Unraveling microbial endosymbiosis dynamics in plant-parasitic nematodes with a genome skimming strategy

Authors: WASALA, S - Oregon State University; Hesse, Cedar; Wram, Catherine; HOWE, D - Oregon State University; Zasada, Inga; DENVER, D - Oregon State University

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2023
Publication Date: 10/20/2023
Citation: Wasala, S., Hesse, C.N., Wram, C.L., Howe, D.K., Zasada, I.A., Denver, D.R. 2023. Unraveling microbial endosymbiosis dynamics in plant-parasitic nematodes with a genome skimming strategy. Journal of Applied Microbiology. 3(4):1229-1248. https://doi.org/10.3390/applmicrobiol3040085.
DOI: https://doi.org/10.3390/applmicrobiol3040085

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that cause $100 billion dollars in global crop losses annually. There is a need to discover new ways to manage plant-parasitic nematodes. Endosymbionts, microbes that live within a host, have been shown to be targets for the management of insects and nematode parasites of humans. The focus of this research was endosymbiont discovery in plant-parasitic nematodes. It was discovered that endosymbionts are not present in all plant-parasitic nematodes; rather, they appear to be nematode specific. This research will be used by scientist to continue to explore the role of endosymbionts in plant-parasitic nematodes and may lead to the development of novel management strategies to combat nematode pests of agriculture.

Technical Abstract: Managing disease-causing parasites through the manipulation of their microbial symbionts is an appealing biological control strategy that is increasingly deployed in many animal and plant parasite systems. Bacterial endosymbionts, such as Wolbachia and Cardinium, infect a wide range of arthropods and are known to occur in some nematode groups. The extent and diversity of Wolbachia and Cardinium endosymbionts in nematodes, however, remains unclear. In this study, a genome skimming approach was used to investigate Wolbachia and Cardinium occurrence in diverse plant-parasitic nematodes, including 52 nematode populations representing 12 different species. The study explored the application of genome skimming in applied microbiology, with a primary emphasis on revealing microbial symbioses and providing further insights into endosymbiont diversity. Of the 52 samples analyzed, strong genomic evidence for Wolbachia and Cardinium was observed in five and one plant-parasitic nematde sample(s), respectively, suggesting a limited occurrence of Wolbachia and Cardinium across species. Strong evidence for Wolbachia was found in Pratylenchus penetrans and Radopholus similis populations obtained from North America, South America and Africa. Strong evidence for Cardinium was found in Heterodera glycines population obtained from North America. The study also provided weak genomic evidence for Wolbachia occurrence in Globodera pallida, Meloidogyne incognita, Rotylenchus reniformis, Pratylechus coffeae, Pratylenchus neglectus, and Pratylenchus thornei. Weak genomic evidence for Cardinium was found in G. pallida, R. reniformis and P. neglectus. Almost all of these nematode species were previously unreported as carriers of these microbial endosymbionts, and could benefit from further in-depth analysis and validation. The detection of Wolbachia and Cardinium in some, but not all, populations analyzed within a given nematode species suggests that neither endosymbiont is an obligate mutualist in plant-parasitic nematode hosts. This work significantly advanced our understanding of plant-parasitic nematode-bacteria symbioses and diversity.