2024; 25:e13435. [PMID: 38476108 DOI: 10.1111/mpp.13435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 01/27/2024] [Accepted: 01/29/2024] [Indexed: 03/14/2024]
Abstract
Alternaria spp. cause different diseases in potato and tomato crops. Early blight caused by Alternaria solani and brown spot caused by Alternaria alternata are most common, but the disease complex is far more diverse. We first provide an overview of the Alternaria species infecting the two host plants to alleviate some of the confusion that arises from the taxonomic rearrangements in this fungal genus. Highlighting the diversity of Alternaria fungi on both solanaceous hosts, we review studies investigating the genetic diversity and genomes, before we present recent advances from studies elucidating host-pathogen interactions and fungicide resistances. TAXONOMY Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes, Order Pleosporales, Family Pleosporaceae, Genus Alternaria. BIOLOGY AND HOST RANGE Alternaria spp. adopt diverse lifestyles. We specifically review Alternaria spp. that cause disease in the two solanaceous crops potato (Solanum tuberosum) and tomato (Solanum lycopersicum). They are necrotrophic pathogens with no known sexual stage, despite some signatures of recombination. DISEASE SYMPTOMS Symptoms of the early blight/brown spot disease complex include foliar lesions that first present as brown spots, depending on the species with characteristic concentric rings, which eventually lead to severe defoliation and considerable yield loss. CONTROL Good field hygiene can keep the disease pressure low. Some potato and tomato cultivars show differences in susceptibility, but there are no fully resistant varieties known. Therefore, the main control mechanism is treatment with fungicides.
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Affiliation(s)
- Tamara Schmey
- TUM School of Life Science Weihenstephan, Technical University of Munich, Freising, Germany
| | - Christopher S Tominello-Ramirez
- Department of Phytopathology and Crop Protection, Institute of Phytopathology, Christian Albrechts University, Kiel, Germany
| | - Carolin Brune
- TUM School of Life Science Weihenstephan, Technical University of Munich, Freising, Germany
| | - Remco Stam
- Department of Phytopathology and Crop Protection, Institute of Phytopathology, Christian Albrechts University, Kiel, Germany
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Li G, Zhang L, Li Y, Li X, Gao X, Dai T, Miao J, Liu X. Analysis of resistance risk and mechanism of the 14α-demethylation inhibitor ipconazole in Fusarium pseudograminearum. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 199:105786. [PMID: 38458686 DOI: 10.1016/j.pestbp.2024.105786] [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: 12/19/2023] [Revised: 01/07/2024] [Accepted: 01/09/2024] [Indexed: 03/10/2024]
Abstract
Ipconazole is a broad-spectrum triazole fungicide that is highly effective against Fusarium pseudograminearum. However, its risk of developing resistance and mechanism are not well understood in F. pseudograminearum. Here, the sensitivities of 101 F. pseudograminearum isolates to ipconazole were investigated, and the average EC50 value was 0.1072 μg/mL. Seven mutants resistant to ipconazole were obtained by fungicide adaption, with all but one showing reduced fitness relative to the parental isolates. Cross-resistance was found between ipconazole and mefentrifluconazole and tebuconazole, but none between ipconazole and pydiflumetofen, carbendazim, fludioxonil, or phenamacril. In summary, these findings suggest that there is a low risk of F. pseudograminearum developing resistance to ipconazole. Additionally, a point mutation, G464S, was seen in FpCYP51B and overexpression of FpCYP51A, FpCYP51B and FpCYP51C was observed in ipconazole-resistant mutants. Assays, including transformation and molecular docking, indicated that G464S conferred ipconazole resistance in F. pseudograminearum.
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Affiliation(s)
- Guixiang Li
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Ling Zhang
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Yiwen Li
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Xiong Li
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Xuheng Gao
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Tan Dai
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Jianqiang Miao
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China.
| | - Xili Liu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China; Department of Plant Pathology, College of Plant Protection, China Agricultural University, 2 Yuanmingyuanxi Road, Beijing 100193, China.
