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Seress D, Molnár O, Matolcsi F, Pintye A, Kovács GM, Németh MZ. Development and Implementation of a Novel CAPS Assay Reveals High Prevalence of a Boscalid Resistance Marker and Its Co-Occurrence with an Azole Resistance Marker in Erysiphe necator. PLANT DISEASE 2024; 108:2607-2614. [PMID: 38616393 DOI: 10.1094/pdis-06-23-1114-sr] [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: 04/16/2024]
Abstract
Succinate dehydrogenase inhibitors (SDHIs) are frequently used against powdery mildew (PM) fungi, such as Erysiphe necator, the causal agent of grapevine PM. Fungicide resistance, however, hinders effective control. DNA-based monitoring facilitates the recognition of resistance. We aimed (i) to adapt an effective method to detect a widespread genetic marker of resistance to boscalid, a commonly used SDHI, and (ii) to study the co-occurrence of the marker with a marker of resistance to demethylase inhibitor (DMI) fungicides. Sequencing of the sdhB gene identified a nonsynonymous substitution, denoted as sdhB-A794G, leading to an amino acid change (H242R) in the sdhB protein. In vitro fungicide resistance tests showed that E. necator isolates carrying sdhB-A794G were resistant to boscalid. We adopted a cleaved amplified polymorphic sequence-based method and screened more than 500 field samples collected from five Hungarian wine regions in two consecutive years. The sdhB-A794G marker was detected in all wine regions and in both years, altogether in 61.7% of samples, including 20.5% in which both sdhB-A794G and the wild-type were present. The frequency of sdhB-A794G was higher in SDHI-treated vineyards than in vineyards without any SDHI application. A significant difference in the presence of the marker was detected among wine regions; its prevalence ranged from none to 100%. We identified significant co-occurrence of sdhB-A794G with the CYP51-A495T (Y136F) mutation of the CYP51 gene, a known marker of resistance to DMIs. The monitoring of fungicide resistance is fundamental for the successful control of E. necator. Our rapid, cost-effective diagnostic method will support decision-making and fungicide resistance monitoring and management.
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Affiliation(s)
- Diána Seress
- Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest 1022, Hungary
| | - Orsolya Molnár
- Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest 1022, Hungary
| | - Fruzsina Matolcsi
- Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest 1022, Hungary
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest 1117, Hungary
| | - Alexandra Pintye
- Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest 1022, Hungary
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest 1117, Hungary
| | - Gábor M Kovács
- Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest 1022, Hungary
- Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Budapest 1117, Hungary
| | - Márk Z Németh
- Plant Protection Institute, HUN-REN Centre for Agricultural Research, Budapest 1022, Hungary
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2
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Wong AT, Gadoury DM, Mahaffee WF. Evaluation of Germicidal UV-C Light for Suppression of Grape Powdery Mildew and Botrytis Bunch Rot in Western Oregon. PLANT DISEASE 2024; 108:2894-2905. [PMID: 38831592 DOI: 10.1094/pdis-02-24-0279-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: 06/05/2024]
Abstract
Germicidal UV light (UV-C) has been shown to effectively suppress several plant pathogens as well as some arthropod pests. Recent reports describe the efficacy of nighttime applications of UV-C at doses from 100 to 200 J/m2 in vineyards to reduce grape powdery mildew (Erysiphe necator). Our in vitro studies confirmed the efficacy of UV-C to inhibit germination of E. necator and Botrytis cinerea conidia, demonstrated a range of tolerances to UV-C within a collection of E. necator isolates, and showed growth stage-specific effects of UV-C on B. cinerea. Nighttime use of UV-C was evaluated at 48 to 96 J/m2 in small plot trials (<1,000 vines) from 2020 to 2023. Once- or twice-weekly UV-C applications significantly reduced the incidence of foliar powdery mildew compared with non-UV-C-treated controls (P < 0.02). Suppression of powdery mildew on fruit was less consistent, where once or twice weekly UV-C exposure reduced powdery mildew disease severity in 2020 (P = 0.04), 2021 (P = 0.02), and 2023 (P = 0.003) but less so in 2022 (P = 0.07). Bunch rot severity was not significantly reduced with UV-C treatment in any year of the study. Application of UV-C until the onset of fruit color change (veraison) also had a minimal effect on the fruit-soluble solids, pH, anthocyanins, or phenolics in harvested fruit at any UV-C dose or frequency (P > 0.10). Suppression of powdery mildew by nighttime application of UV-C at lower doses in small plots suggests that such treatments merit further evaluation in larger-scale studies in Western Oregon.
