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Dorigan AF, Moreira SI, da Silva Costa Guimarães S, Cruz-Magalhães V, Alves E. Target and non-target site mechanisms of fungicide resistance and their implications for the management of crop pathogens. PEST MANAGEMENT SCIENCE 2023; 79:4731-4753. [PMID: 37592727 DOI: 10.1002/ps.7726] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/14/2023] [Accepted: 08/18/2023] [Indexed: 08/19/2023]
Abstract
Fungicides are indispensable for high-quality crops, but the rapid emergence and evolution of fungicide resistance have become the most important issues in modern agriculture. Hence, the sustainability and profitability of agricultural production have been challenged due to the limited number of fungicide chemical classes. Resistance to site-specific fungicides has principally been linked to target and non-target site mechanisms. These mechanisms change the structure or expression level, affecting fungicide efficacy and resulting in different and varying resistance levels. This review provides background information about fungicide resistance mechanisms and their implications for developing anti-resistance strategies in plant pathogens. Here, our purpose was to review changes at the target and non-target sites of quinone outside inhibitor (QoI) fungicides, methyl-benzimidazole carbamate (MBC) fungicides, demethylation inhibitor (DMI) fungicides, and succinate dehydrogenase inhibitor (SDHI) fungicides and to evaluate if they may also be associated with a fitness cost on crop pathogen populations. The current knowledge suggests that understanding fungicide resistance mechanisms can facilitate resistance monitoring and assist in developing anti-resistance strategies and new fungicide molecules to help solve this issue. © 2023 Society of Chemical Industry.
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Affiliation(s)
| | | | | | | | - Eduardo Alves
- Department of Plant Pathology, Federal University of Lavras, Lavras, Brazil
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2
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Heaven T, Armitage AD, Xu X, Goddard MR, Cockerton HM. Dose-Dependent Genetic Resistance to Azole Fungicides Found in the Apple Scab Pathogen. J Fungi (Basel) 2023; 9:1136. [PMID: 38132737 PMCID: PMC10744243 DOI: 10.3390/jof9121136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/13/2023] [Accepted: 11/17/2023] [Indexed: 12/23/2023] Open
Abstract
The evolution of azole resistance in fungal pathogens presents a major challenge in both crop production and human health. Apple orchards across the world are faced with the emergence of azole fungicide resistance in the apple scab pathogen Venturia inaequalis. Target site point mutations observed in this fungus to date cannot fully explain the reduction in sensitivity to azole fungicides. Here, polygenic resistance to tebuconazole was studied across a population of V. inaequalis. Genotyping by sequencing allowed Quantitative Trait Loci (QTLs) mapping to identify the genetic components controlling this fungicide resistance. Dose-dependent genetic resistance was identified, with distinct genetic components contributing to fungicide resistance at different exposure levels. A QTL within linkage group seven explained 65% of the variation in the effective dose required to reduce growth by 50% (ED50). This locus was also involved in resistance at lower fungicide doses (ED10). A second QTL in linkage group one was associated with dose-dependent resistance, explaining 34% of variation at low fungicide doses (ED10), but did not contribute to resistance at higher doses (ED50 and ED90). Within QTL regions, non-synonymous mutations were observed in several ATP-Binding Cassette and Major Facilitator SuperFamily transporter genes. These findings provide insight into the mechanisms of fungicide resistance that have evolved in horticultural pathogens. Identification of resistance gene candidates supports the development of molecular diagnostics to inform management practices.
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Affiliation(s)
- Thomas Heaven
- National Institute of Agricultural Botany, New Road, East Malling, West Malling, Kent ME19 6BJ, UK;
- The School of Life and Environmental Sciences, University of Lincoln, Lincoln LN6 7DL, UK;
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | | | - Xiangming Xu
- National Institute of Agricultural Botany, New Road, East Malling, West Malling, Kent ME19 6BJ, UK;
| | - Matthew R. Goddard
- The School of Life and Environmental Sciences, University of Lincoln, Lincoln LN6 7DL, UK;
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Li Y, Wang Y, Li X, Fan H, Gao X, Peng Q, Li F, Lu L, Miao J, Liu X. Resistant risk and resistance-related point mutation in SdhC 1 of pydiflumetofen in Fusarium pseudograminearum. PEST MANAGEMENT SCIENCE 2023; 79:4197-4207. [PMID: 37326415 DOI: 10.1002/ps.7616] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 06/09/2023] [Accepted: 06/16/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Fusarium pseudograminearum is one of the dominant pathogens of Fusarium crown rot (FCR) worldwide. Unfortunately, no fungicides have yet been registered for the control of FCR in wheat in China. Pydiflumetofen, a new-generation succinate dehydrogenase inhibitor, exhibits excellent inhibitory activity to Fusarium spp. A resistance risk assessment of F. pseudograminearum to pydiflumetofen and the resistance mechanism involved have not yet been investigated. RESULTS The median effective concentration (EC50 ) value of 103 F. pseudograminearum isolates to pydiflumetofen was 0.0162 μg mL-1 , and the sensitivity exhibited a unimodal distribution. Four resistant mutants were generated by fungicide adaption, which possessed similar or impaired fitness compared to corresponding parental isolates based on the results of mycelial growth, conidiation, conidium germination rate, and virulence determination. Pydiflumetofen showed strong positive cross-resistance with cyclobutrifluram and fluopyram but no cross-resistance with carbendazim, phenamacril, tebuconazole, fludioxonil, or pyraclostrobin. Sequence alignment revealed that pydiflumetofen-resistant F. pseudograminearum mutants had two single-point mutations of A83V or R86K in FpSdhC1 . Molecular docking further confirmed that point mutation of A83V or R86K in FpSdhC1 could confer resistance of F. pseudograminearum to pydiflumetofen. CONCLUSION Fusarium pseudograminearum shows an overall moderate risk of developing resistance to pydiflumetofen, and point mutation FpSdhC1 A83V or FpSdhC1 R86K could confer pydiflumetofen resistance in F. pseudograminearum. This study provided vital data for monitoring the emergence of resistance and developing resistance management strategies for pydiflumetofen. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Yiwen Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Yan Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Xinyue Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Hengjun Fan
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Xuheng Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Qin Peng
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Feng Li
- Department of Plant Protection and Development, Syngenta (China) Investment Co., Ltd., Shanghai, China
| | - Liang Lu
- Department of Plant Protection and Development, Syngenta (China) Investment Co., Ltd., Shanghai, China
| | - Jianqiang Miao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
| | - Xili Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, China
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
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Liu Y, Sun Y, Bai Y, Cheng X, Li H, Chen X, Chen Y. Study on Mechanisms of Resistance to SDHI Fungicide Pydiflumetofen in Fusarium fujikuroi. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:14330-14341. [PMID: 37729092 DOI: 10.1021/acs.jafc.3c03678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Rice bakaenii disease (RBD) is a widespread and devastating disease mainly caused by Fusarium fujikuroi. Pydiflumetofen (Pyd) is a novel succinate dehydrogenase inhibitor (SDHI) with strong inhibitory activity against F. fujikuroi, but the mechanism of resistance to Pyd has not been well studied for this pathogen. Through fungicide adaption, a total of 12 Pyd-resistant mutants were obtained and the resistance level could be divided into three categories of high resistance (HR), moderate resistance (MR), and low resistance (LR) with resistance factors (RF) of 184.04-672.90, 12.63-42.49, and <10, respectively. Seven genotypes of point mutations in FfSdh genes (FfSdhBH248L, FfSdhBH248D, FfSdhBH248Y, FfSdhC2A83V, FfSdhC2H144Y, FfSdhDS106F, and FfSdhDE166K) were found in these mutants, among which genotype FfSdhBH248L and FfSdhC2A83V mutants showed HR, genotype FfSdhBH248D, FfSdhBH248Y, FfSdhC2H144Y, and FfSdhDE166K mutants showed MR, and genotype FfSdhDS106F mutants showed LR. Moreover, all the substitutions of amino acid point mutations including FfSdhBH248L/D/Y, FfSdhC2A83V,H144Y, and FfSdhDS106F,E166K conferring resistance to Pyd in F. fujikuroi were verified by protoplast transformation. Additionally, a positive cross-resistance was detected between Pyd and another SDHI fungicide penflufen, while no cross-resistance was detected between Pyd and phenamacril, prochloraz, azoxystrobin, carbendazim, or fludioxonil. Although pathogenicity of the mutants was increased compared with that of the wild-type parental strains, the mycelial growth rate and spore production levels of the resistant mutants were significantly decreased (P < 0.05), indicating significant fitness cost of resistance to Pyd in F. fujikuroi. Taken together, the risk of resistance to Pyd in F. fujikuroi might be moderate, and appropriate precautions against resistance development in natural populations should be taken into account when Pyd is used for the control of RBD.