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Li G, Li X, Zeng Y, Liao S, Chen Y, Miao J, Peng Q, Liu X. Three point mutations in AaCYP51 combined with induced overexpression of AaCYP51 conferred low-level resistance to mefentrifluconazole in Alternaria alternata. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2023; 197:105677. [PMID: 38072534 DOI: 10.1016/j.pestbp.2023.105677] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/18/2023] [Accepted: 10/21/2023] [Indexed: 12/18/2023]
Abstract
Tomato early blight is a significant disease that causes substantial losses to tomato yield and quality. Mefentrifluconazole, an isopropanol-azole subgroup of triazole fungicides, has been registered in China for controlling various plant diseases, including tomato early blight, grape anthracnose, and apple brown spot. However, limited information is available on the mefentrifluconazole resistance risk and mechanism in plant pathogens. The sensitivity to mefentrifluconazole of 122 isolates of Alternaria alternata, one of the causal agents of tomato early blight, collected from different provinces in China, was evaluated. The results showed a unimodal curve for the sensitivity frequency, with an average EC50 of 0.306 μg/mL. Through fungicide adaption, six resistant mutants (N4, N5, T4, T5, NG1, and NG10) were obtained from three parental isolates, with a mutation frequency of 3.28 × 10-4 and resistance factors ranging between 19 and 147. The survival fitness of the resistant mutants, except for NG1, was significantly lower than that of their parental isolates. Positive cross-resistance was observed between mefentrifluconazole and difenoconazole or fenbuconazole, whereas no cross-resistance was found with three non-DMI fungicides. Furthermore, three distinct point mutations were detected in the AaCYP51 protein of the resistant mutants: I300S in T4 and T5; A303T in N4, NG1, and NG10; and A303V in N5. Compared to the parental isolates, the AaCYP51 gene was overexpressed in all six resistant mutants when treated with mefentrifluconazole. In summary, the resistance risk of A. alternata to mefentrifluconazole was low, and point mutations and overexpression of the AaCYP51 gene were identified as contributing factors to mefentrifluconazole resistance in A. alternata.
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Affiliation(s)
- Guixiang Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Xiuhuan Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Yan Zeng
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Shuailin Liao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Yue Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Jianqiang Miao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China
| | - Qin Peng
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China.
| | - Xili Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling 712100, Shaanxi, China; Department of Plant Pathology, College of Plant Protection, China Agricultural University, 2 Yuanmingyuanxi Road, Beijing 100193, China.
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Shi N, Qiu D, Chen F, Yang YQ, Du Y. Analysis of the Difenoconazole-Resistance Risk and Its Molecular Basis in Colletotrichum truncatum from Soybean. PLANT DISEASE 2023; 107:3123-3130. [PMID: 37172974 DOI: 10.1094/pdis-12-22-2983-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Anthracnose disease, caused by Colletotrichum truncatum, is a destructive fungal disease in soybean worldwide, and some demethylation inhibitor fungicides are used to manage it. In this study, the sensitivity of C. truncatum to difenoconazole was determined, and the risk for resistance development of C. truncatum to difenoconazole was also assessed. The results showed that the mean EC50 value was 0.9313 μg/ml, and the frequency of sensitivity formed a unimodal distribution. Six stable mutants with a mutation frequency of 8.33 × 10-5 were generated, and resistance factors ranged from 3.00 to 5.81 after 10 successive culture transfers. All mutants exhibited fitness penalties in reduced mycelial growth rate, sporulation, and pathogenicity, except for the Ct2-3-5 mutant. Positive cross-resistance was observed between difenoconazole and propiconazole but not between difenoconazole and prochloraz, pyraclostrobin, or fluazinam. One point mutation I463V in CYP51A was found in five resistant mutants. Surprisingly, the homologous I463V mutation has not been observed in other plant pathogens. CYP51A and CYP51B expression increased slightly in the resistant mutants as compared to wild-types when exposed to difenoconazole but not in the CtR61-2-3f and CtR61-2-4a mutants. In general, a new point mutation, I463V in CYP51A, could be associated with low resistance to difenoconazole in C. truncatum. In the greenhouse assay, control efficacy of difenoconazole on both parental isolates and the mutants increased in a dose-dependent manner. Collectively, the resistance risk of C. truncatum to difenoconazole is regarded to be low to moderate, suggesting that difenoconazole can still be reasonably used to control soybean anthracnose.