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Affiliation(s)
- Alexander Thomas Wong
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97330
| | - David M Gadoury
- Plant Pathology and Plant-Microbe Biology Section, Cornell AgriTech, Geneva, NY 14456
| | - Walter F Mahaffee
- United States Department of Agriculture, Agricultural Research Service (USDA ARS), Horticultural Crops Research Unit, Corvallis, OR 97330
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3
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Check JC, Harkness RJ, Heger L, Sakalidis ML, Chilvers MI, Mahaffee WF, Miles TD. It's a Trap! Part I: Exploring the Applications of Rotating-Arm Impaction Samplers in Plant Pathology. PLANT DISEASE 2024; 108:1910-1922. [PMID: 38411610 DOI: 10.1094/pdis-10-23-2096-fe] [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: 02/28/2024]
Abstract
Although improved knowledge on the movement of airborne plant pathogens is likely to benefit plant health management, generating this knowledge is often far more complicated than anticipated. This complexity is driven by the dynamic nature of environmental variables, diversity among pathosystems that are targeted, and the unique needs of each research group. When using a rotating-arm impaction sampler, particle collection is dependent on the pathogen, environment, research objectives, and limitations (monetary, environmental, or labor). Consequently, no design will result in 100% collection efficiency. Fortunately, it is likely that multiple approaches can succeed despite these constraints. Choices made during design and implementation of samplers can influence the results, and recognizing this influence is crucial for researchers. This article is for beginners in the art and science of using rotating-arm impaction samplers; it provides a foundation for designing a project, from planning the experiment to processing samples. We present a relatively nontechnical discussion of the factors influencing pathogen dispersal and how placement of the rotating-arm air samplers alters propagule capture. We include a discussion of applications of rotating-arm air samplers to demonstrate their versatility and potential in plant pathology research as well as their limitations.
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Affiliation(s)
- Jill C Check
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Rebecca J Harkness
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Lexi Heger
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Monique L Sakalidis
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
- Department of Forestry, Michigan State University, East Lansing, MI 48824, U.S.A
- Department of Industries and Regional Development, South Perth, WA 6151, Australia
| | - Martin I Chilvers
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Walter F Mahaffee
- USDA Agricultural Research Service, Horticulture Crops Disease and Pest Management Research Unit, Corvallis, OR 97330, U.S.A
| | - Timothy D Miles
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
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4
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Oliver C, Cooper M, Ivey ML, Brannen P, Miles T, Lowder S, Mahaffee W, Moyer MM. Fungicide Use Patterns in Select United States Wine Grape Production Regions. PLANT DISEASE 2024; 108:104-112. [PMID: 37486275 DOI: 10.1094/pdis-04-23-0798-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: 07/25/2023]
Abstract
Wine grape production (Vitis sp.) in the United States requires fungicide inputs for disease control. Currently, there is limited data available on vineyard fungicide use patterns. This information is important in developing tailored recommendations for disease management and fungicide stewardship. In this paper, we summarize the wine grape vineyard fungicide use patterns from four major regions: Napa and Sonoma valleys (California), Willamette Valley (Oregon), Columbia Valley (Washington), and several smaller regions east of the Mississippi River in years 2009 to 2020. We learned that the average in-season total fungicide applications ranged regionally from 5.6 to 8. The most commonly applied Fungicide Resistance Action Committee (FRAC) codes in spray programs were FRAC 3, 13, and M02 across all regions, with some variation to the top four groups in each region. Most applications were made on 14-day intervals; however, shorter intervals (7-day) were favored early season, and longer intervals (21-day) were favored late season. Tank-mixing multiple active ingredients was common east of the Mississippi River during all stages of grape development; this action was typically favored during the bloom period in other regions. In a subset of records that participated in FRAC 11 fungicide resistance testing, the average number of FRAC 11 applications after testing was reduced to either no applications or one application in Napa and Sonoma valleys. This survey provides regionally specific data related to fungicide stewardship practices that could be a focus for future stewardship messaging and fungicide resistance selection training, including total product use (selection events), spray intervals (selection pressure), and tank mixing (selection management).