Modelling Cocoa-Phytophthora Megakarya (causal agent of the black pod disease) Metabolic Interaction to weaken Plant-Host Compatible Relationship

• Applicant: Dr. Christian Gaele Nembot Fomba
• Subject Area: Plant Breeding and Plant Pathology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 558701390

Cocoa (Theobroma cacao L.) is an important cash crop in West and Central Africa; however, it is constantly under threat from various pests and diseases, including Phytophthora megakarya, a soil-borne oomycete that causes black pod disease. Phytophthora megakarya poses a major threat to farmers' livelihood and economic growth of producing countries, and although various control measures have been implemented, sustained success has been limited. Emergence of resistant cultivars would be a significant step towards effective control of the disease, and a strategy for achieving this goal is by understanding the metabolic interaction between the plant and the pathogen. To date, the metabolic interactions between the host and the pathogen during infection have hardly been studied and their interlinked metabolism remains poorly understood. However, gaining a quantitative understanding of nutrient exchanges in the host-pathogen system will be the prerequisite for suggesting intervention strategies for improved pathogen resistance. To tackle this question, we propose to analyse the metabolic interactions between cocoa and its pathogen by reconstructing metabolic models for both cocoa (Theobroma cacao L) and P. megakarya and by integrating them to simulate metabolic exchanges between the host and the pathogen. Our results will provide insight into the metabolic processes driving the host-pathogen interaction and reveal key potential targets for disrupting this interaction. This analysis shall guide metabolic engineers and plant breeders in generating new varieties of crops with weakened plant-pathogen compatibility and increased yield. The approach can be broadly applicable to other host-pathogen systems beyond cocoa and may have implications for sustainable agricultural practices.

• DFG Programme: WBP Position