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Affiliation(s)
- Niuniu Shi
- Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350013, China
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Fuzhou, Fujian 350013, China
| | - Dezhu Qiu
- Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350013, China
| | - Furu Chen
- Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350013, China
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Fuzhou, Fujian 350013, China
| | - Ying-Qing Yang
- Institute of Plant Protection, Jiangxi Academy of Agricultural Sciences, Nanchang, Jiangxi 330000, China
| | - Yixin Du
- Institute of Plant Protection, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350013, China
- Fujian Key Laboratory for Monitoring and Integrated Management of Crop Pests, Fuzhou, Fujian 350013, China
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Hao G, Tian H, Zhang Z, Qin X, Yang T, Yuan L, Yang X. A dual-channel and dual-signal microfluidic paper chip for simultaneous rapid detection of difenoconazole and mancozeb. Microchem J 2023. [DOI: 10.1016/j.microc.2023.108674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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Wang C, Xu L, Liang X, Zhang Y, Zheng H, Chen J, Yang Y. Biochemical and Molecular Characterization of Prochloraz Resistance in Lasiodiplodia theobromae Field Isolates. PLANT DISEASE 2023; 107:177-187. [PMID: 35640950 DOI: 10.1094/pdis-10-21-2316-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Stem-end rot (SER), caused by Lasiodiplodia theobromae, is one of the most critical diseases of mango in China. The demethylation inhibitor fungicide prochloraz has been widely used in China to control mango diseases. Isolates (n = 139) of L. theobromae were collected in 2019 from six mango-producing regions in Hainan Province, China. The fungicide sensitivity of L. theobromae isolates to prochloraz revealed that the EC50 (50% effective concentration) values ranged from 0.0006 to 16.4131 µg/ml. In total, 21 of the 139 isolates were categorized as resistant to prochloraz. The resistant isolates sprayed with prochloraz could not be effectively controlled in detached fruit. The mycelial growth, conidia germination, and ability to grow at temperatures ranging from 12 to 35°C of resistant isolates decreased, suggesting fitness penalties. The experiment showed that, after treatment with prochloraz at 10 µg/ml, the content of ergosterol in the mycelia of the sensitive isolate decreased by 80.23%, whereas the resistant strain decreased by only 57.52%. The damage to membranes in the sensitive isolates was more serious than for resistant isolates. The target gene CYP51 and the ATP-binding cassette (ABC) subfamily ABCG gene were cloned but no mutation was found. When treated with prochloraz, the expression of CYP51 and ABCG in resistant isolates was significantly higher than in the sensitive isolates. Thus, induced expression of its target gene combined with the induction of expression drug efflux transporters appeared to mediate the prochloraz resistance of L. theobromae.
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Affiliation(s)
- Chenguang Wang
- College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China
| | - Luxi Xu
- College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China
| | - Xiaoyu Liang
- College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China
| | - Yu Zhang
- College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China
| | - HuiYing Zheng
- College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China
| | - JunLiu Chen
- College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China
| | - Ye Yang
- College of Plant Protection, Hainan University/Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Hainan University), Ministry of Education, Haikou 570228, China
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Santos FM, Viera LS, Camargo DP, Muniz MF, Costa IF, Guedes JV, Santos JR, Silva JC. Integrating a Bacillus-based product with fungicides by foliar application to protect soybean: a sustainable approach to avoid exclusive use of chemicals. PEST MANAGEMENT SCIENCE 2022; 78:4832-4840. [PMID: 35908173 DOI: 10.1002/ps.7104] [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: 01/21/2022] [Revised: 06/05/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Biological control is widely applied against soybean (Glycine max L.) soil-borne pathogens by furrow or seed treatments. The efficiency of bioproducts and timing of application by foliar sprays against soybean pathogens needs to be more fully understood. This work investigated the efficiency of foliar application with a Bacillus subtilis-based product (BBP) to protect soybean from multiple pathogens and the best moment to apply it considering its compatibility with fungicides. RESULTS Foliar applications (from stages V6 to R4) with BBP, mancozeb (M) and systemic fungicides (S) applied against Asian rust (Phakopsora pachyrhizi), BBP followed by S (BBP-S), BBP along with S (S + BBP), S along with M (S + M) or water were carried out in a soybean field for two years. The treatments S + BBP, S + M and BBP-S reduced the severity of Asian rust by 82% compared to the control. Except for M, all treatments reduced the severity of other foliar diseases by >60%. The defoliation was reduced by BBP and BBP-S, whereas the yield was 25% higher than control by using BBP, S + M, S + BBP or BBP-S. Also, the incidence of Fusarium sp. was significantly reduced on seeds from treatments BBP and BBP-S. The compatibility tests in Petri dishes demonstrated that all fungicides decreased the bacterial growth when applied along with BBP, whereas previous applications of BBP did not reduce the bacterial growth. CONCLUSIONS The BBP protected soybean against multiple pathogens, reduced defoliation and promoted soybean yield similarly to conventional fungicides, but in general, the early application of the BBP was the most efficient protection. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Fabio M Santos
