Phylogeography, origin, and population structure of the self-fertile emerging plant pathogen Phytophthora pseudosyringae

Authors: MULLETT, MARTIN - Mendel University; HARRIS, ANNA - Forest Research; SCANU, BRUNO - University Of Sassari; VAN POUCKE, KRIS - Flanders Research Institute For Agriculture; LEBOLDUS, JARED - Oregon State University; STAMM, ELIZABETH - Oregon State University; Bourret, Tyler; CHRISTOVA, PETYA - Agrobioinstitute; OLIVA, JONAS - Universitat De Lleida; REDONDO, MIGUEL - Mid Sweden University; TALGO, VENCHE - Norwegian Institute Of Bioeconomy Research(NIBIO); CORCOBADO, TAMARA - Mendel University; MILENKOVIC, IVAN - Mendel University; HORTA JUNG, MARÍLIA - Mendel University; WEBBER, JOAN - Forest Research; HEUNGENS, KURT - Flanders Research Institute For Agriculture; JUNG, THOMAS - Mendel University

Submitted to: Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2024
Publication Date: 4/8/2024
Citation: Mullett, M.S., Harris, A.R., Scanu, B., Van Poucke, K., Leboldus, J., Stamm, E., Bourret, T.B., Christova, P.K., Oliva, J., Redondo, M.A., Talgo, V., Corcobado, T., Milenkovic, I., Horta Jung, M., Webber, J., Heungens, K., Jung, T. 2024. Phylogeography, origin, and population structure of the self-fertile emerging plant pathogen Phytophthora pseudosyringae. Molecular Plant Pathology. 25(4):e13450. https://doi.org/10.1111/mpp.13450.
DOI: https://doi.org/10.1111/mpp.13450

Interpretive Summary: Phytophthora is a genus of plant pathogens that pose grave threats to plants growing in agriculture, horticulture and natural ecosystems. Phytophthora pseudosyringae has been implicated in many disease outbreaks in Europe, North America and South America, but no one knows where the species originated. DNA analysis was used with a worldwide population of the species to answer this question. Results suggest that the species is ultimately native to Europe but was historically moved to North America. Since then, there has been movement of the pathogen in both directions. This information will be used by plant pathologists, regulatory officials and others involved in managing disease caused by P. pseudosyringae and preventing future introductions of this important plant pathogen.

Technical Abstract: Phytophthora pseudosyringae is a self-fertile pathogen of woody plants, particularly associated with tree species from the genera Fagus, Notholithocarpus, Nothofagus and Quercus, which is found across Europe and in parts of North America and Chile. It can behave as a soil pathogen infecting roots and the stem collar region, as well as an aerial pathogen infecting leaves, twigs and stem barks, causing particular damage in the United Kingdom and western North America. The population structure, migration and potential outcrossing of a worldwide collection of isolates were investigated using genotyping-by-sequencing. Coalescent-based migration analysis revealed that the North American population originated from Europe. Historical gene flow has occurred between the continents in both directions to some extent, yet contemporary migration is overwhelmingly from Europe to North America. Two broad population clusters dominate the global population of the pathogen, with a subgroup derived from one of the main clusters found only in western North America. Index of association and network analyses indicate an influential level of outcrossing has occurred in this preferentially inbreeding, homothallic oomycete. Outcrossing between the two main population clusters has created distinct subgroups of admixed individuals which are, however, less common than the main population clusters. Differences in life history traits between the two main population clusters should be further investigated together with virulence and host range tests to evaluate the risk each population poses to natural environments worldwide.