[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Charlotte Oliver
- Washington State University Irrigated Agriculture Research and Extension Center, Prosser, WA 99350
| | - Monica Cooper
- Cooperative Extension, University of California, Napa, CA 94559
| | | | - Phillip Brannen
- Plant Pathology Department, University of Georgia, Athens, GA 30602
| | - Timothy Miles
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI 48824
| | - Sarah Lowder
- Agriculture Research Service Horticulture Crops Research Unit, United States Department of Agriculture, Corvallis, OR 97331
| | - Walter Mahaffee
- Agriculture Research Service Horticulture Crops Research Unit, United States Department of Agriculture, Corvallis, OR 97331
| | - Michelle M Moyer
- Washington State University Irrigated Agriculture Research and Extension Center, Prosser, WA 99350
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Sharma N, Neill T, Yang HC, Oliver CL, Mahaffee WF, Naegele R, Moyer MM, Miles TD. Development of a PNA-LNA-LAMP Assay to Detect an SNP Associated with QoI Resistance in Erysiphe necator. PLANT DISEASE 2023; 107:3238-3247. [PMID: 37005502 DOI: 10.1094/pdis-09-22-2027-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: 06/19/2023]
Abstract
The repetitive use of quinone outside inhibitor fungicides (QoIs, strobilurins; Fungicide Resistance Action Committee [FRAC] 11) to manage grape powdery mildew has led to development of resistance in Erysiphe necator. While several point mutations in the mitochondrial cytochrome b gene are associated with resistance to QoI fungicides, the substitution of glycine to alanine at codon 143 (G143A) has been the only mutation observed in QoI-resistant field populations. Allele-specific detection methods such as digital droplet PCR and TaqMan probe-based assays can be used to detect the G143A mutation. In this study, a peptide nucleic acid-locked nucleic acid mediated loop-mediated isothermal amplification (PNA-LNA-LAMP) assay consisting of an A-143 reaction and a G-143 reaction, was designed for rapidly detecting QoI resistance in E. necator. The A-143 reaction amplifies the mutant A-143 allele faster than the wild-type G-143 allele, while the G-143 reaction amplifies the G-143 allele faster than the A-143 allele. Identification of resistant or sensitive E. necator samples was determined by which reaction had the shorter time to amplification. Sixteen single-spore QoI-resistant and -sensitive E. necator isolates were tested using both assays. Assay specificity in distinguishing the single nucleotide polymorphism (SNP) approached 100% when tested using purified DNA of QoI-sensitive and -resistant E. necator isolates. This diagnostic tool was sensitive to one-conidium equivalent of extracted DNA with an R2 value of 0.82 and 0.87 for the G-143 and A-143 reactions, respectively. This diagnostic approach was also evaluated against a TaqMan probe-based assay using 92 E. necator samples collected from vineyards. The PNA-LNA-LAMP assay detected QoI resistance in ≤30 min and showed 100% agreement with the TaqMan probe-based assay (≤1.5 h) for the QoI-sensitive and -resistant isolates. There was 73.3% agreement with the TaqMan probe-based assay when samples had mixed populations with both G-143 and A-143 alleles present. Validation of the PNA-LNA-LAMP assay was conducted in three different laboratories with different equipment. The results showed 94.4% accuracy in one laboratory and 100% accuracy in two other laboratories. The PNA-LNA-LAMP diagnostic tool was faster and required less expensive equipment relative to the previously developed TaqMan probe-based assay, making it accessible to a broader range of diagnostic laboratories for detection of QoI resistance in E. necator. This research demonstrates the utility of the PNA-LANA-LAMP for discriminating SNPs from field samples and its utility for point-of-care monitoring of plant pathogen genotypes.