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Affiliation(s)
- Yu Liu
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Yang Sun
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Key Laboratory of Integrated Crop Pest Management of Anhui Province, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Yang Bai
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Xin Cheng
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Hui Li
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Xing Chen
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Key Laboratory of Integrated Crop Pest Management of Anhui Province, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Yu Chen
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Key Laboratory of Integrated Crop Pest Management of Anhui Province, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
- Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China
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Liu Y, Del Rio Mendoza LE, Qi A, Lakshman D, Bhuiyan MZR, Wyatt N, Neubauer J, Bolton M, Khan MFR. Resistance to QoI and DMI Fungicides Does Not Reduce Virulence of C. beticola Isolates in North Central United States. PLANT DISEASE 2023; 107:2825-2829. [PMID: 36825317 DOI: 10.1094/pdis-11-21-2583-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: 06/18/2023]
Abstract
Cercospora leaf spot (CLS) is a destructive disease limiting sugar beet production and is managed using resistant cultivars, crop rotation, and timely applications of effective fungicides. Since 2016, its causal agent, Cercospora beticola, has been reported to be resistant to quinone outside inhibitors (QoIs) and to have reduced sensitive to demethylation inhibitors (DMIs) in sugar beet growing areas in North Dakota and Minnesota. Isolates of C. beticola resistant to QoIs, DMIs, and both QoIs and DMIs were collected from fields in Foxhome, Minnesota, in 2017. Fitness of these resistant isolates was compared with that of QoI- and DMI-sensitive isolates in laboratory and greenhouse studies. In the lab, mycelial growth, spore production, and spore germination were measured. The results showed that resistant isolates had significantly less mycelial growth and spore production than sensitive isolates, while no significant difference in spore germination was detected. In the greenhouse, six leaf-stage sugar beets were inoculated with a spore suspension made from each resistant group and incubated in separate humidity chambers. CLS disease severity was evaluated visually at 7, 14, and 21 days after inoculation (DAI), and the areas under disease progress curve (AUDPC) were calculated. Resistant isolates had significantly smaller AUDPC but still caused as high disease severity as the sensitive ones at 21 DAI. Although QoI- and/or DMI-resistant isolates had a relatively slower disease development, they still caused high disease severity and need to be factored in disease management practices.
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Affiliation(s)
- Yangxi Liu
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
| | | | - Aiming Qi
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, U.K
| | - Dilip Lakshman
- Sustainable Agricultural Systems Laboratory, USDA-ARS, Beltsville, MD 20705, U.S.A
| | - M Z R Bhuiyan
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
| | | | | | | | - Mohamed F R Khan
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108, U.S.A
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Moureu S, Jacquin J, Samaillie J, Deweer C, Rivière C, Muchembled J. Antifungal Activity of Hop Leaf Extracts and Xanthohumol on Two Strains of Venturia inaequalis with Different Sensitivities to Triazoles. Microorganisms 2023; 11:1605. [PMID: 37375106 DOI: 10.3390/microorganisms11061605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Hop cones are well-known for their antimicrobial properties, attributed to their specialized metabolites. Thus, this study aimed to determine the in vitro antifungal activity of different hop parts, including by-products such as leaves and stems, and some metabolites against Venturia inaequalis, the causal agent of apple scab. For each plant part, two types of extracts, a crude hydro-ethanolic extract and a dichloromethane sub-extract, were tested on spore germination of two strains with different sensitivities to triazole fungicides. Both extracts of cones, leaves and stems were able to inhibit the two strains, whereas rhizomes did not show activity. The apolar sub-extract of leaves appeared as the most active modality tested with half maximal inhibitory concentrations (IC50) of 5 and 10.5 mg·L-1 on the sensitive strain and the strain with reduced sensitivity, respectively. Differences in activity level between strains were noticed for all active modalities tested. Sub-extracts of leaves were then separated into seven fractions by preparative HPLC and tested on V. inaequalis. One fraction, containing xanthohumol, was especially active on both strains. This prenylated chalcone was then purified by preparative HPLC and showed significant activity against both strains, with IC50 of 1.6 and 5.1 mg·L-1. Therefore, xanthohumol seems to be a promising compound to control V. inaequalis.
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Affiliation(s)
- Sophie Moureu
- Joint Research Unit 1158 BioEcoAgro, INRAE, University of Lille, JUNIA, University of Liège, UPJV, University of Artois, ULCO, 59000 Lille, France
| | - Justine Jacquin
- Joint Research Unit 1158 BioEcoAgro, INRAE, University of Lille, JUNIA, University of Liège, UPJV, University of Artois, ULCO, 59000 Lille, France
| | - Jennifer Samaillie
- Joint Research Unit 1158 BioEcoAgro, INRAE, University of Lille, JUNIA, University of Liège, UPJV, University of Artois, ULCO, 59000 Lille, France
| | - Caroline Deweer
- Joint Research Unit 1158 BioEcoAgro, INRAE, University of Lille, JUNIA, University of Liège, UPJV, University of Artois, ULCO, 59000 Lille, France
| | - Céline Rivière
- Joint Research Unit 1158 BioEcoAgro, INRAE, University of Lille, JUNIA, University of Liège, UPJV, University of Artois, ULCO, 59000 Lille, France
| | - Jérôme Muchembled
- Joint Research Unit 1158 BioEcoAgro, INRAE, University of Lille, JUNIA, University of Liège, UPJV, University of Artois, ULCO, 59000 Lille, France
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Beckerman J, Palmer C, Tedford E, Ypema H. Fifty Years of Fungicide Development, Deployment, and Future Use. PHYTOPATHOLOGY 2023; 113:694-706. [PMID: 37137816 DOI: 10.1094/phyto-10-22-0399-ia] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Plant disease management has not significantly changed significantly in the past 50 years, even as great strides have been made in the understanding of fungal biology and the etiology of plant disease. Issues of climate change, supply chain failures, war, political instability, and exotic invasives have created even more serious implications for world food and fiber security, and the stability of managed ecosystems, underscoring the urgency for reducing plant disease-related losses. Fungicides serve as the primary example of successful, widespread technology transfer, playing a central role in crop protection, reducing losses to both yield and postharvest spoilage. The crop protection industry has continued to improve upon previous fungicide chemistries, replacing active ingredients lost to resistance and newly understood environmental and human health risks, under an increasingly stricter regulatory environment. Despite decades of advances, plant disease management continues to be a constant challenge that will require an integrated approach, and fungicides will continue to be an essential part of this effort.
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Affiliation(s)
- J Beckerman
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
| | - C Palmer
- IR-4 Project, Plant Biology and Pathology, Rutgers, The State University of New Jersey, Cream Ridge, NJ 08514-9634
| | | | - H Ypema
- UPL Services LLC, Durham, NC 27709
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Li Y, Tang Y, Xue Z, Wang Y, Shi Y, Gao X, Li X, Li G, Li F, Lu L, Miao J, Liu X. Resistance Risk and Resistance-Related Point Mutation in SdhB and SdhC 1 of Cyclobutrifluram in Fusarium pseudograminearum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:1886-1895. [PMID: 36657474 DOI: 10.1021/acs.jafc.2c08022] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Cyclobutrifluram is a novel succinate dehydrogenase inhibitor (SDHI) developed by Syngenta and helps to inhibit Fusarium pseudograminearum. Here, the potential for cyclobutrifluram resistance in F. pseudograminearum and the resistance mechanism involved were evaluated. Baseline sensitivity of F. pseudograminearum to cyclobutrifluram was determined with a mean EC50 value of 0.0248 μg/mL. Fungicide adaption generated five resistant mutants, which possess a comparable or a slightly impaired fitness compared to corresponding parental isolates. This indicates that the resistance risk of F. pseudograminearum to cyclobutrifluram might be moderate. Cyclobutrifluram-resistant isolates also demonstrated resistance to pydiflumetofen but sensitivity to carbendazim, phenamacril, tebuconazole, fludioxonil, or pyraclostrobin. Additionally, point mutations H248Y in FpSdhB and A83V or R86K in FpSdhC1 were found in cyclobutrifluram-resistant F. pseudograminearum mutants. Molecular docking and overexpression transformation assay revealed that FpSdhBH248Y and FpSdhC1A83V or FpSdhC1R86K confer the resistance of F. pseudograminearum to cyclobutrifluram.
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Affiliation(s)
- Yiwen Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Yidong Tang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Ziwei Xue
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Yan Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Yifei Shi
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Xuheng Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Xiong Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Guixiang Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Feng Li
- Syngenta (China) Investment Co., Ltd., 567 Bocheng Road, Shanghai200120, China
| | - Liang Lu
- Syngenta (China) Investment Co., Ltd., 567 Bocheng Road, Shanghai200120, China
| | - Jianqiang Miao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
| | - Xili Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, 3 Taicheng Road, Yangling712100, ShaanxiChina
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, 2 Yuanmingyuanxi Road, Beijing100193, China
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Nasonov AI, Yakuba GV, Astapchuk IL. Sensitivity of Krasnodar Venturia inaequalis Populations to the Sterol Demethylation Inhibitor Difenoconazole. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2022; 507:463-472. [PMID: 36781541 DOI: 10.1134/s001249662206014x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 02/15/2023]
Abstract
Difenoconazole sensitivity was assessed in three populations of the apple scab agent Venturia inaequalis of the Krasnodar region. One of the populations was fungicide naïve population; its sample was collected in natural habitats of the eastern crabapple Malus orientalis in foothills of the Severskii raion. The two other populations were from commercial orchards of the apple variety Reinette Simirenko (the Krasnoarmeiskii and Dinskoi raions), where fungicide treatments with various agents, including those with difenoconazole as an active ingredient, were performed on a regular basis. Single-spore V. inaequalis isolates were isolated from fresh leaves with signs of the disease or fallen leaves with fungal fruiting bodies. The median effective concentration (EC50) was defined as the concentration that halves the colony growth and was estimated in a series of in vitro experiments with 120 isolates. Difenoconazole (Score EC, 250 mg/L, Syngenta) was used at six concentrations: 0.005, 0.01, 0.025, 0.05, 0.5, and 1 mg a.i./L. Mean EC50 values were 0.0078 mg a.i./L in the natural population and 0.12 and 0.25 mg a.i./L in the orchard populations. Fungicide sensitivity was lower in both of the orchard populations; their resistance factors were estimated at 16 and 32. The proportion of sensitive and low-sensitive isolates differed between the two orchard populations. A discriminatory dose, or single-assessment concentration (SAC), of 0.01 mg a.i./L was proposed to simplify the laboratory monitoring of the difenoconazole sensitivity in V. inaequalis by using a test for relative growth (RG) of the mycelium. Comparable results were obtained with EC50 and RG at the discriminatory dose. The portion of isolates with RGs exceeding the threshold (RG > 70%) was 97% in one of the orchard populations. The results indicate that difenoconazole resistance develops in V. inaequalis populations from commercial orchards of the Krasnodar region.