- Department of Phytosanitary Defense, CCR, Federal University of Santa Maria, (UFSM), Santa Maria, Brazil
| | - Laura S Viera
- Department of Phytosanitary Defense, CCR, Federal University of Santa Maria, (UFSM), Santa Maria, Brazil
| | - Darcila P Camargo
- Department of Phytosanitary Defense, CCR, Federal University of Santa Maria, (UFSM), Santa Maria, Brazil
| | - Marlove Fb Muniz
- Department of Phytosanitary Defense, CCR, Federal University of Santa Maria, (UFSM), Santa Maria, Brazil
| | - Ivan Fd Costa
- Department of Phytosanitary Defense, CCR, Federal University of Santa Maria, (UFSM), Santa Maria, Brazil
| | - Jerson Vc Guedes
- Department of Phytosanitary Defense, CCR, Federal University of Santa Maria, (UFSM), Santa Maria, Brazil
| | - Jansen Rp Santos
- Department of Phytosanitary Defense, CCR, Federal University of Santa Maria, (UFSM), Santa Maria, Brazil
| | - Julio Cp Silva
- Department of Phytosanitary Defense, CCR, Federal University of Santa Maria, (UFSM), Santa Maria, Brazil
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Ke D, Meng H, Lei W, Zheng Y, Li L, Wang M, Zhong R, Wang M, Chen F. Prevalence of H6Y mutation in β-tubulin causing thiophanate-methyl resistant in Monilinia fructicola from Fujian, China. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 188:105262. [PMID: 36464367 DOI: 10.1016/j.pestbp.2022.105262] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/26/2022] [Accepted: 10/07/2022] [Indexed: 06/17/2023]
Abstract
Brown rot disease broke out in stone fruit orchards of Fujian, China in 2019, despite pre-harvest application of methyl benzimidazole carbamate (MBC). To determine the reason, a total of 44 Monilinia fructicola strains were collected from nectarine, plum and peach fruits in this study, among which 79.5% strains were resistant to thiophanate-methyl, indicated by discriminatory dose of 5 μg/mL. The resistance of these strains was confirmed by treating detached peach fruit with label rates of formulated thiophanate-methyl which only completely inhibit infection of the sensitive strains, but not the resistant strains. Further analysis of the mechanism of MBC resistance revealed that all resistant strains carry a H6Y mutation in β-tubulin protein Tub2, which was only reported previously in the M. fructicola strains from California, USA, and do not display obvious fitness penalties, as no significant defects in mycelial growth rate, sporulation, conidia germination, aggressiveness on detached peach fruit and temperature sensitivity was detected. In addition, we found that diethofencarb, the agent for managing MBC-resistance strains, was unable to inhibit growth of the H6Y strains. Taken together, our study, for the first time, identified a mutation form of H6Y in the β-tubulin protein of M. fructicola in China, rendering the strains wide resistance to thiophanate-methyl. This mechanism of M. fructicola gaining resistance to MBC fungicides needs to be fully considered, when designing management strategies to control brown rot disease in stone fruit orchards.
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Affiliation(s)
- Dufang Ke
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Han Meng
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Universities Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Wenting Lei
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yulong Zheng
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Linhan Li
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mingyi Wang
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Rui Zhong
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mo Wang
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China; Fujian Universities Key Laboratory for Plant-Microbe Interaction, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Fengping Chen
- Key Laboratory of Biopesticides and Chemical Biology, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou 350002, China; State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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Wei L, Li X, Chen B, Chen W, Wei L, Zhou D, Chen C, Wu C. Sterol 14α-Demethylase CaCYP51A and CaCYP51B are Functionally Redundant, but Differentially Regulated in Colletotrichum acutatum: Responsibility for DMI-Fungicide Resistance. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:11911-11922. [PMID: 36102348 DOI: 10.1021/acs.jafc.2c04824] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Colletotrichum acutatum, the main pathogen causing anthracnose on chili worldwide, is controlled by tebuconazole [a sterol C14-demethylation inhibitor (DMI) fungicide, abbreviated as Teb] with excellent efficacy. Our previous study exhibited that all C. acutatum isolates were sensitive to Teb while the Colletotrichum gloeosporioides population had developed resistance to Teb on the same fungicide-pressure selection. Therefore, the assessment of Teb-resistance in C. acutatum is impending. Twenty Teb-resistant (TebR) mutants obtained by fungicide domestication and ultraviolet (UV)-mutagenesis displayed similar fitness compared to parental isolates. Data in the current study exhibited that mutations at CaCYP51A and/or overexpression of CaCYP51s were responsible for Teb-resistance. Furthermore, the deletion mutants ΔCaCYP51A and ΔCaCYP51B played different roles in sensitivities to DMIs. Taken together, this study first reported that mutations at CaCYP51A and/or overexpression of CaCYP51s conferred resistance to Teb in C. acutatum, CaCYP51A and CaCYP51B are functionally redundant, but differentially regulated in DMI resistance.