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Affiliation(s)
- Nancy Sharma
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI
| | - Tara Neill
- USDA-ARS Horticultural Crops Disease and Pest Management Research Unit, Corvallis, OR
| | - Hui-Ching Yang
- USDA-ARS Crop Diseases, Pests and Genetics Unit, San Joaquin Valley Agricultural Sciences Center, Parlier, CA
| | - Charlotte L Oliver
- Department of Horticulture, Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA
| | - Walter F Mahaffee
- USDA-ARS Horticultural Crops Disease and Pest Management Research Unit, Corvallis, OR
| | - Rachel Naegele
- USDA-ARS Crop Diseases, Pests and Genetics Unit, San Joaquin Valley Agricultural Sciences Center, Parlier, CA
| | - Michelle M Moyer
- Department of Horticulture, Irrigated Agriculture Research and Extension Center, Washington State University, Prosser, WA
| | - Timothy D Miles
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI
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6
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Lowder SR, Neill TM, Peetz AB, Miles TD, Moyer MM, Oliver C, Stergiopoulos I, Ding S, Mahaffee WF. A Rapid Glove-Based Inoculum Sampling Technique to Monitor Erysiphe necator in Commercial Vineyards. PLANT DISEASE 2023; 107:3096-3105. [PMID: 37079020 DOI: 10.1094/pdis-02-23-0216-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Information on the presence and severity of grape powdery mildew (GPM), caused by Erysiphe necator, has long been used to guide management decisions. While recent advances in the available molecular diagnostic assays and particle samplers have made monitoring easier, there is still a need for more efficient field collection of E. necator. The use of vineyard worker gloves worn during canopy manipulation as a sampler (glove swab) of E. necator was compared with samples identified by visual assessment with subsequent molecular confirmation (leaf swabs) and airborne spore samples collected by rotating-arm impaction traps (impaction traps). Samples from United States commercial vineyards in Oregon, Washington, and California were analyzed using two TaqMan qPCR assays targeting the internal transcribed spacer regions or cytochrome b gene of E. necator. Based on qPCR assays, visual disease assessments misidentified GPM up to 59% of the time with a higher frequency of misidentification occurring earlier in the growing season. Comparison of the aggregated leaf swab results for a row (n = 915) to the row's corresponding glove swab had 60% agreement. The latent class analysis (LCA) indicated that glove swabs were more sensitive than leaf swabs in detecting E. necator presence. The impaction trap results had 77% agreement to glove swabs (n = 206) taken from the same blocks. The LCAs estimated that the glove swabs and impaction trap samplers varied each year in which was more sensitive for detection. This likely indicates that these methods have similar levels of uncertainty and provide equivalent information. Additionally, all samplers, once E. necator was detected, were similarly sensitive and specific for detection of the A-143 resistance allele. Together, these results suggest that glove swabs are an effective sampling method for monitoring the presence of E. necator and, subsequently, the G143A amino acid substitution associated with resistance to quinone outside inhibitor fungicides in vineyards. Glove swabs could reduce sampling costs due to the lack of need for specialized equipment and time required for swab collection and processing.
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Affiliation(s)
- Sarah R Lowder
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | - Tara M Neill
- USDA-ARS Horticultural Crops Disease and Pest Management Research Unit, Corvallis, OR 97330
| | - Amy B Peetz
- Revolution Crop Consultants, LLC, Albany, OR 97321
| | - Timothy D Miles
- Department of Plant, Soil, and Microbial Science, Michigan State University, East Lansing, MI 48824
| | - Michelle M Moyer
- Department of Viticulture and Enology, Washington State University, Prosser, WA 99350
| | | | | | - Shunping Ding
- Department of Wine and Viticulture, California Polytechnic State University, San Luis Obispo, CA 93407
| | - Walter F Mahaffee
- USDA-ARS Horticultural Crops Disease and Pest Management Research Unit, Corvallis, OR 97330
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7
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McRae AG, Taneja J, Yee K, Shi X, Haridas S, LaButti K, Singan V, Grigoriev IV, Wildermuth MC. Spray-induced gene silencing to identify powdery mildew gene targets and processes for powdery mildew control. MOLECULAR PLANT PATHOLOGY 2023; 24:1168-1183. [PMID: 37340595 PMCID: PMC10423327 DOI: 10.1111/mpp.13361] [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: 09/13/2022] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 06/22/2023]
Abstract
Spray-induced gene silencing (SIGS) is an emerging tool for crop pest protection. It utilizes exogenously applied double-stranded RNA to specifically reduce pest target gene expression using endogenous RNA interference machinery. In this study, SIGS methods were developed and optimized for powdery mildew fungi, which are widespread obligate biotrophic fungi that infect agricultural crops, using the known azole-fungicide target cytochrome P450 51 (CYP51) in the Golovinomyces orontii-Arabidopsis thaliana pathosystem. Additional screening resulted in the identification of conserved gene targets and processes important to powdery mildew proliferation: apoptosis-antagonizing transcription factor in essential cellular metabolism and stress response; lipid catabolism genes lipase a, lipase 1, and acetyl-CoA oxidase in energy production; and genes involved in manipulation of the plant host via abscisic acid metabolism (9-cis-epoxycarotenoid dioxygenase, xanthoxin dehydrogenase, and a putative abscisic acid G-protein coupled receptor) and secretion of the effector protein, effector candidate 2. Powdery mildew is the dominant disease impacting grapes and extensive powdery mildew resistance to applied fungicides has been reported. We therefore developed SIGS for the Erysiphe necator-Vitis vinifera system and tested six successful targets identified using the G. orontii-A. thaliana system. For all targets tested, a similar reduction in powdery mildew disease was observed between systems. This indicates screening of broadly conserved targets in the G. orontii-A. thaliana pathosystem identifies targets and processes for the successful control of other powdery mildew fungi. The efficacy of SIGS on powdery mildew fungi makes SIGS an exciting prospect for commercial powdery mildew control.