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Affiliation(s)
- A I Nasonov
- North Caucasian Federal Research Center of Horticulture, Viniculture, and Wine Industry, Krasnodar, Russia.
| | - G V Yakuba
- North Caucasian Federal Research Center of Horticulture, Viniculture, and Wine Industry, Krasnodar, Russia.
| | - I L Astapchuk
- North Caucasian Federal Research Center of Horticulture, Viniculture, and Wine Industry, Krasnodar, Russia.
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Detection of Venturia inaequalis Isolates with Multiple Resistance in Greece. Microorganisms 2022; 10:microorganisms10122354. [PMID: 36557607 PMCID: PMC9780820 DOI: 10.3390/microorganisms10122354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/30/2022] Open
Abstract
The excessive use of fungicides against Venturia inaequalis, the causal agent of apple scab, has led to the emergence of resistant populations to multiple fungicides over the years. In Greece, there is no available information on fungicide resistance, despite the fact that control failures have been reported on certain areas. An amount of 418 single-spore isolates were collected from three major apple production areas and tested for their sensitivity to eight commonly used fungicides from unrelated chemical groups. The isolates were tested on malt extract agar media enriched with the discriminatory dose of each fungicide using the point inoculation method. To define the discriminatory dose for assessing the levels of resistance, EC50 values on both spore germination and mycelial growth assays were previously determined. Isolates exhibiting high resistance to trifloxystrobin (92% in total) and difenoconazole (3%); and moderate resistance to cyprodinil (75%), dodine (28%), difenoconazole (36%), boscalid (5%), and fludioxonil (7%) were found for the first time in Greece. A small percentage of the isolates were also found less sensitive to captan (8%) and dithianon (6%). Two isolates showed various levels of resistance to all eight fungicides. Despite the occurrence of strains with multiple resistances to many fungicides, we concluded that this practical resistance in the field arose mainly due to the poor control of apple scab with trifloxystrobin and difenoconazole.
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Gleason J, Peng J, Proffer TJ, Slack SM, Outwater CA, Rothwell NL, Sundin GW. Resistance to Boscalid, Fluopyram and Fluxapyroxad in Blumeriella jaapii from Michigan (U.S.A.): Molecular Characterization and Assessment of Practical Resistance in Commercial Cherry Orchards. Microorganisms 2021; 9:microorganisms9112198. [PMID: 34835322 PMCID: PMC8621041 DOI: 10.3390/microorganisms9112198] [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: 09/21/2021] [Revised: 10/15/2021] [Accepted: 10/17/2021] [Indexed: 11/16/2022] Open
Abstract
Management of cherry leaf spot disease, caused by the fungus Blumeriella jaapii, with succinate dehydrogenase inhibitor (SDHI) fungicides has been ongoing in Michigan tart cherry orchards for the past 17 years. After boscalid-resistant B. jaapii were first isolated from commercial orchards in 2010, premixes of SDHI fungicides fluopyram or fluxapyroxad with a quinone outside inhibitor were registered in 2012. Here, we report widespread resistance to fluopyram (FluoR), fluxapyroxad (FluxR), and boscalid (BoscR) in commercial orchard populations of B. jaapii in Michigan from surveys conducted between 2016 and 2019. A total of 26% of 1610 isolates from the 2016-2017 surveys exhibited the fully-resistant BoscR FluoR FluxR phenotype and only 7% were sensitive to all three SDHIs. Practical resistance to fluopyram and fluxapyroxad was detected in 29 of 35 and 14 of 35 commercial tart cherry orchards, respectively, in surveys conducted in 2018 and 2019. Sequencing of the SdhB, SdhC, and SdhD target genes from 22 isolates with varying resistance phenotypes showed that BoscS FluoR FluxS isolates harbored either an I262V substitution in SdhB or an S84L substitution in SdhC. BoscR FluoR FluxR isolates harbored an N86S substitution in SdhC, or contained the N86S substitution with the additional I262V substitution in SdhB. One BoscR FluoR FluxR isolate contained both the I262V substitution in SdhB and the S84L substitution in SdhC. These mutational analyses suggest that BoscR FluoR FluxR isolates evolved from fully sensitive BoscS, FluoS, FluxS isolates in the population and not from boscalid-resistant isolates that were prevalent in the 2010-2012 time period.
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Affiliation(s)
- Jacqueline Gleason
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, E. Lansing, MI 48824, USA; (J.G.); (J.P.); (T.J.P.); (S.M.S.); (C.A.O.)
| | - Jingyu Peng
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, E. Lansing, MI 48824, USA; (J.G.); (J.P.); (T.J.P.); (S.M.S.); (C.A.O.)
| | - Tyre J. Proffer
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, E. Lansing, MI 48824, USA; (J.G.); (J.P.); (T.J.P.); (S.M.S.); (C.A.O.)
| | - Suzanne M. Slack
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, E. Lansing, MI 48824, USA; (J.G.); (J.P.); (T.J.P.); (S.M.S.); (C.A.O.)
| | - Cory A. Outwater
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, E. Lansing, MI 48824, USA; (J.G.); (J.P.); (T.J.P.); (S.M.S.); (C.A.O.)
| | - Nikki L. Rothwell
- Northwest Michigan Horticultural Research Center, Traverse City, MI 49684, USA;
| | - George W. Sundin
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, E. Lansing, MI 48824, USA; (J.G.); (J.P.); (T.J.P.); (S.M.S.); (C.A.O.)
- Correspondence:
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Bezerra GDA, Chaibub AA, Oliveira MIDS, Mizubuti ESG, Filippi MCCD. Evidence of Pyricularia oryzae adaptability to tricyclazole. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2021; 56:869-876. [PMID: 34459365 DOI: 10.1080/03601234.2021.1971913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Pyricularia oryzae is the etiological agent of rice blast, the most destructive disease in rice crops and chemical control based on fungicide is the main method used in its management. The aim of this study was characterize pathogenicity and identify P. oryzae isolates adapted to tricyclazole. P. oryzae monosporic isolates were collected in the state of Tocantins and inoculated in international differentiating series of rice cultivars for determination of pathotypes. After, the same isolates were inoculated in the rice cultivar IRGA 424 to evaluate resistance to fungicide Bim® 750 BR (Tricyclazole - 250 g/ha) that was applied 24 and 48 hours after pathogen inoculation (hai). Leaf blast severity and infection efficiency were evaluated 9 days after inoculation (dai), latency period (2 dai) and sporulation intensity (7 dai). Nine different pathotypes were identified, predominantly as IA group. The latent period of isolates occurred between from 48 to 120 h. The application of tricyclazole, 24 hai reduced disease severity with the exception of the isolate Py 7.1. The great variability of the pathogen allowed for adaptation to this molecule and can increase its aggressiveness and should be considered to guide the integrated management of the disease.
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Affiliation(s)
| | | | | | - Eduardo Seiti Gomide Mizubuti
- Phytopathogen Population Biology Laboratory - BioPop, Department of Phytopathology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
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Cordero-Limon L, Shaw MW, Passey TA, Robinson JD, Xu X. Cross-resistance between myclobutanil and tebuconazole and the genetic basis of tebuconazole resistance in Venturia inaequalis. PEST MANAGEMENT SCIENCE 2021; 77:844-850. [PMID: 32926586 DOI: 10.1002/ps.6088] [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] [Received: 04/02/2020] [Revised: 07/05/2020] [Accepted: 09/14/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Myclobutanil is one of the most widely used demethylation inhibitor (DMI) fungicides for the management of apple scab, caused by Venturia inaequalis. Strains of V. inaequalis resistant to myclobutanil have been reported across the world. Tebuconazole, another DMI fungicide, has been proposed as an alternative to myclobutanil, and the extent of cross-resistance with myclobutanil therefore needs to be evaluated. The sensitivity to tebuconazole and myclobutanil of a total of 40 isolates was determined. Half the isolates came from an isolated orchard which had never been sprayed with fungicides and half from orchards sprayed regularly with myclobutanil, but still with disease control problems. The progeny of a tebuconazole resistant (R) × sensitive (S) V. inaequalis cross were analyzed in order to improve understanding of the genetic control of tebuconazole sensitivity. RESULTS There is cross-resistance between myclobutanil and tebuconazole (r = 0.91; P < 0.001). Sensitivity to tebuconazole of the progeny of a R × S cross varied quantitatively in a pattern which implied at least two gene loci differing between the parental strains. In addition, the asymmetric distribution of the sensitivity in the progeny implied possible epistatic effects. CONCLUSION Resistance to myclobutanil and tebuconazole is strongly correlated. At least two genes are involved in the control of tebuconazole resistance in V. inaequalis.