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Affiliation(s)
- Lingling Wei
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Xiujuan Li
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Bin Chen
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Wenchan Chen
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210095, Jiangsu, China
| | - Lihui Wei
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210095, Jiangsu, China
| | - Dongmei Zhou
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210095, Jiangsu, China
| | - Changjun Chen
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, Jiangsu, China
| | - Chengdong Wu
- Nanjing Pukou District Agricultural Technology Extension Center, Nanjing 211800, Jiangsu, China
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11
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Yang G, Cui S, Ma N, Song Y, Ma J, Huang W, Zhang Y, Xu J. Genetic Structure and Triazole Antifungal Susceptibilities of Alternaria alternata from Greenhouses in Kunming, China. Microbiol Spectr 2022; 10:e0038222. [PMID: 35546576 PMCID: PMC9241833 DOI: 10.1128/spectrum.00382-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 04/22/2022] [Indexed: 11/20/2022] Open
Abstract
Alternaria alternata is an opportunistic human fungal pathogen and a ubiquitous phytopathogen capable of causing diseases to >100 agricultural crops and ornamental plants. To control plant diseases caused by A. alternata, triazole fungicides have been widely used both in open crop and vegetable fields and in indoor growth facilities such as greenhouses. At present, the effect of fungicide use on triazole resistance development in A. alternata populations is not known. Here, we isolated 237 A. alternata strains from nine greenhouses around metropolitan Kunming in Yunnan, southwest China, determined their genotypes using 10 short tandem repeat markers, and quantified their susceptibility to four triazoles (difenoconazole, tebuconazole, itraconazole, and voriconazole). Abundant allelic and genotypic diversities were detected among these A. alternata strains. Significantly, over 17% of the strains were resistant to difenoconazole, and both known and new drug-resistance mutations were found in the triazole target gene cyp51. Our findings of high-level genetic variation of A. alternata in greenhouses coupled with high-frequency fungicide resistance call for greater attention to continued monitoring and to developing alternative plant fungal disease management strategies in greenhouses. IMPORTANCE Alternaria alternata is among the most common fungi in our environments, such as indoor facilities, the soil, and outdoor air. It can cause diseases in >100 crop and ornamental plants. Furthermore, it can cause human infections. However, our understanding of its genetic diversity and antifungal susceptibility is very limited. Indeed, the critical threshold values for resistance have not been defined for most antifungal drugs in this species. Greenhouses are known to have heavy applications of agricultural fungicides. In this study, we analyzed strains of A. alternata from nine greenhouses near metropolitan Kunming in southwestern China. Our study revealed very high genetic diversity and identified strains with high MIC values against two agricultural and two medical triazole antifungals within each of the nine greenhouses. Our study calls for greater attention to this emerging threat to food security and human health.
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Affiliation(s)
- Guangzhu Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, People’s Republic of China
- School of Life Science, Yunnan University, Kunming, People’s Republic of China
- Horticultural Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, People’s Republic of China
| | - Sai Cui
- School of Life Science, Yunnan University, Kunming, People’s Republic of China
| | - Nan Ma
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, People’s Republic of China
| | - Yuansha Song
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, People’s Republic of China
| | - Jun Ma
- Horticultural Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, People’s Republic of China
| | - Wenjing Huang
- Horticultural Research Institute, Yunnan Academy of Agricultural Sciences, Kunming, People’s Republic of China
| | - Ying Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, People’s Republic of China
| | - Jianping Xu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Key Laboratory for Southwest Microbial Diversity of the Ministry of Education, Yunnan University, Kunming, People’s Republic of China
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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12
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Einspanier S, Susanto T, Metz N, Wolters PJ, Vleeshouwers VG, Lankinen Å, Liljeroth E, Landschoot S, Ivanović Ž, Hückelhoven R, Hausladen H, Stam R. Whole genome sequencing elucidates the species‐wide diversity and evolution of fungicide resistance in the early blight pathogen
Alternaria solani. Evol Appl 2022; 15:1605-1620. [PMID: 36330303 PMCID: PMC9624079 DOI: 10.1111/eva.13350] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 11/28/2022] Open
Abstract
Early blight of potato is caused by the fungal pathogen Alternaria solani and is an increasing problem worldwide. The primary strategy to control the disease is applying fungicides such as succinate dehydrogenase inhibitors (SDHI). SDHI‐resistant strains, showing reduced sensitivity to treatments, appeared in Germany in 2013, shortly after the introduction of SDHIs. Two primary mutations in the SDH complex (SdhB‐H278Y and SdhC‐H134R) have been frequently found throughout Europe. How these resistances arose and spread, and whether they are linked to other genomic features, remains unknown. For this project, we performed whole‐genome sequencing for 48 A. solani isolates from potato fields across Europe to better characterize the pathogen's genetic diversity in general and understand the development and spread of the genetic mutations that lead to SDHI resistance. The isolates can be grouped into seven genotypes. These genotypes do not show a geographical pattern but appear spread throughout Europe. We found clear evidence for recombination on the genome, and the observed admixtures might indicate a higher adaptive potential of the fungus than previously thought. Yet, we cannot link the observed recombination events to different Sdh mutations. The same Sdh mutations appear in different, non‐admixed genetic backgrounds; therefore, we conclude they arose independently. Our research gives insights into the genetic diversity of A. solani on a genome level. The mixed occurrence of different genotypes, apparent admixture in the populations, and evidence for recombination indicate higher genomic complexity than anticipated. The conclusion that SDHI tolerance arose multiple times independently has important implications for future fungicide resistance management strategies. These should not solely focus on preventing the spread of isolates between locations but also on limiting population size and the selective pressure posed by fungicides in a given field to avoid the rise of new mutations in other genetic backgrounds.