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Affiliation(s)
- Amanda G. McRae
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Jyoti Taneja
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Kathleen Yee
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Xinyi Shi
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Sajeet Haridas
- US Department of Energy Joint Genome InstituteLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - Kurt LaButti
- US Department of Energy Joint Genome InstituteLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - Vasanth Singan
- US Department of Energy Joint Genome InstituteLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - Igor V. Grigoriev
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
- US Department of Energy Joint Genome InstituteLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - Mary C. Wildermuth
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
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8
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Zaccaron AZ, Neill T, Corcoran J, Mahaffee WF, Stergiopoulos I. A chromosome-scale genome assembly of the grape powdery mildew pathogen Erysiphe necator reveals its genomic architecture and previously unknown features of its biology. mBio 2023; 14:e0064523. [PMID: 37341476 PMCID: PMC10470754 DOI: 10.1128/mbio.00645-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/13/2023] [Indexed: 06/22/2023] Open
Abstract
Erysiphe necator is an obligate fungal pathogen that causes grape powdery mildew, globally the most important disease on grapevines. Previous attempts to obtain a quality genome assembly for this pathogen were hindered by its high repetitive DNA content. Here, chromatin conformation capture (Hi-C) with long-read PacBio sequencing was combined to obtain a chromosome-scale assembly and a high-quality annotation for E. necator isolate EnFRAME01. The resulting 81.1 Mb genome assembly is 98% complete and consists of 34 scaffolds, 11 of which represent complete chromosomes. All chromosomes contain large centromeric-like regions and lack synteny to the 11 chromosomes of the cereal PM pathogen Blumeria graminis. Further analysis of their composition showed that repeats and transposable elements (TEs) occupy 62.7% of their content. TEs were almost evenly interspersed outside centromeric and telomeric regions and massively overlapped with regions of annotated genes, suggesting that they could have a significant functional impact. Abundant gene duplicates were observed as well, particularly in genes encoding candidate secreted effector proteins. Moreover, younger in age gene duplicates exhibited more relaxed selection pressure and were more likely to be located physically close in the genome than older duplicates. A total of 122 genes with copy number variations among six isolates of E. necator were also identified and were enriched in genes that were duplicated in EnFRAME01, indicating they may reflect an adaptive variation. Taken together, our study illuminates higher-order genomic architectural features of E. necator and provides a valuable resource for studying genomic structural variations in this pathogen. IMPORTANCE Grape powdery mildew caused by the ascomycete fungus Erysiphe necator is economically the most important and recurrent disease in vineyards across the world. The obligate biotrophic nature of E. necator hinders the use of typical genetic methods to elucidate its pathogenicity and adaptation to adverse conditions, and thus comparative genomics has been a major method to study its genome biology. However, the current reference genome of E. necator isolate C-strain is highly fragmented with many non-coding regions left unassembled. This incompleteness prohibits in-depth comparative genomic analyses and the study of genomic structural variations (SVs) that are known to affect several aspects of microbial life, including fitness, virulence, and host adaptation. By obtaining a chromosome-scale genome assembly and a high-quality gene annotation for E. necator, we reveal the organization of its chromosomal content, unearth previously unknown features of its biology, and provide a reference for studying genomic SVs in this pathogen.
