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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #406599
Research Project: Diagnostics and Biological Approaches for Management of Emerging Oomycete Plant Pathogens

Location: Foreign Disease-Weed Science Research

Title: Single host plant species may harbour more than one species of Peronospora – a case study in Peronospora on Plantago

Author
item MU, MAN - Goethe University
item CHOI, YOUNG-JOON - Kunsan National University
item KRUSE, JULIA - Natural History Museum Of The Palatinate
item Crouch, Jo Anne
item PLOCH, SEBASTIAN - Senckenberg Biodiversity And Climate Research Centre
item THINES, MARCO - Goethe University

Submitted to: Persoonia: Molecular Phylogeny and Evolution of Fungi
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2023
Publication Date: 6/5/2024
Citation: Mu, M., Choi, Y., Kruse, J., Crouch, J., Ploch, S., Thines, M. 2024. Single host plant species may harbour more than one species of Peronospora – a case study in Peronospora on Plantago. Persoonia: Molecular Phylogeny and Evolution of Fungi. 94-118. https://doi.org/10.3767/persoonia.2024.52.04.
DOI: https://doi.org/10.3767/persoonia.2024.52.04

Interpretive Summary: Destructive downy mildew diseases are an increasingly difficult problem for numerous horticultural and crop plants. Many are newly discovered, which means that the identity of the disease-causing organism is not known. This research used DNA sequences and physical traits to identify and give names to eleven new species of downy mildew molds infecting Plantago, a group of plants that is used for ornamental and medicinal purposes. This research is significant because it is the first time that the organisms causing these diseases have been identified. This is also a rare situation when a downy mildew disease on a single host plant has been caused by four different water mold species. This is important because host range is commonly used as a way to identify downy mildew species; these new results show this practice likely to yield unreliable results. This new information will allow plant pathologists, horticulturalists and diagnostic laboratories to accurately identify these new plant pathogens. These findings will also be useful to plant regulatory officials working to control the spread of downy mildew diseases.

Technical Abstract: The genus Peronospora is the largest genus of the oomycetes, fungus-like members of the kingdom Straminipila that also contains amoeboid (e.g., Leukarachnion) and plant-like (e.g., Laminaria) lifeforms. Peronospora species are obligate biotrophic plant pathogens, causing high economic losses in various crops and ornamentals, including Plantago species. Several species of Plantago are used as speciality crops and medicinal plants. In this study, Peronospora species parasitic on Plantago were investigated based on morphology and phylogenetic analyses using two nuclear (ITS, nrLSU) loci and one mitochondrial (cox2) locus. As a result of these investigations, eleven new species are added to the already known Peronospora species on Plantago. Interestingly, it was found that four independent species are parasitic to Plantago major, highlighting that the reliance on the host plant for pathogen determination can be misleading in Peronospora. Taking this into account, morphological and phylogenetic analyses should be conducted as a prerequisite for effective quarantine regulations and phytosanitary measures.