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Affiliation(s)
| | - Tamara Susanto
- Chair of Phytopathology Technical University of Munich Freising Germany
| | - Nicole Metz
- Chair of Phytopathology Technical University of Munich Freising Germany
| | - Pieter J. Wolters
- Plant Breeding Wageningen University and Research Wageningen The Netherlands
| | | | - Åsa Lankinen
- Department of Plant Protection Swedish University of Agricultural Sciences Lomma Sweden
| | - Erland Liljeroth
- Department of Plant Protection Swedish University of Agricultural Sciences Lomma Sweden
| | | | - Žarko Ivanović
- Institute for Plant Protection and Environment Belgrade Serbia
| | - Ralph Hückelhoven
- Chair of Phytopathology Technical University of Munich Freising Germany
| | - Hans Hausladen
- Plant Technology Centre Technical University of Munich Freising Germany
| | - Remco Stam
- Chair of Phytopathology Technical University of Munich Freising Germany
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13
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Moore LC, Brenneman TB, Waliullah S, Bock CH, Ali ME. Multiple Mutations and Overexpression in the CYP51A and B Genes Lead to Decreased Sensitivity of Venturia effusa to Tebuconazole. Curr Issues Mol Biol 2022; 44:670-685. [PMID: 35723332 PMCID: PMC8928975 DOI: 10.3390/cimb44020047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 11/16/2022] Open
Abstract
Multiple demethylation-inhibiting (DMI) fungicides are used to control pecan scab, caused by Venturia effusa. To compare the efficacy of various DMI fungicides on V. effusa, field trials were conducted at multiple locations applying fungicides to individual pecan terminals. In vitro assays were conducted to test the sensitivity of V. effusa isolates from multiple locations to various concentrations of tebuconazole. Both studies confirmed high levels of resistance to tebuconazole. To investigate the mechanism of resistance, two copies of the CYP51 gene, CYP51A and CYP51B, of resistant and sensitive isolates were sequenced and scanned for mutations. In the CYP51A gene, mutation at codon 444 (G444D), and in the CYP51B gene, mutations at codon 357 (G357H) and 177 (I77T/I77L) were found in resistant isolates. Expression analysis of CYP51A and CYP51B revealed enhanced expression in the resistant isolates compared to the sensitive isolates. There were 3.0- and 1.9-fold increases in gene expression in the resistant isolates compared to the sensitive isolates for the CYP51A and CYP51B genes, respectively. Therefore, two potential mechanisms—multiple point mutations and gene over expression in the CYP51 gene of V. effusa isolates—were revealed as likely reasons for the observed resistance in isolates of V. effusa to tebuconazole.
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Affiliation(s)
- Logan C. Moore
- Department of Plant Pathology, Coastal Plain Experiment Station, The University of Georgia, Tifton, GA 31793, USA; (L.C.M.); (T.B.B.); (S.W.)
| | - Timothy B. Brenneman
- Department of Plant Pathology, Coastal Plain Experiment Station, The University of Georgia, Tifton, GA 31793, USA; (L.C.M.); (T.B.B.); (S.W.)
| | - Sumyya Waliullah
- Department of Plant Pathology, Coastal Plain Experiment Station, The University of Georgia, Tifton, GA 31793, USA; (L.C.M.); (T.B.B.); (S.W.)
| | - Clive H. Bock
- United States Department of Agriculture-Agricultural Research Service Southeastern Fruit and Tree Nut Research Station, Byron, GA 31008, USA;
| | - Md Emran Ali
- Department of Plant Pathology, Coastal Plain Experiment Station, The University of Georgia, Tifton, GA 31793, USA; (L.C.M.); (T.B.B.); (S.W.)