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Affiliation(s)
- Alex Z. Zaccaron
- Department of Plant Pathology, University of California Davis, Davis, California, USA
| | - Tara Neill
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Jacob Corcoran
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Walter F. Mahaffee
- USDA-ARS, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, Oregon, USA
| | - Ioannis Stergiopoulos
- Department of Plant Pathology, University of California Davis, Davis, California, USA
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9
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Stergiopoulos I, Aoun N, van Huynh Q, Neill T, Lowder SR, Newbold C, Cooper ML, Ding S, Moyer MM, Miles TD, Oliver CL, Úrbez-Torres JR, Mahaffee WF. Identification of Putative SDHI Target Site Mutations in the SDHB, SDHC, and SDHD Subunits of the Grape Powdery Mildew Pathogen Erysiphe necator. PLANT DISEASE 2022; 106:2310-2320. [PMID: 35100029 DOI: 10.1094/pdis-09-21-1993-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Succinate dehydrogenase inhibitors (SDHIs) are fungicides used in control of numerous fungal plant pathogens, including Erysiphe necator, the causal agent of grapevine powdery mildew (GPM). Here, the sdhb, sdhc, and sdhd genes of E. necator were screened for mutations that may be associated with SDHI resistance. GPM samples were collected from 2017 to 2020 from the U.S. states of California, Oregon, Washington, and Michigan, and the Canadian province of British Columbia. Forty-five polymorphisms were identified in the three sdh genes, 17 of which caused missense mutations. Of these, the SDHC-p.I244V substitution was shown in this study to reduce sensitivity of E. necator to boscalid and fluopyram, whereas the SDHC-p.G25R substitution did not affect SDHI sensitivity. Of the other 15 missense mutations, the SDHC-p.H242R substitution was shown in previous studies to reduce sensitivity of E. necator toward boscalid, whereas the equivalents of the SDHB-p.H242L, SDHC-p.A83V, and SDHD-p.I71F substitutions were shown to reduce sensitivity to SDHIs in other fungi. Generally, only a single amino acid substitution was present in the SDHB, SDHC, or SDHD subunit of E. necator isolates, but missense mutations putatively associated with SDHI resistance were widely distributed in the sampled areas and increased in frequency over time. Finally, isolates that had decreased sensitivity to boscalid or fluopyram were identified but with no or only the SDHC-p.G25R amino acid substitution present in SDHB, SDHC, and SDHD subunits. This suggests that target site mutations probably are not the only mechanism conferring resistance to SDHIs in E. necator.
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Affiliation(s)
- Ioannis Stergiopoulos
- Department of Plant Pathology, University of California Davis, Davis, CA 95616-851, U.S.A
| | - Nathalie Aoun
- Department of Plant Pathology, University of California Davis, Davis, CA 95616-851, U.S.A
| | - Que van Huynh
- Department of Plant Pathology, University of California Davis, Davis, CA 95616-851, U.S.A
| | - Tara Neill
- USDA-ARS Horticulture Crops Disease and Pest Management Research Unit (HCDPMRU), Corvallis, OR 97330, U.S.A
| | - Sarah R Lowder
- Department of Botany and Plant Pathology, Oregon State University, Cordley Hall, OR 97331, U.S.A
| | - Chelsea Newbold
- Department of Botany and Plant Pathology, Oregon State University, Cordley Hall, OR 97331, U.S.A
| | - Monica L Cooper
- University of California Cooperative Extension, Napa, CA 94559, U.S.A
| | - Shunping Ding
- Wine and Viticulture Department, California Polytechnical State University, San Luis Obispo, CA 93407, U.S.A
| | - Michelle M Moyer
- Department of Horticulture, Washington State University Irrigated Agriculture Research and Extension Center, Prosser, WA 99350, U.S.A
| | - Timothy D Miles
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, U.S.A
| | - Charlotte L Oliver
- Department of Horticulture, Washington State University Irrigated Agriculture Research and Extension Center, Prosser, WA 99350, U.S.A
| | - José Ramón Úrbez-Torres
- Agriculture and Agri-Food Canada, Summerland Research and Development Centre, Summerland, British Columbia V0H 1Z0, Canada
| | - Walter F Mahaffee
- USDA-ARS Horticulture Crops Disease and Pest Management Research Unit (HCDPMRU), Corvallis, OR 97330, U.S.A
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Crandall SG, Spychalla J, Crouch UT, Acevedo FE, Naegele RP, Miles TD. Rotting Grapes Don't Improve with Age: Cluster Rot Disease Complexes, Management, and Future Prospects. PLANT DISEASE 2022; 106:2013-2025. [PMID: 35108071 DOI: 10.1094/pdis-04-21-0695-fe] [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: 06/14/2023]
Abstract
Cluster rots can be devastating to grape production around the world. There are several late-season rots that can affect grape berries, including Botrytis bunch rot, sour rot, black rot, Phomopsis fruit rot, bitter rot, and ripe rot. Tight-clustered varieties such as 'Pinot gris', 'Pinot noir', and 'Vignoles' are particularly susceptible to cluster rots. Symptoms or signs for these rots range from discolored berries or gray-brown sporulation in Botrytis bunch rot to sour rot, which smells distinctly of vinegar due to the presence of acetic acid bacteria. This review discusses the common symptoms and disease cycles of these different cluster rots. It also includes useful updates on disease diagnostics and management practices, including cultural practices in commercial vineyards and future prospects for disease management. By understanding what drives the development of different cluster rots, researchers will be able to identify new avenues for research to control these critical pathogens.