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Affiliation(s)
- Laura Cordero-Limon
- School of Agriculture, Policy and Development, University of Reading, Reading, UK
- NIAB EMR, Kent, UK
| | - Michael W Shaw
- School of Agriculture, Policy and Development, University of Reading, Reading, UK
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Grishechkina L, Podgornaya M, Dolzhenko V. Difenoconazole-based fungicides for orchard protection. BIO WEB OF CONFERENCES 2021. [DOI: 10.1051/bioconf/20213404004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A comparative assessment of the effectiveness of 4 difenoconazole-based fungicides in the fight against apple scab in the Krasnodar region and the Rostov Region for several years has been carried out. The preparations Sercadis Plus, SC were applicated at a rate of application of 1.2 l/ha; Embrelia, SC – 1.5 l/ha; Cidely Top, DС – 0.7 l/ha and Tersel, WG – 2.5 kg/ha three times, against different infectious backgrounds, starting with the “pink bud” phenophase (the end of flowering stage). The following apple cultivars were used: Idared, Champion and Golden Delicious. Research has shown that all studied fungicides significantly reduced the scab infestation of apple leaves and fruits. This resulted in obtaining additional yield in the range of 12.6-46.0%. The fruit grade was high after the treatments: 93.0-100% in the Krasnodar region and 81.5-91.5% in the Rostov Region, while in the nil treatment the percentages of standard products were 68.5% and 44.6%, respectively. According to the toxic load indicator, difenoconazole-based fungicides, such as Embrelia, SC (11.6 LD50 per hectare), were less dangerous for the fruit cenosis.
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15
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Patocchi A, Wehrli A, Dubuis PH, Auwerkerken A, Leida C, Cipriani G, Passey T, Staples M, Didelot F, Philion V, Peil A, Laszakovits H, Rühmer T, Boeck K, Baniulis D, Strasser K, Vávra R, Guerra W, Masny S, Ruess F, Le Berre F, Nybom H, Tartarini S, Spornberger A, Pikunova A, Bus VGM. Ten Years of VINQUEST: First Insight for Breeding New Apple Cultivars With Durable Apple Scab Resistance. PLANT DISEASE 2020; 104:2074-2081. [PMID: 32525450 DOI: 10.1094/pdis-11-19-2473-sr] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Apple scab, caused by Venturia inaequalis, is a major fungal disease worldwide. Cultivation of scab-resistant cultivars would reduce the chemical footprint of apple production. However, new apple cultivars carrying durable resistances should be developed to prevent or at least slow the breakdown of resistance against races of V. inaequalis. One way to achieve durable resistance is to pyramid multiple scab resistance genes in a cultivar. The choice of the resistance genes to be combined in the pyramids should take into account the frequency of resistance breakdown and the geographical distribution of apple scab isolates able to cause such breakdowns. In order to acquire this information and to make it available to apple breeders, the VINQUEST project (www.vinquest.ch) was initiated in 2009. Ten years after launching this project, 24 partners from 14 countries regularly contribute data. From 2009 to 2018, nearly 9,000 data points have been collected. This information has been used to identify the most promising apple scab resistance genes for developing cultivars with durable resistance, which to date are: Rvi5, Rvi11, Rvi12, Rvi14, and Rvi15. As expected, Rvi1, together with Rvi3 and Rvi8, were often overcome, and have little value for scab resistance breeding. Rvi10 may also belong to this group. On the other hand, Rvi2, Rvi4, Rvi6, Rvi7, Rvi9, and Rvi13 are still useful for breeding, but their use is recommended only in extended pyramids of ≥3 resistance genes.
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Affiliation(s)
| | - Andreas Wehrli
- Agroscope, Breeding Research, 8820 Wädenswil, Switzerland
| | | | | | - Carmen Leida
- Consorzio Italiano Vivaisti CIV, 44022 San Giuseppe di Comacchio, Italy
| | - Guido Cipriani
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, University of Udine, 33100 Udine, Italy
| | - Tom Passey
- NIAB EMR, East Malling, West Malling ME19 6BJ, United Kingdom
| | - Martina Staples
- Höhere Bundeslehranstalt und Bundesamt für Wein- und Obstbau Klosterneuburg, 3400 Klosterneuburg, Austria
| | - Frédérique Didelot
- IRHS, Agrocampus-Ouest, INRA, Université d'Angers, 49071 Beaucouzé, France
| | - Vincent Philion
- Institut de Recherche et de Développement en Agroenvironnement, Saint-Bruno-de-Montarville, QC J3V 0G7, Canada
| | - Andreas Peil
- Julius Kühn-Institut (JKI), Bundesforschungsinstitut für Kulturpflanzen, Institut für Züchtungsforschung an Obst, 01326 Dresden, Germany
| | | | - Thomas Rühmer
- Versuchsstation Obst- und Weinbau Haidegg, 8047 Graz, Austria
| | - Klemens Boeck
- Landwirtschaftskammer Tirol, 6020 Innsbruck, Austria
| | - Danas Baniulis
- Lithuanian Research Centre for Agriculture and Forestry, 54333 Babtai, Lithuania
| | | | - Radek Vávra
- Research and Breeding Institute of Pomology, Holovousy 129, 508 01 Horice, Czech Republic
| | - Walter Guerra
- Laimburg Research Centre, Laimburg 6, 39040 Ora, Italy
| | | | - Franz Ruess
- Staatliche Lehr- und Versuchsanstalt für Wein und Obstbau Weinsberg, 74189 Weinsberg, Germany
| | - Fanny Le Berre
- Station d'études et d'expérimentations fruitières de La Morinière, La Morinière, 37800 Saint Epain, France
| | - Hilde Nybom
- Swedish University of Agricultural Sciences, Balsgård, 29194 Kristianstad, Sweden
| | - Stefano Tartarini
- Department of Agricultural and Food Sciences, University of Bologna, 40126 Bologna, Italy
| | | | - Anna Pikunova
- VNIISPK - Russian Research Institute of Fruit Crop Breeding, 302530 Zilina, Russia
| | - Vincent G M Bus
- The New Zealand Institute for Plant and Food Research Limited, 4157 Havelock North, New Zealand
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16
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Wang Z, Peng Q, Hou Y, Gao X, Zhong S, Fang Y, Liu C, Liu X. Resistance assessment for SYP-14288 in Phytophthora capsici and changes in mitochondria electric potential-associated respiration and ATP production confers resistance. PEST MANAGEMENT SCIENCE 2020; 76:2525-2536. [PMID: 32077584 DOI: 10.1002/ps.5795] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/08/2020] [Accepted: 02/20/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Phytophthora capsici is a destructive plant oomycete pathogen that could lead to devastating losses in food production. Fungicide application is the main way to control plant disease caused by P. capsici. SYP-14288, a novel fungicide with a unique mode of action, could be used to control a broad range of plant diseases. Here, the potential for SYP-14288 resistance in P. capsici and the resistance mechanism involved were evaluated. RESULTS Baseline sensitivities of 133 isolates to SYP-14288 were determined and found to conform to a unimodal curve with a mean half-maximal effective concentration (EC50 ) of 0.625 μg mL-1 . In total, 21 stable SYP-14288-resistant mutants were generated by fungicide adaptation in three sensitive isolates. The fitness of all the mutants was found to be lower than that of the parental isolates. Otherwise, downregulation of various ATPases may confer different resistance levels in P. capsici. Finally, multiple biochemical studies strongly suggest that both ATP content and electric potential were reduced in SYP-14288-resistant mutants, and as a compensatory mechanism, respiration was facilitated to make up for the energy defect in mutants. CONCLUSION The low fitness of SYP-14288-resistant mutants suggests that the resistance risk of P. capsici to SYP-14288 is low. Resistance may be led by a permeability change in the mitochondrial inner membrane in SYP-14288-resistant isolates, and lower ATP consumption lifestyles may be key to the SYP-14288 resistance generated in P. capsici. The current study could benefit the registration and application of the novel fungicide SYP-14288. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Zhiwen Wang
- China Agricultural University, Beijing, China
| | - Qin Peng
- China Agricultural University, Beijing, China
| | - Yanhua Hou
- China Agricultural University, Beijing, China
| | - Xiang Gao
- China Agricultural University, Beijing, China
| | - Shan Zhong
- China Agricultural University, Beijing, China
| | - Yuan Fang
- China Agricultural University, Beijing, China
| | - Changling Liu
- State Key Laboratory of Discovery and Development of Novel Pesticide, China Shenyang Research Institute of Chemical Industry, Shenyang, China
| | - Xili Liu
- College of Plant Protection, Northwest A&F University, Yangling, China
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17
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Yang X, Chen X, Song Z, Zhang X, Zhang J, Mei S. Antifungal, plant growth-promoting, and mycotoxin detoxication activities of Burkholderia sp. strain XHY-12. 3 Biotech 2020; 10:158. [PMID: 32181120 PMCID: PMC7056774 DOI: 10.1007/s13205-020-2112-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 02/02/2020] [Indexed: 01/16/2023] Open
Abstract
A bacterial strain named XHY-12 was isolated from corn soil samples and identified as Burkholderia sp. based on 16S rDNA sequencing, it displayed high antagonistic activity against 12 fungal pathogens and the common fungal contaminant in grain Aspergillus flavus. Plate experiment showed that XHY-12 fermentation broth reduced the incidence of S. sclerotiorum on detached rape leaves (Brassica campestris L.) by 100%, and a greenhouse experiment showed that it could promote the growth of rape seedlings with significant increases in plant height, root length, and fresh weight. Furthermore, a novel funding was the reduction of aflatoxin B1 and B2 by over 85% in 60 h, and the decomposition enzymes should be extracellular. The results suggest that XHY-12 has a potential for commercial applications as biocontrol, mycotoxin detoxification agent or biofertilizer.