- Correspondence:
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14
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Hudson O, Waliullah S, Ji P, Ali ME. Molecular Characterization of Laboratory Mutants of Fusarium oxysporum f. sp. niveum Resistant to Prothioconazole, a Demethylation Inhibitor (DMI) Fungicide. J Fungi (Basel) 2021; 7:jof7090704. [PMID: 34575742 PMCID: PMC8466437 DOI: 10.3390/jof7090704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/21/2021] [Accepted: 08/24/2021] [Indexed: 12/26/2022] Open
Abstract
Fusarium oxysporum f. sp. niveum (FON) is the causal agent of Fusarium wilt in watermelon, an international growth-limiting pathogen of watermelon cultivation. A single demethylation inhibitor (DMI) fungicide, prothioconazole, is registered to control this pathogen, so the risk of resistance arising in the field is high. To determine and predict the mechanism by which FON could develop resistance to prothioconazole, FON isolates were mutagenized using UV irradiation and subsequent fungicide exposure to create artificially resistant mutants. Isolates were then put into three groups based on the EC50 values: sensitive, intermediately resistant, and highly resistant. The mean EC50 values were 4.98 µg/mL for the sensitive, 31.77 µg/mL for the intermediately resistant, and 108.33 µg/mL for the highly resistant isolates. Isolates were then sequenced and analyzed for differences in both the coding and promoter regions. Two mutations were found that conferred amino acid changes in the target gene, CYP51A, in both intermediately and highly resistant mutants. An expression analysis for the gene CYP51A also showed a significant increase in the expression of the highly resistant mutants compared to the sensitive controls. In this study, we were able to identify two potential mechanisms of resistance to the DMI fungicide prothioconazole in FON isolates: gene overexpression and multiple point mutations. This research should expedite growers’ and researchers’ ability to detect and manage fungicide-resistant phytopathogens.
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15
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Zhang C, Imran M, Xiao L, Hu Z, Li G, Zhang F, Liu X. Difenoconazole Resistance Shift in Botrytis cinerea From Tomato in China Associated With Inducible Expression of CYP51. PLANT DISEASE 2021; 105:400-407. [PMID: 32729807 DOI: 10.1094/pdis-03-20-0508-re] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Gray mold caused by Botrytis cinerea is one of the most important diseases in tomato. It can be controlled effectively by demethylation inhibitor (DMI) fungicides, but their resistance status after long-term use in the field is unclear. The baseline sensitivity to difenoconazole of 142 B. cinerea isolates from China with no history of DMI usage was characterized, with a mean effective concentration for 50% mycelial growth inhibition (EC50) of 0.97 ± 0.50 μg/ml. EC50 values for difenoconazole sensitivity of another 248 isolates collected in 2011 and 2016 ranged from 0.04 to 11.99 μg/ml, and the frequency of difenoconazole sensitivity formed a nonnormal distribution curve. Detached fruit studies revealed that isolates with EC50 values of approximately 6.00 μg/ml were not controlled effectively. The mean EC50 of the resistant isolates changed from 6.74 to 8.65 μg/ml between 2011 and 2016. Positive cross-resistance was only observed between difenoconazole and two DMIs. One dual resistant isolate and one triple resistant isolate were found among the difenoconazole-resistant isolates collected in 2016, associated with point mutations in corresponding target proteins of the fungicides azoxystrobin and fludioxonil. This indicated that B. cinerea not only showed higher difenoconazole resistance levels but gradually changed from single to multiple fungicide resistance over time. No amino acid variation was found in the CYP51 protein. In the absence of difenoconazole, the relative expression of CYP51 was not significantly different in sensitive and resistant isolates. Induced expression of CYP51 is an important determinant of DMI resistance in B. cinerea from tomato. However, nucleotide variants found in the upstream region had no association with the fungicide resistance phenotype. These results will be helpful for the management of B. cinerea in the field.
