Variations in banana susceptibility to crown rot disease have been observed but the molecular mechanisms underlying these quantitative host-pathogen relationships are still unknown. This study was designed to compare gene expression between crowns of banana fruit showing a high susceptibility (S+) and crowns showing a low susceptibility (S-) to the disease. Comparisons were performed at two situation times: i) between crowns (S+ and S-) collected 1 h before inoculation and ii) between crowns (S+ and S-) collected 13 days after inoculation. Gene expression comparisons were performed with cDNA-amplified fragment length polymorphism (AFLP) and results were confirmed by realtime reverse-transcription polymerase chain reaction. Among genes identified as differentially expressed between S+ and S- crowns, two were involved in signal transduction, three in proteolytic machinery, two had similarity to pathogenesis- related protein 14, one to a CCR4-associated factor protein, and one to a cellulose synthase. Paradoxically, the overexpression of the cellulose synthase gene was associated with banana showing a high susceptibility in both preand post-inoculation situations. Finally, the cDNA-AFLP identified a gene that seems to be associated with the quantitative banana responses to crown rot disease; this gene encodes a dopamine-?-monooxygenase, which is involved in the catecholamine pathway. To our knowledge, this work is the first to address both pre- and post-infection gene expression with the same host-pathogen combination and distinct susceptibility levels.