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Affiliation(s)
- Xiai Yang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348# of West Road of Xianjia Lake, Changsha City, Hunan Province China
| | - Xiaojun Chen
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348# of West Road of Xianjia Lake, Changsha City, Hunan Province China
| | - Zhiqiang Song
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348# of West Road of Xianjia Lake, Changsha City, Hunan Province China
| | - Xiaowei Zhang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348# of West Road of Xianjia Lake, Changsha City, Hunan Province China
| | - Jifang Zhang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348# of West Road of Xianjia Lake, Changsha City, Hunan Province China
| | - Shiyong Mei
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348# of West Road of Xianjia Lake, Changsha City, Hunan Province China
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18
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Papp D, Singh J, Gadoury D, Khan A. New North American Isolates of Venturia inaequalis Can Overcome Apple Scab Resistance of Malus floribunda 821. PLANT DISEASE 2020; 104:649-655. [PMID: 31961770 DOI: 10.1094/pdis-10-19-2082-re] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Apple scab, caused by Venturia inaequalis, is a destructive fungal disease of major apple cultivars worldwide, most of which are moderately to highly susceptible. Thus, development of scab resistant cultivars is one of the highest priorities of apple breeding programs. The principal source of resistance for breeding programs has been the scab resistance gene Rvi6 that originated from the Japanese crabapple Malus floribunda (Sieb.) sel. 821. Isolates of V. inaequalis able to overcome Rvi6 have been identified in Europe, but have not yet been reported on the American continents. We recently discovered scab infection on M. floribunda 821 trees in a research orchard at Geneva, NY, U.S.A., where approximately 10% of the leaves bore profusely sporulating apple scab lesions, many of which had coalesced to cover entire leaves. We observed both chlorosis, typical to Rvi6, and pinpoint pitting symptoms typical to failed infections by V. inaequalis on hosts bearing the Rvi7 gene. We assessed genetic diversity and population genetic structure of 11 V. inaequalis isolates in total, of North American and European origin, isolated from M. floribunda 821, 'Nova Easygro', 'Golden Delicious', TSR33T239, 'Schone van Boskoop', and 'Prima', using 16,321 genome-wide SNPs. Population genetic structure and PCA separated the isolates into distinct European and U.S. groups. The forgoing suggests that the new Rvi6 virulent isolates emerged within U.S. populations, rather than being transported from Europe. The complete resistance breakdown in M. floribunda 821 but not in descendant cultivars, which kept their field resistance, suggests that durable resistance to apple scab will require a more comprehensive understanding of Rvi6 mediated resistance in diverse genetic backgrounds.
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Affiliation(s)
- David Papp
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, NY 14456, U.S.A
| | - Jugpreet Singh
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, NY 14456, U.S.A
| | - David Gadoury
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, NY 14456, U.S.A
| | - Awais Khan
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, NY 14456, U.S.A
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19
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Ayer KM, Villani SM, Choi MW, Cox KD. Characterization of the VisdhC and VisdhD Genes in Venturia inaequalis, and Sensitivity to Fluxapyroxad, Pydiflumetofen, Inpyrfluxam, and Benzovindiflupyr. PLANT DISEASE 2019; 103:1092-1100. [PMID: 31012823 DOI: 10.1094/pdis-07-18-1225-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Succinate dehydrogenase inhibitors (SDHI) are an important class of fungicides for management of apple scab, especially as resistance to other classes of fungicides has become prevalent in the northeastern United States. Considering their single-site mode of action, there is high risk of resistance development to SDHI fungicides. Such risk mandates the need for proper monitoring of shifts in population sensitivity. This study aims to provide a means for phenotypic and genotypic characterization of SDHI fungicide resistance for Venturia inaequalis, the causal agent of apple scab. To complement the published sequence of VisdhB, target genes VisdhC and VisdhD were identified using sequences of homologous genes in other fungal organisms and a draft genome of V. inaequalis. Using mycelial growth and conidial germination assays, baseline sensitivities and cross sensitivities of V. inaequalis were determined for several SDHI fungicides. Mean baseline EC50 values for conidial germination of benzovindiflupyr, fluxapyroxad, pydiflumetofen, and inpyrfluxam were found to be 0.0021, 0.0284, 0.014, and 0.0137 μg ml-1, respectively. Mean baseline EC50 values for mycelial growth of benzovindiflupyr, fluxapyroxad, pydiflumetofen, and inpyrfluxam were found to be 0.0575, 0.228, 0.062, and 0.0291 μg ml-1, respectively. A significant and positive correlation in sensitivity was found between benzovindiflupyr, fluxapyroxad, pydiflumetofen, and inpyrfluxam as well as penthiopyrad and fluopyram, with the highest correlation between benzovindiflupyr and penthiopyrad for mycelial inhibition of V. inaequalis (r = 0.950, P < 0.001). For inhibition of conidial germination, the highest correlation was observed between penthiopyrad and fluopyram (r = 0.775, P < 0.001). Furthermore, the sequences of the VisdhC and VisdhD genes were identified and characterized for baseline isolates of V. inaequalis. Residues of similar position to mutations found in other systems that confer resistance to SDHI fungicides were identified in baseline isolates, but no mutations were identified in baseline isolates or those previously exposed to SDHI fungicides. This study will serve as a reference for future monitoring of resistance to SDHI fungicides in V. inaequalis at both a phenotypic and genotypic level.
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Affiliation(s)
- Katrin M Ayer
- 1 Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Geneva, NY 14456; and
| | - Sara M Villani
- 2 Department of Entomology and Plant Pathology, Mountain Horticultural Crops Research and Extension Center, North Carolina State University, Mills River, NC 28759
| | - Mei-Wah Choi
- 1 Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Geneva, NY 14456; and
| | - Kerik D Cox
- 1 Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Geneva, NY 14456; and
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20
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Beckerman J, Abbott C. Comparative Studies on the Effect of Adjuvants with Urea to Reduce the Overwintering Inoculum of Venturia inaequalis. PLANT DISEASE 2019; 103:531-537. [PMID: 30652961 DOI: 10.1094/pdis-06-18-1014-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A 2-year study on the use of organic and conventional adjuvants alone, or mixed with urea, was conducted for management of overwintering inoculum of the apple scab pathogen, Venturia inaequalis. Select adjuvants (LI 700, Bond Max, Latron B-1956, and Organic Wet Betty [OWB]) have the potential to hasten urea-driven leaf litter decomposition and reduce V. inaequalis overwintering inoculum comparable to urea, and that one organic surfactant could perform the same level of leaf decomposition as urea. Combinations of adjuvants with urea significantly improved leaf litter degradation compared with urea alone, concomitant with reducing the number of pseudothecia present and pseudothecium fertility. We demonstrate that the combination of urea with Bond Max or OWB reduced pseudothecia fertility and ascospore production to less than 5% in the remaining pseudothecia, a significantly greater reduction than with urea alone. These results suggest that conventional growers combine urea with Bond Max or OWB to more effectively reduce overwintering inoculum, and that the adjuvant OWB can provide organic growers with comparable performance to urea used in conventional orchards for improved sanitation.
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Affiliation(s)
- Janna Beckerman
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
| | - Chelsi Abbott
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
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21
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Development of a high throughput optical density assay to determine fungicide sensitivity of oomycetes. J Microbiol Methods 2018; 154:33-39. [DOI: 10.1016/j.mimet.2018.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 09/26/2018] [Accepted: 10/08/2018] [Indexed: 12/11/2022]
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22
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Hawkins NJ, Fraaije BA. Fitness Penalties in the Evolution of Fungicide Resistance. ANNUAL REVIEW OF PHYTOPATHOLOGY 2018; 56:339-360. [PMID: 29958074 DOI: 10.1146/annurev-phyto-080417-050012] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The evolution of resistance poses an ongoing threat to crop protection. Fungicide resistance provides a selective advantage under fungicide selection, but resistance-conferring mutations may also result in fitness penalties, resulting in an evolutionary trade-off. These penalties may result from the functional constraints of an evolving target site or from the resource allocation costs of overexpression or active transport. The extent to which such fitness penalties are present has important implications for resistance management strategies, determining whether resistance persists or declines between treatments, and for resistance risk assessments for new modes of action. Experimental results have proven variable, depending on factors such as temperature, nutrient status, osmotic or oxidative stress, and pathogen life-cycle stage. Functional genetics tools allow pathogen genetic background to be controlled, but this in turn raises the question of epistatic interactions. Combining fitness penalties under various conditions into a field-realistic scenario poses an important future challenge.