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Affiliation(s)
- Can Zhang
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Muhammad Imran
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Lu Xiao
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Zhihong Hu
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Guixiang Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, China
| | - Fan Zhang
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Xili Liu
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, China
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16
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Ishii H, Bryson PK, Kayamori M, Miyamoto T, Yamaoka Y, Schnabel G. Cross-resistance to the new fungicide mefentrifluconazole in DMI-resistant fungal pathogens. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 171:104737. [PMID: 33357559 DOI: 10.1016/j.pestbp.2020.104737] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 06/12/2023]
Abstract
In the European Union (EU), regulation of sterol demethylation inhibiting (DMI) fungicides is tightened due to their suspected endocrine disrupting properties. However, the new DMI fungicide mefentrifluconazole was reported to have high fungicidal activity with minimal adverse side effects. In addition, some evidence suggests inconsistent cross resistance between mefentrifluconazole and other azoles. In this study, mefentrifluconazole and other triazoles were examined for activity to select pathogens sensitive or resistant to DMIs using mycelial growth tests on fungicide-treated culture medium or spray trials using cucumber plants. Cross-resistance was confirmed for all of the fungal species tested but activity levels varied. The sensitivity of Monilinia fructicola from peach to mefentrifluconazole was higher compared to other DMIs. In contrast, the inhibitory activity of mefentrifluconazole was equal or slightly inferior compared to difenoconazole, tebuconazole, propiconazole in Colletotrichum spp., Alternaria alternaria sp. complex and Cercospora beticola isolated from peach and sugar beet, respectively. Similar tendencies (i.e. equal or slightly inferior activity and cross-resistance) were observed for cucumber powdery mildew (Podosphaera xanthii) resistant to triflumizole, myclobutanil, and difenoconazole. Despite cross-resistance to other DMIs, mefentrifluconazole is a promising fungicide for fungal disease control on peach and other crops, with a reportedly more favorable toxicity profile.
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Affiliation(s)
- Hideo Ishii
- University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan; Clemson University, 105 Collings St., Clemson, SC 29634, USA.
| | | | - Miyuki Kayamori
- Tokachi Agricultural Experiment Station, Hokkaido Research Organization, Memuro, Kasai, Hokkaido 082-0081, Japan
| | - Takuya Miyamoto
- Horticultural Research Institute, Ibaraki Agricultural Centre, 3165-1 Ago, Kasama, Ibaraki 312-0292, Japan
| | - Yuichi Yamaoka
- University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan
| | - Guido Schnabel
- Clemson University, 105 Collings St., Clemson, SC 29634, USA.
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Zhang C, Imran M, Liu M, Li Z, Gao H, Duan H, Zhou S, Liu X. Two Point Mutations on CYP51 Combined With Induced Expression of the Target Gene Appeared to Mediate Pyrisoxazole Resistance in Botrytis cinerea. Front Microbiol 2020; 11:1396. [PMID: 32714305 PMCID: PMC7340008 DOI: 10.3389/fmicb.2020.01396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 05/29/2020] [Indexed: 11/24/2022] Open
Abstract
Botrytis cinerea is a destructive plant pathogenic ascomycete that causes serious pre- and post-harvest losses worldwide. The novel sterol 14α-demethylase inhibitor (DMI) pyrisoxazole was recently registered for the control of tomato gray mold caused by B. cinerea in China. Baseline sensitivity of 110 B. cinerea isolates collected from nine provinces in China to pyrisoxazole was demonstrated, with a mean EC50 of 0.057 ± 0.029 μg/ml. Eleven stable mutants resistant to pyrisoxazole were generated via UV irradiation (RU-mutants) and spontaneous selection (RS-mutants) of conidia. The efficacy of pyrisoxazole against the resistant mutants was significantly lower than that of the sensitive isolates. Most of the pyrisoxazole- resistant mutants were less fit than the sensitive isolates, with reduced sporulation, conidia germination, sclerotium production, and pathogenicity, which was confirmed by the competitive ability test. Positive cross-resistance was only observed between pyrisoxazole and the DMIs tebuconazole and prochloraz, but not between pyrisoxazole and non-DMIs iprodione, procymidone, diethofencarb, fluazinam, pyrimethanil, or fludioxonil. A two-point mutation, at G476S and K104E in the RU-mutants, and a one point mutation, M231T, in the RS-mutants, were detected in the CYP51 protein of the resistant mutants. When exposed to pyrisoxazole, the induced expression level of CYP51 increased in the resistant isolates as compared to sensitive ones. Molecular docking suggested that G476S and M231T mutations both led to the loss of electrostatic interactions between CYP51 and pyrisoxazole, while no change was found with the K104E mutation. Thus, two point mutations on CYP51 protein combined with induced expression of its target gene appeared to mediate the pyrisoxazole resistance of B cinerea.
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Affiliation(s)
- Can Zhang
- China Agricultural University, Beijing, China
| | | | - Min Liu
- China Agricultural University, Beijing, China
| | - Zhiwen Li
- Institute for the Control of Agrochemicals of Shaanxi Province, Xi'an, China
| | - Huige Gao
- China Agricultural University, Beijing, China
| | | | - Shunli Zhou
- China Agricultural University, Beijing, China
| | - Xili Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, China
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