Samuel Osabutey

My research focuses on understanding the evolutionary and ecological mechanisms driving the emergence of bacterial plant pathogens, with particular emphasis on Pseudomonas syringae pv. aptata, the causal agent of bacterial leaf spot in table beet, Swiss chard, and several cucurbit crops. P. syringae pv. aptata is a genetically diverse pathogen within the P. syringae species complex, which includes both pathogenic and non-pathogenic strains that coexist on plant surfaces and in seeds. The emergence of novel, more virulent lineages poses significant challenges to vegetable and seed production worldwide.

I investigate how horizontal gene transfer contributes to the evolution of new pathogen lineages and whether these genetic exchange events are influenced by the host environment, particularly differences in cultivar resistance and susceptibility. My research examines the movement of mobile genetic elements, including effectors, pathogenicity islands, plasmids, copper resistance genes, and other virulence-associated genes, among P. syringae populations and between members of the plant-associated microbiome. In addition, I study how the phytobiome shapes pathogen evolution by characterizing microbial communities associated with leaves and identifying genetic reservoirs that may facilitate the acquisition of adaptive traits. I am particularly interested in determining whether non-pathogenic P. syringae strains can acquire virulence genes through horizontal gene transfer and evolve into pathogenic lineages with specificity toward particular host plants.

By integrating plant pathology, microbial ecology, comparative genomics, and microbiome science, my research seeks to uncover the mechanisms underlying pathogen emergence and adaptation. Ultimately, I aim to generate knowledge that supports the development of durable host resistance, improved disease surveillance, and sustainable management strategies to reduce the emergence and spread of bacterial plant diseases.

Publications 

• Hamidizade, M., Smith, A. C., Osabutey, S., Potnis, N., & Bull, C. T. (2026). A Genome-Anchored TaqMan^TM qPCR Assay for the Specific Detection of an Aggressive Genotype of Pseudomonas syringae pv. aptata. Plant Disease (10.1094/PDIS-03-26-0442-RE).
• Mensah, M. K., Osabutey, S., Agyei, A., & Nyaku, S. T. (2026). In-vitro nematicidal efficacy of aqueous leaf and root extracts from indigenous Ghanaian plants on Meloidogyne incognita egg hatch. African Crop Science Journal, 34(4), 891-900.

• Bull, C. T., Crane, S., Nampijja, M., Falcone, N., Bibi, S., García-Rodríguez, R., Hamidizade, M., Smith, C., Pena MacLellan, M., Osabutey, S., Safni, I., Herschlag, R., Potnis, N., & du Toit, L. J. (2025, August). Diversity of seedborne Pseudomonas syringae pv. aptata isolates associated with bacterial leaf spot of table beet and Swiss chard [Conference poster]. Plant Health 2025. https://www.pseudosonseed.org/wp-content/uploads/Bull-Plant-Health-2025-FINAL.pdf

• Eze, C. N., Hassan, J. I., Ibeh, R. C., Igboeli, C. N., Osabutey, S., & Kehinde, O. D. (2025, September 18). Genotype-by-environment interactions in transgenic crops: A critical review of gene function validation under variable agronomic conditions. Journal of Environment, Climate, and Ecology. https://journals.stecab.com/jece/article/view/1021

• Osabutey, S., Pethybridge, S., Goldman, I., & Bull, C. T. (2025). Virulence and aggressiveness of diverse Pseudomonas syringae pv. aptata strains on resistant and susceptible table beet and Swiss chard cultivars [Conference poster]. Plant Health 2025. https://www.pseudosonseed.org/wp-content/uploads/Osabutey-Plant-Health-2025-Final.pdf

• Eze, C. N., Ibeh, R. C., Hassan, J. I., & Osabutey, S. (2025). Phenotypic analysis and characterization methods for transgenic Setaria viridis: From morphology to molecular markers: A comprehensive review. Journal of Agriculture, Aquaculture, and Animal Science, 2(2), 53–65. https://doi.org/10.69739/jaaas.v2i2.809
• Honger, J. O., Ofoe, R., Osabutey, S., & Abbey, A. A. (2024). Importance, etiology and management of the bacterial black spot disease of mango. Indian Phytopathology, 77(3), 681-691.
• Honger, J. O., Ofoe, R., Osabutey, S., & Abbey, A. A. (2024). Importance, etiology, and management of the bacterial black spot disease of mango. Indian Phytopathology, 77(3), 681-691.
• Enchill, A. K., Nyaku, S. T., Osabutey, S., Lutuf, H., & Cornelius, E. W. (2023). Prevalence of yam nematodes in diverse soil communities, and their morphometrics in the Krachi-Nchumuru District of Ghana. African Crop Science Journal, 31(3), 319–336. https://doi.org/10.4314/acsj.v31i3.4
• Agyapong, A. F., Ofoe, R., Darkwa, E., Eleblu, S. Y.,  Pangariyi, B., Osabutey, S., Eleblu, J. S. Y. (2023). Detection, Identification and Management of Seed-borne fungal Pathogens on Farmer-Saved Soybean (Glycine max (L.) Merrill) seeds in Ghana. Science and Development Journal, 7(2), 123-123.
• Nyaku, S. T., Lutuf, H., Honger, J. O., Dede, A., Brentu, F. C., Benissan, R., Osabutey, S., Larbi, V., Koranteng, E., Afun, C., Okyere, M., & Ablormeti, F. K. (2021). Prevalence of plant-parasitic nematodes in rice fields in Ghana. African Crop Science Journal, 29(4), 471–482. https://doi.org/10.4314/acsj.v29i4.4
• Honger, J. O., Osabutey, S., Nyaku, S. T., & Lambon, J. B. (2021). Molecular characterization, pathogenicity and copper sensitivity of Xanthomonas citri pv. mangiferaeindicae, the causal agent of mango bacterial black spot disease in Ghana. Archives of Phytopathology and Plant Protection, 54(19–20), 1703–1721. https://doi.org/10.1080/03235408.2021.193699

Grants and Awards

• Lester P. Nichols Memorial Award for the 2026–2027, College of Agricultural Sciences scholarship recipient (2026/2027 ). Recognition of outstanding research accomplishments by a graduate degree candidate in Plant Pathology. 
• American Phytopathology Society-FoundationRaymon G. Grogan Student Travel Fund (June, 2025)
• James F. & Marilyn L. Tammen Memorial Endowment for International Plant Pathology (June, 2025)
• CAS Graduate Student Travel Awards by Sahakian Endowment (April, 2025)
• University Park Allocation Committee (UPAC) travel award (June, 2025)
• G. Leventis Scholarship Award for Graduate Studies, University of Ghana (2018/2019 Academic year).