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Affiliation(s)
- N J Hawkins
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom;
| | - B A Fraaije
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom;
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Porsche FM, Molitor D, Beyer M, Charton S, André C, Kollar A. Antifungal Activity of Saponins from the Fruit Pericarp of Sapindus mukorossi against Venturia inaequalis and Botrytis cinerea. PLANT DISEASE 2018; 102:991-1000. [PMID: 30673376 DOI: 10.1094/pdis-06-17-0906-re] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The antifungal activity of an aqueous extract (AE) and the solid fraction of a chloroform-methanol fruit pericarp extract (CME) of Sapindus mukorossi resolved in water was tested for the first time against Venturia inaequalis and Botrytis cinerea-two important fungal pathogens worldwide. In the greenhouse, a CME (1% vol/vol) spray significantly reduced V. inaequalis symptoms and sporulation (99%) on apple seedling leaves (P ≤ 0.05). In field trials, applications of AE (1% vol/vol) reduced the disease severity of B. cinerea on grape, on average, by 63%. Extracts were fractionated by high-performance liquid chromatography and the bioefficacy of the fractions was tested in vitro. Some components of the most fungicidal fraction were identified by liquid chromatography-high resolution mass spectrometry as saponins: sapindoside B (accounting for ≥98% of the total constituents), hederagenin-pentosylhexoside, and oleanolic acid-hexosyl-deoxyhexosyl-hexoside. This fraction inhibited the mycelial growth of V. inaequalis and B. cinerea by 45 and 43%, respectively.
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Affiliation(s)
- Franziska M Porsche
- Julius Kühn-Institute, Federal Research Center for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture, 69221 Dossenheim, Germany
| | - Daniel Molitor
- Luxembourg Institute of Science and Technology, Environmental Research and Innovation Department, 4422 Belvaux, Luxembourg
| | - Marco Beyer
- Luxembourg Institute of Science and Technology, Environmental Research and Innovation Department, 4422 Belvaux, Luxembourg
| | - Sophie Charton
- Luxembourg Institute of Science and Technology, Environmental Research and Innovation Department, 4422 Belvaux, Luxembourg
| | - Christelle André
- Luxembourg Institute of Science and Technology, Environmental Research and Innovation Department, 4422 Belvaux, Luxembourg
| | - Andreas Kollar
- Julius Kühn-Institute, Federal Research Center for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture
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Abbott CP, Beckerman JL. Incorporating Adjuvants with Captan to Manage Common Apple Diseases. PLANT DISEASE 2018; 102:231-236. [PMID: 30673455 DOI: 10.1094/pdis-05-17-0629-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Captan has become an increasingly important fungicide in the management of common apple diseases such as apple scab (Venturia inaequalis) and bitter rot (Colletotrichum spp.) due to the low risk of fungicide resistance evolving in either pathogen population to this product. Restrictions on the amount of captan that can be applied per season limits the amount and the number of applications a grower may use, resulting in control failures during high disease pressure years. This 3-year field study evaluated how adjuvants combined with captan affected the incidence and severity of apple scab and bitter rot on two different apple cultivars. Results showed that Li700 plus captan and Bond Max plus captan reduced disease incidence of apple scab and bitter rot in years with moderate to high disease pressure by increasing the coverage and retention of captan. The addition of these adjuvants also resulted in possible yield losses due to russetting caused by phytotoxicity. The overall benefits of incorporating adjuvants with captan based on this study could reduce disease incidence while potentially saving a grower up to $5,329 ha-1 due to fungicide reduction.
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Affiliation(s)
- Chelsi P Abbott
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
| | - Janna L Beckerman
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
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25
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Porsche FM, Pfeiffer B, Kollar A. A New Phytosanitary Method to Reduce the Ascospore Potential of Venturia inaequalis. PLANT DISEASE 2017; 101:414-420. [PMID: 30677339 DOI: 10.1094/pdis-07-16-0994-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Ascospores of Venturia inaequalis, released from pseudothecia in overwintered, infected apple leaves, serve as the primary inoculum for apple scab. In this study, we tested a new sanitation strategy to reduce ascospore inoculum under orchard conditions over three overwintering periods. After leaf fall, nutrient media containing different concentrations of degraded casein or a yeast extract from Saccharomyces cerivisiae were applied to leaf litter infected with apple scab. The application of 30 and 60% yeast extract showed the greatest efficacy, and significantly reduced ascospore discharge by 99% (P < 0.01) in 2013 and 2014. The efficacy of the treatments did not differ from treatment with 5% urea (P > 0.05). Leaf litter decay was accelerated in the plots treated with yeast extract compared with untreated control plots. Moreover, apple leaves treated with yeast extract had completely decayed due to earthworm activity before ascospore maturity. In comparison, up to 26% of the leaves in untreated control plots had not decayed. These results suggest that the treatment of leaf litter with yeast extract can almost completely eliminate apple scab inoculum in the course of the whole primary season. These sanitation practices may be beneficial for both organic and conventional cultivation. The reduced infection pressure may allow growers the usage of fungicides with lower efficacy or to reduce the number of applications needed to manage apple scab in spring.
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Affiliation(s)
- Franziska M Porsche
- Julius Kühn-Institute, Federal Research Center for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture, 69221 Dossenheim, Germany
| | - Barbara Pfeiffer
- State Research Institute for Viticulture & Pomiculture, 74189 Weinsberg, Germany
| | - Andreas Kollar
- Julius Kühn-Institute, Federal Research Center for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture
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26
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Lamichhane JR, Dachbrodt-Saaydeh S, Kudsk P, Messéan A. Toward a Reduced Reliance on Conventional Pesticides in European Agriculture. PLANT DISEASE 2016; 100:10-24. [PMID: 30688570 DOI: 10.1094/pdis-05-15-0574-fe] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Whether modern agriculture without conventional pesticides will be possible or not is a matter of debate. The debate is meaningful within the context of rising health and environmental awareness on one hand, and the global challenge of feeding a steadily growing human population on the other. Conventional pesticide use has come under pressure in many countries, and some European Union (EU) Member States have adopted policies for risk reduction following Directive 2009/128/EC, the sustainable use of pesticides. Highly diverse crop production systems across Europe, having varied geographic and climatic conditions, increase the complexity of European crop protection. The economic competitiveness of European agriculture is challenged by the current legislation, which banned the use of many previously authorized pesticides that are still available and applied in other parts of the world. This challenge could place EU agricultural production at a disadvantage, so EU farmers are seeking help from the research community to foster and support integrated pest management (IPM). Ensuring stable crop yields and quality while reducing the reliance on pesticides is a challenge facing the farming community is today. Considering this, we focus on several diverse situations in European agriculture in general and in European crop protection in particular. We emphasize that the marked biophysical and socio-economic differences across Europe have led to a situation where a meaningful reduction in pesticide use can hardly be achieved. Nevertheless, improvements and/or adoption of the knowledge and technologies of IPM can still achieve large gains in pesticide reduction. In this overview, the current pest problems and their integrated management are discussed in the context of specific geographic regions of Europe, with a particular emphasis on reduced pesticide use. We conclude that there are opportunities for reduction in many parts of Europe without significant losses in crop yields.
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Affiliation(s)
| | - Silke Dachbrodt-Saaydeh
- Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Stahnsdorfer Damm 81, 14532 Kleinmachnow, Germany
| | - Per Kudsk
- Aarhus University, Department of Agroecology, Forsoegsvej 1, 4200 Slagelse 14 Denmark
| | - Antoine Messéan
- INRA, UAR 1240 Eco-Innov, BP 01, 78850 Thiverval-Grignon, France
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27
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Fan Z, Yang JH, Fan F, Luo CX, Schnabel G. Fitness and Competitive Ability of Alternaria alternata Field Isolates with Resistance to SDHI, QoI, and MBC Fungicides. PLANT DISEASE 2015; 99:1744-1750. [PMID: 30699523 DOI: 10.1094/pdis-03-15-0354-re] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Field isolates of Alternaria alternata from peach were previously characterized for their sensitivity to succinate dehydrogenase inhibitor (SDHI) fungicides and the underlying molecular basis of resistance was determined. In the present study, we report that isolates resistant to the SDHI fungicide boscalid, regardless of genotype, were also resistant to pyraclostrobin and thiophanate-methyl. Resistance to pyraclostrobin was due to the G143A mutation in cytochrome b and resistance to thiophanate-methyl was due to 167Y in β-tubulin. Representatives of the two most commonly isolated SDHI resistance genotypes, H277Y in sdh subunit B and H134R in sdh subunit C, as well as genotype D123E in sdh subunit D, were selected for fitness evaluations. Genotypes H277Y and H134R suffered no fitness penalties based on mycelial growth on potato dextrose agar, spore production in vitro, osmotic sensitivity, oxidative sensitivity, germination ability, or the ability to cause disease on peach fruit. Hypersensitivity to oxidative stress and weak sporulation was observed only in genotype D123E. No competitive advantage was detected for sensitive isolates over the course of five consecutive transfers on peach fruit when spores were mixed with genotypes H277Y or H134R. Results suggest that, in the absence of fungicide pressure, A. alternata isolates resistant to methyl benzimidazole carbamate, quinone outside inhibitor, and SDHI fungicides carrying the H277Y mutation in SDHB and the H134R mutation in SDHC may effectively compete with the boscalid-sensitive populations.