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Affiliation(s)
- Sharifa G Crandall
- Pennsylvania State University, Department of Plant Pathology & Environmental Microbiology, University Park, PA 16802
| | - Jamie Spychalla
- Pennsylvania State University, Department of Plant Pathology & Environmental Microbiology, University Park, PA 16802
| | - Uma T Crouch
- Pennsylvania State University, Department of Plant Pathology & Environmental Microbiology, University Park, PA 16802
| | - Flor E Acevedo
- Pennsylvania State University, Department of Entomology, University Park, PA 16802
| | - Rachel P Naegele
- United States Department of Agriculture-Agricultural Research Station, Parlier, CA 93648
| | - Timothy D Miles
- Michigan State University, Department of Plant, Soil and Microbial Sciences, East Lansing, MI 48824
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11
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A New Approach: Determining cyt b G143A Allele Frequency in Zymoseptoria tritici by Digital Droplet PCR. BIOLOGY 2022; 11:biology11020240. [PMID: 35205106 PMCID: PMC8869461 DOI: 10.3390/biology11020240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/31/2022] [Accepted: 02/01/2022] [Indexed: 11/17/2022]
Abstract
Z. tritici first appeared in Italy later than in northern-central European countries. QoIs fungicides currently play a role in STB control, used in combination with Demethylation Inhibitors (DMIs) or Succinate dehydrogenase Inhibitors (SDHIs). In this study, we set up a fast, sensitive, and accurate ddPCR protocol in order to investigate the presence and frequency of G143A substitution, causing a reduction in strobilurins’ efficacy in Z. tritici. The best PCR conditions for the clear separation of positive and negative droplets were identified. The lowest wild-type and resistant alleles frequencies were accurately determined on samples consisting of mixed DNAs from monoconidial cultures of Z. tritici and were expressed as fractional abundance. The protocol was tested by determining the copy number and frequency of alleles on gDNA purified in three Italian Z. tritici field populations representative of different fungicide management strategies. For the first time, the determination of allele concentration and the frequency of a mutation involved in Z. tritici fungicide resistance was carried out by employing digital PCR. This new approach provides a diagnostic tool that is rapid and able to detect very low G143A substitution percentages, which is very useful for fungicide resistance detection at early stages, thus, informing field management strategies for contrasting STB disease.
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12
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Lowder SR, Neill TM, Miles TM, Moyer MM, Oliver C, Ding S, Mahaffee WF. Rapid sampling technique to monitor Erysiphe necator more effective than visual scouting. BIO WEB OF CONFERENCES 2022. [DOI: 10.1051/bioconf/20225003014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Hoheisel GA, Moyer M. The role of sprayer design and education in controlling Erysiphe necator. BIO WEB OF CONFERENCES 2022. [DOI: 10.1051/bioconf/20225001004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Santos RF, Amorim L, Wood AKM, Bibiano LBJ, Fraaije BA. Lack of an Intron in Cytochrome b and Overexpression of Sterol 14α-Demethylase Indicate a Potential Risk for QoI and DMI Resistance Development in Neophysopella spp. on Grapes. PHYTOPATHOLOGY 2021; 111:1726-1734. [PMID: 33703921 DOI: 10.1094/phyto-11-20-0514-r] [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: 06/12/2023]
Abstract
Asian grapevine leaf rust, caused by Neophysopella meliosmae-myrianthae and N. tropicalis, is often controlled by quinone outside inhibitor (QoI) and demethylation inhibitor (DMI) fungicides in Brazil. Here, we evaluated the sensitivity of 55 Neophysopella spp. isolates to pyraclostrobin (QoI) and tebuconazole (DMI). To elucidate the resistance mechanisms, we analyzed the sequences of the cytochrome b (CYTB) and cytochrome P450 sterol 14α-demethylase (CYP51) target proteins of QoI and DMI fungicides, respectively. The CYP51 expression levels were also determined in a selection of isolates. In leaf disc assays, the mean 50% effective concentration (EC50) value for pyraclostrobin was about 0.040 µg/ml for both species. CYTB sequences were identical among all 55 isolates, which did not contain an intron immediately after codon 143. No amino acid substitution was identified at codons 129, 137, and 143. The mean EC50 value for tebuconazole was 0.62 µg/ml for N. tropicalis and 0.46 µg/ml for N. meliosmae-myrianthae, and no CYP51 sequence variation was identified among isolates of the same species. However, five N. meliosmae-myrianthae isolates grew on leaf discs treated at 10 µg/ml tebuconazole, and these were further exposed to tebuconazole selection pressure. Tebuconazole-adapted laboratory isolates of N. meliosmae-myrianthae showed an eight- to 25-fold increase in resistance after four rounds of selection that was not associated with CYP51 target alterations. In comparison with sensitive isolates, CYP51 expression was induced in the presence of tebuconazole in three out of four tebuconazole-adapted isolates tested. These results suggest a potential risk for QoI and DMI resistance development in Neophysopella spp.
