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The hop downy mildew pathogen Pseudoperonospora humuli

Pseudoperonospora humuli is an obligate biotrophic oomycete that causes downy mildew, one of the most devastating diseases of cultivated hop, Humulus lupulus. Downy mildew occurs in all production areas of the crop in the Northern Hemisphere and Argentina. The pathogen overwinters in hop crowns and...

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Autores principales: Purayannur, Savithri, Gent, David H., Miles, Timothy D., Radišek, Sebastjan, Quesada‐Ocampo, Lina M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232024/
https://www.ncbi.nlm.nih.gov/pubmed/33942461
http://dx.doi.org/10.1111/mpp.13063
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author Purayannur, Savithri
Gent, David H.
Miles, Timothy D.
Radišek, Sebastjan
Quesada‐Ocampo, Lina M.
author_facet Purayannur, Savithri
Gent, David H.
Miles, Timothy D.
Radišek, Sebastjan
Quesada‐Ocampo, Lina M.
author_sort Purayannur, Savithri
collection PubMed
description Pseudoperonospora humuli is an obligate biotrophic oomycete that causes downy mildew, one of the most devastating diseases of cultivated hop, Humulus lupulus. Downy mildew occurs in all production areas of the crop in the Northern Hemisphere and Argentina. The pathogen overwinters in hop crowns and roots, and causes considerable crop loss. Downy mildew is managed by sanitation practices, planting of resistant cultivars, and fungicide applications. However, the scarcity of sources of host resistance and fungicide resistance in pathogen populations complicates disease management. This review summarizes the current knowledge on the symptoms of the disease, life cycle, virulence factors, and management of hop downy mildew, including various forecasting systems available in the world. Additionally, recent developments in genomics and effector discovery, and the future prospects of using such resources in successful disease management are also discussed. TAXONOMY: Class: Oomycota; Order: Peronosporales; Family: Peronosporaceae; Genus: Pseudoperonospora; Species: Pseudoperonospora humuli. DISEASE SYMPTOMS: The disease is characterized by systemically infected chlorotic shoots called “spikes". Leaf symptoms and signs include angular chlorotic lesions and profuse sporulation on the abaxial side of the leaf. Under severe disease pressure, dark brown discolouration or lesions are observed on cones. Infected crowns have brown to black streaks when cut open. Cultivars highly susceptible to crown rot may die at this phase of the disease cycle without producing shoots. However, foliar symptoms may not be present on plants with systemically infected root systems. INFECTION PROCESS: Pathogen mycelium overwinters in buds and crowns, and emerges on infected shoots in spring. Profuse sporulation occurs on infected tissues and sporangia are released and dispersed by air currents. Under favourable conditions, sporangia germinate and produce biflagellate zoospores that infect healthy tissue, thus perpetuating the infection cycle. Though oospores are produced in infected tissues, their role in the infection cycle is not defined. CONTROL: Downy mildew on hop is managed by a combination of sanitation practices and timely fungicide applications. Forecasting systems are used to time fungicide applications for successful management of the disease. USEFUL WEBSITES: https://content.ces.ncsu.edu/hop‐downy‐mildew (North Carolina State University disease factsheet), https://www.canr.msu.edu/resources/michigan‐hop‐management‐guide (Michigan Hop Management Guide), http://uspest.org/risk/models (Oregon State University Integrated Plant Protection Center degree‐day model for hop downy mildew), https://www.usahops.org/cabinet/data/Field‐Guide.pdf (Field Guide for Integrated Pest Management in Hops).
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spelling pubmed-82320242021-06-29 The hop downy mildew pathogen Pseudoperonospora humuli Purayannur, Savithri Gent, David H. Miles, Timothy D. Radišek, Sebastjan Quesada‐Ocampo, Lina M. Mol Plant Pathol Pathogen Profile Pseudoperonospora humuli is an obligate biotrophic oomycete that causes downy mildew, one of the most devastating diseases of cultivated hop, Humulus lupulus. Downy mildew occurs in all production areas of the crop in the Northern Hemisphere and Argentina. The pathogen overwinters in hop crowns and roots, and causes considerable crop loss. Downy mildew is managed by sanitation practices, planting of resistant cultivars, and fungicide applications. However, the scarcity of sources of host resistance and fungicide resistance in pathogen populations complicates disease management. This review summarizes the current knowledge on the symptoms of the disease, life cycle, virulence factors, and management of hop downy mildew, including various forecasting systems available in the world. Additionally, recent developments in genomics and effector discovery, and the future prospects of using such resources in successful disease management are also discussed. TAXONOMY: Class: Oomycota; Order: Peronosporales; Family: Peronosporaceae; Genus: Pseudoperonospora; Species: Pseudoperonospora humuli. DISEASE SYMPTOMS: The disease is characterized by systemically infected chlorotic shoots called “spikes". Leaf symptoms and signs include angular chlorotic lesions and profuse sporulation on the abaxial side of the leaf. Under severe disease pressure, dark brown discolouration or lesions are observed on cones. Infected crowns have brown to black streaks when cut open. Cultivars highly susceptible to crown rot may die at this phase of the disease cycle without producing shoots. However, foliar symptoms may not be present on plants with systemically infected root systems. INFECTION PROCESS: Pathogen mycelium overwinters in buds and crowns, and emerges on infected shoots in spring. Profuse sporulation occurs on infected tissues and sporangia are released and dispersed by air currents. Under favourable conditions, sporangia germinate and produce biflagellate zoospores that infect healthy tissue, thus perpetuating the infection cycle. Though oospores are produced in infected tissues, their role in the infection cycle is not defined. CONTROL: Downy mildew on hop is managed by a combination of sanitation practices and timely fungicide applications. Forecasting systems are used to time fungicide applications for successful management of the disease. USEFUL WEBSITES: https://content.ces.ncsu.edu/hop‐downy‐mildew (North Carolina State University disease factsheet), https://www.canr.msu.edu/resources/michigan‐hop‐management‐guide (Michigan Hop Management Guide), http://uspest.org/risk/models (Oregon State University Integrated Plant Protection Center degree‐day model for hop downy mildew), https://www.usahops.org/cabinet/data/Field‐Guide.pdf (Field Guide for Integrated Pest Management in Hops). John Wiley and Sons Inc. 2021-05-04 /pmc/articles/PMC8232024/ /pubmed/33942461 http://dx.doi.org/10.1111/mpp.13063 Text en © 2021 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd. https://creativecommons.org/licenses/by-nc/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
spellingShingle Pathogen Profile
Purayannur, Savithri
Gent, David H.
Miles, Timothy D.
Radišek, Sebastjan
Quesada‐Ocampo, Lina M.
The hop downy mildew pathogen Pseudoperonospora humuli
title The hop downy mildew pathogen Pseudoperonospora humuli
title_full The hop downy mildew pathogen Pseudoperonospora humuli
title_fullStr The hop downy mildew pathogen Pseudoperonospora humuli
title_full_unstemmed The hop downy mildew pathogen Pseudoperonospora humuli
title_short The hop downy mildew pathogen Pseudoperonospora humuli
title_sort hop downy mildew pathogen pseudoperonospora humuli
topic Pathogen Profile
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232024/
https://www.ncbi.nlm.nih.gov/pubmed/33942461
http://dx.doi.org/10.1111/mpp.13063
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