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Affiliation(s)
- Zhen Fan
- Department of Agricultural and Environmental Sciences, Clemson University, Clemson, SC 29634
| | - Jing-Hui Yang
- Zhenjiang Institute of Agricultural Sciences, Jiangsu, China
| | - Fei Fan
- Department of Plant Protection, College of Plant Science and Technology and the Key Lab of Crop Disease Monitoring and Safety Control in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Chao-Xi Luo
- Department of Plant Protection, College of Plant Science and Technology and the Key Lab of Crop Disease Monitoring and Safety Control in Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Guido Schnabel
- Department of Agricultural and Environmental Sciences, Clemson University
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28
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Villani SM, Biggs AR, Cooley DR, Raes JJ, Cox KD. Prevalence of Myclobutanil Resistance and Difenoconazole Insensitivity in Populations of Venturia inaequalis. PLANT DISEASE 2015; 99:1526-1536. [PMID: 30695968 DOI: 10.1094/pdis-01-15-0002-re] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Demethylation inhibitors (DMIs) are a class of single-site fungicides with high levels of protective and curative efficacy against Venturia inaequalis, the causal agent of apple scab. To determine the prevalence of resistance to the DMI fungicide myclobutanil, 3,987 single-lesion conidial V. inaequalis isolates from 141 commercial, research, and baseline orchard populations were examined throughout New England, the mid-Atlantic, and the Midwest from 2004 to 2013. Of these orchard populations, 63% had practical resistance, 13% had reduced sensitivity, and 24% were sensitive to myclobutanil. A sensitivity baseline for the recently introduced DMI fungicide difenoconazole was established to make comparisons with myclobutanil sensitivity in orchard populations. The mean effective concentration of difenoconazole at which mycelial growth was inhibited by 50% (EC50) was determined to be 0.002 μg ml-1 for 44 baseline isolates of V. inaequalis. From 2010 to 2013, 1,012 isolates of V. inaequalis from 37 of the 141 orchard populations above were screened for sensitivity to difenoconazole. In all, 1 orchard population had reduced sensitivity to difenoconazole, while the remaining 36 orchard populations were sensitive to the fungicide. In field experiments, difenoconazole demonstrated high levels of apple scab control on mature apple fruit, despite the fact that the population of V. inaequalis had practical resistance to difenoconazole. Although our results indicate widespread resistance to myclobutanil but not difenoconazole, due to the propensity for cross-sensitivity among DMI fungicides, growers with myclobutanil resistance should be cautious when using difenoconazole for disease management.
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Affiliation(s)
- Sara M Villani
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University, Geneva, NY 14456
| | - Alan R Biggs
- Kearneysville Tree Fruit Research and Education Center, West Virginia University, Kearneysville 25443
| | - Daniel R Cooley
- Department Plant, Soil, and Insect Science, University of Massachusetts, Amherst 01003
| | - Jessica J Raes
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University
| | - Kerik D Cox
- Section of Plant Pathology and Plant-Microbe Biology, School of Integrative Plant Science, Cornell University
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29
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Price PP, Purvis MA, Cai G, Padgett GB, Robertson CL, Schneider RW, Albu S. Fungicide Resistance in Cercospora kikuchii, a Soybean Pathogen. PLANT DISEASE 2015; 99:1596-1603. [PMID: 30695960 DOI: 10.1094/pdis-07-14-0782-re] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Isolates of Cercospora kikuchii, a soybean (Glycine max) pathogen causing Cercospora leaf blight and purple seed stain, were tested to determine baseline sensitivities (n = 50) to selected quinone outside inhibitor (QoI) fungicides by conducting radial growth assays on fungicide-amended media. Baseline effective fungicide concentration to inhibit 50% of fungal radial growth (EC50) values were compared with EC50 values for isolates collected in 2011 (n = 50), 2012 (n = 50), and 2013 (n = 36) throughout soybean-producing areas in Louisiana. Median EC50 values for isolates subjected to QoI fungicides were significantly (P = 0.05) higher across all 3 years. Cross-resistance to QoI fungicides was observed in resistant isolates collected in 2011 to 2013. Discriminatory doses were developed for QoI fungicides to distinguish between sensitive and resistant isolates. On average, 89% of all isolates screened in 2011 to 2013 were resistant to QoI fungicides. At a discriminatory dose of thiophanate methyl (TM), a methyl benzimidazole carbamate (MBC) fungicide, at 5 μg/ml, resistance was detected in the 2000, 2011, 2012, and 2013 collections at 23, 38, 29, and 36%, respectively. Isolates exhibiting multiple resistance to QoI fungicides and TM also were detected in 2011, 2012, and 2013 at frequencies of 34, 26, and 31%, respectively. Based on these results, Cercospora leaf blight management strategies in Louisiana using solo applications of QoI or MBC fungicides in soybean should be reconsidered.
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Affiliation(s)
- Paul P Price
- Louisiana State University AgCenter, Winnsboro 71295
| | - Myra A Purvis
- Louisiana State University AgCenter, Winnsboro 71295
| | | | - Guy B Padgett
- Louisiana State University AgCenter, Alexandria 71302
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30
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Fernández-Ortuño D, Grabke A, Li X, Schnabel G. Independent Emergence of Resistance to Seven Chemical Classes of Fungicides in Botrytis cinerea. PHYTOPATHOLOGY 2015; 105:424-432. [PMID: 25317841 DOI: 10.1094/phyto-06-14-0161-r] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Gray mold, caused by the fungal pathogen Botrytis cinerea, is one of the most destructive diseases of small fruit crops and control is largely dependent on the application of fungicides. As part of a region-wide resistance-monitoring program that investigated 1,890 B. cinerea isolates from 189 fields in 10 states of the United States, we identified seven isolates (0.4%) from five locations in four different states with unprecedented resistance to all seven Fungicide Resistance Action Committee (FRAC) codes with single-site modes of action including FRAC 1, 2, 7, 9, 11, 12, and 17 registered in the United States for gray mold control. Resistance to thiophanate-methyl, iprodione, boscalid, pyraclostrobin, and fenhexamid was based on target gene mutations that conferred E198A and F200Y in β-tubulin, I365N/S in Bos1, H272R/Y in SdhB, G143A in Cytb, and T63I and F412S in Erg27. Isolates were grouped into MDR1 and MDR1h phenotypes based on sensitivity to fludioxonil and variations in transcription factor mrr1. MDR1h isolates had a previously described 3-bp deletion at position 497 in mrr1. Expression of ABC transporter atrB was increased in MDR1 isolates but highest in MDR1h isolates. None of the isolates with seven single resistances (SR) had identical nucleotide variations in target genes, indicating that they emerged independently. Multifungicide resistance phenotypes did not exhibit significant fitness penalties for the parameters used in this study, but MDR1h isolates produced more sclerotia at low temperatures and exhibited increased sensitivity to salt stress. In this study we show that current resistance management strategies have not been able to prevent the geographically independent development of resistance to all seven site-specific fungicides currently registered for gray mold control in the United States and document the presence of MDR1h in North America.
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Affiliation(s)
- Dolores Fernández-Ortuño
- First, second, third, and fourth authors: School of Agricultural, Forest, & Environmental Sciences, Clemson University, Clemson, SC 29634; and first author: Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Dept. de Microbiología, Campus de Teatinos, 29071 Málaga, Spain
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31
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Caffier V, Patocchi A, Expert P, Bellanger MN, Durel CE, Hilber-Bodmer M, Broggini GAL, Groenwold R, Bus VGM. Virulence Characterization of Venturia inaequalis Reference Isolates on the Differential Set of Malus Hosts. PLANT DISEASE 2015; 99:370-375. [PMID: 30699702 DOI: 10.1094/pdis-07-14-0708-re] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A set of differential hosts has recently been identified for 17 apple scab resistance genes in an updated system for defining gene-for-gene (GfG) relationships in the Venturia inaequalis-Malus pathosystem. However, a set of reference isolates characterized for their complementary avirulence alleles is not yet available. In this paper, we report on improving the set of differential hosts for h(7) and propose the apple genotype LPG3-29 as carrying the single major resistance gene Rvi7. We characterized a reference set of 23 V. inaequalis isolates on 14 differential apple hosts carrying major resistance genes under controlled conditions. We identified isolates that were virulent on at least one of the following defined resistance gene hosts: h(1), h(2), h(3), h(4), h(5), h(6), h(7), h(8), h(9), h(10), and h(13). Sixteen different virulence patterns were observed. In general, the isolates carried one to three virulences, but some of them were more complex, with up to six virulences. This set of well-characterized isolates will be helpful for the identification of additional apple scab resistance genes in apple germplasm and the characterization of new GfG relationships to help improve our understanding of the host-pathogen interactions in the V. inaequalis-Malus pathosystem.