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Affiliation(s)
- Ricardo F Santos
- Department of Plant Pathology and Nematology, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, São Paulo, 13418-900, Brazil
| | - Lilian Amorim
- Department of Plant Pathology and Nematology, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, São Paulo, 13418-900, Brazil
| | - Ana K M Wood
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
| | - Líllian B J Bibiano
- Department of Plant Pathology and Nematology, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba, São Paulo, 13418-900, Brazil
| | - Bart A Fraaije
- Biointeractions and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom
- National Institute of Agricultural Botany, Cambridge, Cambridgeshire, CB3 0LE, United Kingdom
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Kunova A, Pizzatti C, Saracchi M, Pasquali M, Cortesi P. Grapevine Powdery Mildew: Fungicides for Its Management and Advances in Molecular Detection of Markers Associated with Resistance. Microorganisms 2021; 9:1541. [PMID: 34361976 PMCID: PMC8307186 DOI: 10.3390/microorganisms9071541] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/14/2021] [Accepted: 07/17/2021] [Indexed: 11/17/2022] Open
Abstract
Grapevine powdery mildew is a principal fungal disease of grapevine worldwide. Even though it usually does not cause plant death directly, heavy infections can lead to extensive yield losses, and even low levels of the disease can negatively affect the quality of the wine. Therefore, intensive spraying programs are commonly applied to control the disease, which often leads to the emergence and spread of powdery mildew strains resistant to different fungicides. In this review, we describe major fungicide classes used for grapevine powdery mildew management and the most common single nucleotide mutations in target genes known to confer resistance to different classes of fungicides. We searched the current literature to review the development of novel molecular methods for quick detection and monitoring of resistance to commonly used single-site fungicides against Erysiphe necator. We analyze and compare the developed methods. From our investigation it became evident that this research topic has been strongly neglected and we hope that effective molecular methods will be developed also for resistance monitoring in biotroph pathogens.
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Affiliation(s)
- Andrea Kunova
- Department of Food, Environmental and Nutritional Science (DeFENS), University of Milan, Via Celoria 2, 20133 Milan, Italy; (C.P.); (M.S.); (M.P.); (P.C.)
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Fantastic Downy Mildew Pathogens and How to Find Them: Advances in Detection and Diagnostics. PLANTS 2021; 10:plants10030435. [PMID: 33668762 PMCID: PMC7996204 DOI: 10.3390/plants10030435] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/11/2021] [Accepted: 02/15/2021] [Indexed: 12/26/2022]
Abstract
Downy mildews affect important crops and cause severe losses in production worldwide. Accurate identification and monitoring of these plant pathogens, especially at early stages of the disease, is fundamental in achieving effective disease control. The rapid development of molecular methods for diagnosis has provided more specific, fast, reliable, sensitive, and portable alternatives for plant pathogen detection and quantification than traditional approaches. In this review, we provide information on the use of molecular markers, serological techniques, and nucleic acid amplification technologies for downy mildew diagnosis, highlighting the benefits and disadvantages of the technologies and target selection. We emphasize the importance of incorporating information on pathogen variability in virulence and fungicide resistance for disease management and how the development and application of diagnostic assays based on standard and promising technologies, including high-throughput sequencing and genomics, are revolutionizing the development of species-specific assays suitable for in-field diagnosis. Our review provides an overview of molecular detection technologies and a practical guide for selecting the best approaches for diagnosis.
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