Mariana Herrera Corzo (she/her/hers)
PhD candidate
University of Florida, Department of Plant Pathology
Gainesville, Florida, United States
Ina Schlathoelter
Postdoc
University of Florida, Department of Plant Pathology
Gainesville, Florida, United States
Adriana Arciniegas-Leal
Consultora/Investigadora
Centro Agronómico Tropical de Investigación y Enseñanza
Turrialba, Cartago, Costa Rica
Joshua Konkol
Postdoc
University of Florida, Department of Plant Pathology
Gainesville, Florida, United States
Sara M. Green
Biological Scientist II
University of Florida, Department of Plant Pathology
Gainesville, Florida, United States
Andrew J. Gitto
University of Florida, Department of Plant Pathology
Gainesville, Florida, United States
Alina S. Puig, PhD
USDA Agricultural Research Service, Foreign Disease – Weed Science Research Unit
Fort Detrick, MD, USA
Yeirme Y. Jaimes Suárez
Investigadora Asociada
Corporación Colombiana de Investigación Agropecuaria (Agrosavia)
Rionegro, Santander, Colombia
Bryan A. Bailey
Retired Research Plant Pathologist
USDA ARS, Beltsville, MD
Beltsville, Maryland, United States
Romina Umaharan
Pathology Team Leader
University of the West Indies, Cocoa Research Center
St. Augustine, Chaguanas, Trinidad and Tobago
Shamala Sundram
Group Leader Integrated Ganoderma Management
Malaysian Palm Oil Board
Bandar Baru Bangi, Selangor, Malaysia
David I. Guest
Professor
University of Sydney, Plant Pathology
Sydney, New South Wales, Australia
Oluwaseun O. Kolawole
Postdoc
University of Kentucky, Department of Plant Pathology
Lexington, Kentucky, United States
Dayana Rodezno
Associate Scientist Genetics
Mars Inc. MW Science & Technology
Davis, California, United States
Derek R. Drost
Global Director Cocoa Genetics & Breeding
Mars Inc, MW Science & Technology
Davis, California, United States
Jean-Philippe Jean-Philippe Marelli
Sr Director Integrated Pest Management
Mars Inc. MW Science & Technology
Davis, California, United States
Jeremy T. Brawner, PhD
Courtesy Faculty
University of Florida, Department of Plant Pathology
Gainesville, Florida, United States
Erica M. Goss, PhD
Professor
University of Florida, Department of Plant Pathology
Gainesville, Florida, United States
Phytophthora palmivora and P. megakarya are the primary causal agents of black pod disease in cacao (Theobroma cacao). While P. palmivora has a worldwide distribution, a broad host range, and can cause cacao yield losses of up to 30%, P. megakarya is restricted to West and Central Africa and is generally more aggressive on cacao, causing up to 90% loss if not controlled. Understanding the virulence mechanisms and genetic variation in these pathogens is essential for improving disease management for host resistance. This study integrates targeted capture and dual-RNA sequencing. Using probe sets for targeted capture of over 2,000 genes, we analyzed virulence gene variation in 72 P. palmivora and 67 P. megakarya isolates. Conserved effectors, including RxLR and CRN proteins, were identified. Dual RNA-seq of cacao pods at 12- and 48-hour post-inoculation using one isolate per species identified differentially expressed genes in 10 clones, from a germplasm collection, with varying susceptibility-resistance profiles. Pathogen transcript recovery was highest at 48 hours, highlighting key virulence genes active during infection. Using these expression data, we selected specific genes and examined sequence variations that could cause differential phenotypic responses. By integrating targeted sequencing with expression profiles, we identified genes essential for host colonization and compared their variation between P. palmivora and P. megakarya. This approach is a first step toward identifying key virulence factors of each species while infecting cacao.