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Affiliation(s)
- Valérie Caffier
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, 49071 Beaucouzé, France; AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, 49045 Angers, France; Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR 4207 QUASAV, 49045 Angers, France
| | - Andrea Patocchi
- Agroscope Research Station, Phytopathology, P.B., 8820 Wädenswil, Switzerland
| | - Pascale Expert
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, 49071 Beaucouzé, France; AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, 49045 Angers, France; Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR 4207 QUASAV, 49045 Angers, France
| | - Marie-Noëlle Bellanger
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, 49071 Beaucouzé, France; AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, 49045 Angers, France; Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR 4207 QUASAV, 49045 Angers, France
| | - Charles-Eric Durel
- INRA, UMR1345 Institut de Recherche en Horticulture et Semences, 49071 Beaucouzé, France; AgroCampus-Ouest, UMR1345 Institut de Recherche en Horticulture et Semences, 49045 Angers, France; Université d'Angers, UMR1345 Institut de Recherche en Horticulture et Semences, SFR 4207 QUASAV, 49045 Angers, France
| | - Maja Hilber-Bodmer
- Agroscope Research Station, Phytopathology, P.B., 8820 Wädenswil, Switzerland
| | - Giovanni A L Broggini
- Agroscope Research Station, Phytopathology, P.B., 8820 Wädenswil, Switzerland; Swiss Federal Institute of Technology Zürich ETHZ, Phytopathology Group, Universitätstrasse 2, Zürich, Switzerland
| | - Remmelt Groenwold
- Wageningen University and Research, Plant Breeding, P.O. Box 16, 6700AA Wageningen, The Netherlands
| | - Vincent G M Bus
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 1401, Havelock North 4157, New Zealand
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32
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Beckerman JL, Sundin GW, Rosenberger DA. Do some IPM concepts contribute to the development of fungicide resistance? Lessons learned from the apple scab pathosystem in the United States. PEST MANAGEMENT SCIENCE 2015; 71:331-342. [PMID: 24375947 DOI: 10.1002/ps.3715] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/19/2013] [Accepted: 12/11/2013] [Indexed: 06/03/2023]
Abstract
One goal of integrated pest management (IPM) as it is currently practiced is an overall reduction in fungicide use in the management of plant disease. Repeated and long-term success of the early broad-spectrum fungicides led to optimism about the capabilities of fungicides, but to an underestimation of the risk of fungicide resistance within agriculture. In 1913, Paul Ehrlich recognized that it was best to 'hit hard and hit early' to prevent microbes from evolving resistance to treatment. This tenet conflicts with the fungicide reduction strategies that have been widely promoted over the past 40 years as integral to IPM. The authors hypothesize that the approaches used to implement IPM have contributed to fungicide resistance problems and may still be driving that process in apple scab management and in IPM requests for proposals. This paper also proposes that IPM as it is currently practiced for plant diseases of perennial systems has been based on the wrong model, and that conceptual shifts in thinking are needed to address the problem of fungicide resistance.
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Affiliation(s)
- Janna L Beckerman
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, USA
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33
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Villani SM, Cox KD. Heteroplasmy of the cytochrome b gene in Venturia inaequalis and its involvement in quantitative and practical resistance to trifloxystrobin. PHYTOPATHOLOGY 2014; 104:945-953. [PMID: 24624954 DOI: 10.1094/phyto-06-13-0158-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Quantitative (partial) and qualitative (complete) resistance responses to quinone outside inhibitor (QoI) fungicides have been documented for the apple scab pathogen Venturia inaequalis. Resistance monitoring efforts have traditionally focused on the detection of qualitative resistance based on a single point mutation, G143A, within the cytochrome b (cyt b) gene. In order to better understand the role of heteroplasmy of the cyt b gene in the QoI resistance response for isolates and populations of V. inaequalis, an allele-specific quantitative polymerase chain reaction was developed to quantify the relative abundance of the A143 (resistant) allele in 45 isolates of V. inaequalis with differing in vitro resistance responses to the QoI fungicide trifloxystrobin. Although a high relative abundance of the A143 allele (>62%) was associated with isolates with high resistance responses (50 to 100% relative growth on trifloxystrobin-amended medium), heteroplasmy of the cyt b gene was not the primary factor involved in isolates with moderate resistance responses (29 to 49% relative growth). The relative abundance of the A143 allele in isolates with moderate resistance to trifloxystrobin rarely exceeded 8%, suggesting that other resistance mechanisms are involved in moderate resistance and, therefore, that the Qol resistance response is polygenic. In research orchards where QoI fungicides failed to control apple scab (practical resistance), field trials were conducted to demonstrate the link between practical resistance and the abundance of the A143 allele. Relative abundance of the A143 allele in these orchard populations exceeded 20% in 2011 and 2012. Similarly, of the eight additional commercial orchards screened in 2011, the relative abundance of the A143 allele always exceeded 20% in those with QoI practical resistance. Although heteroplasmy of the cyt b gene did not entirely explain the response of isolates with moderate resistance to QoIs, the relative abundance of A143 in orchard populations of V. inaequalis helps to explain the point of emergence for practical resistance to trifloxystrobin across several orchard populations with differing production histories.
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Frederick ZA, Villani SM, Cooley DR, Biggs AR, Raes JJ, Cox KD. Prevalence and Stability of Qualitative QoI Resistance in Populations of Venturia inaequalis in the Northeastern United States. PLANT DISEASE 2014; 98:1122-1130. [PMID: 30708794 DOI: 10.1094/pdis-10-13-1042-re] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Quinone-outside-inhibitor (QoI) fungicides are a safe and effective means of managing apple scab caused by Venturia inaequalis. To determine the prevalence of both quantitative (partial) and qualitative (complete) QoI resistance in V. inaequalis in the northeastern United States, we sampled single-lesion conidial isolates (n = 4,481) from 120 commercial and research orchards from 2004 to 2011 with a range of exposure to QoI fungicides from none to several applications a year. In all, 67% of these orchard populations of V. inaequalis were sensitive to QoI fungicides, 28% exhibited QoI practical resistance, and 5% were not sensitive QoI fungicides but had not become practically resistant. Isolates with qualitative QoI resistance, conferred by the G143A cytochrome b gene mutation, were found in 13 of the 34 QoI-resistant orchard populations. To evaluate the stability of the G143A mutation, 27 isolates were selected from different orchard populations to represent the scope of regional populations. These isolates were subcultured continuously in the presence or absence of the QoI fungicide trifloxystrobin. All isolates that initially possessed qualitative resistance maintained the resistant genotype (G143A) for six transfers over 6 months in both the absence and presence of trifloxystrobin. Given the observed QoI resistance in orchard populations of V. inaequalis and the stability of the G143A mutation in individual isolates, apple scab management paradigms must encompass strategies to limit selection of QoI resistance in the sensitive orchard populations remaining in the region.
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Affiliation(s)
- Zachary A Frederick
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456
| | - Sara M Villani
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456
| | - Daniel R Cooley
- Department Plant, Soil, and Insect Science, University of Massachusetts, Amherst 01003
| | - Alan R Biggs
- Kearneysville Tree Fruit Research and Education Center, West Virginia University, Kearneysville 25443
| | - Jessica J Raes
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University
| | - Kerik D Cox
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University
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Lesniak KE, Proffer TJ, Beckerman JL, Sundin GW. Occurrence of QoI Resistance and Detection of the G143A Mutation in Michigan Populations of Venturia inaequalis. PLANT DISEASE 2011; 95:927-934. [PMID: 30732103 DOI: 10.1094/pdis-12-10-0898] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Control strategies for Venturia inaequalis rely heavily on chemical fungicides. Single-site fungicides such as the quinone-outside inhibitors (QoI) have been used in Michigan apple orchards for more than 11 years. In 2008, we sampled eight commercial orchards in the Fruit Ridge growing region of Michigan in which apple scab control failures were observed on 'McIntosh' apple following applications of kresoxim-methyl or trifloxystrobin. QoI resistance was assessed in 210 total isolates (a total of 17 orchards) using a spore germination assay and in 319 isolates using a polymerase chain reaction (PCR) assay to detect the G143A mutation located within the V. inaequalis cytochrome b gene (CYTB). The G143A mutation is known to confer high-level QoI resistance in plant-pathogenic fungi. QoI resistance was confirmed in 50 and 64% of the isolates tested with the spore germination and PCR assays, respectively, and there was a 97% concordance observed between the assays. In 2009, we sampled and examined an additional 1,201 V. inaequalis isolates from 64 orchards in Michigan and 86 isolates from four baseline sites in Ohio. All of these isolates were assayed for the G143A mutation and it was detected within 67 and 0% of the Michigan and Ohio isolates, respectively. Our results indicate the widespread occurrence of QoI resistance in Michigan commercial orchard populations of V. inaequalis. Loss of QoI fungicides further limits the arsenal of fungicides available to commercial apple growers for successful scab management.
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Affiliation(s)
- Kimberley E Lesniak
- Department of Plant Pathology, Michigan State University, East Lansing 48824
| | - Tyre J Proffer
- Department of Plant Pathology, Michigan State University, East Lansing and Department of Biological Sciences, Kent State University, Salem, OH 44460
| | - Janna L Beckerman
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907
| | - George W Sundin
- Department of Plant Pathology, Michigan State University, East Lansing
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