Differential gene expression in ripe mango fruit (Mangifera indica L. cv. Azúcar) that favors the pathogenicity of the endophyte Colletotrichum tropicale

Andres Quintero- Mercado^1,2*Sebastián Rojas³Yordan Romero⁴Luis Fernando Lozano⁴Mario Serrano⁴Celsa Garcia¹

• ¹Departamento de Agronomía, Universidad Nacional de Colombia, Facultad de Ciencias Agrarias, Bogotá, Colombia
• ²Universidad del Magdalena, Facultad de Ingeniería, Santa Marta, Colombia
• ³Universidad Nacional de Colombia, Facultad de Ciencias, Departamento de Biología, Bogotá, Colombia
• ⁴Universidad Nacional Autonoma de Mexico Centro de Ciencias Genomicas, Cuernavaca, Mexico

Colletotrichum tropicale is an endophyte that has been reported as a pathogen in ripe mango fruits (cv. Azúcar) in Magdalena (Colombia), causing anthracnose. However, gene expression in the host that promotes its lifestyle transition remains unknown. This study aimed to analyze gene expression during the ripe mango fruit cv. Azúcar-C. tropicale endophyte interaction to identify differentially expressed host genes that facilitate the pathogen's infection process. An RNA-seq analysis was conducted at 0 and 12 hours post inoculation (hpi), including de novo assembly and bioinformatic functional annotation using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). A total of 5,435 differentially expressed genes (DEGs) were identified in the interaction, of which only 421 DEGs were detected in ripe mango fruits. Among these, 379 were upregulated and 42 were downregulated (T0 vs. T12 hpi). GO functional annotation of downregulated fruit genes revealed that the molecular functions affected at 12 hpi were related to the plant's defensive oxidative burst mediated by ROS (NADPH oxidase with hydrogen peroxide formation, peroxidases and oxidoreductase enzymes), while upregulated genes were associated with stress response, defense, transferase activity, and kinase activity. KEGG analysis identified pathways related to MAPK signaling, PAMP-triggered immunity, and phenylalanine metabolism. In conclusion, ripe mango fruit cv. Azúcar activates a defense response against C. tropicale at 12 hpi that does not overcome the pathogen's initial quiescent phase but instead facilitates conditions for its establishment by suppressing oxidative burst pathways, which may later contribute to oxidative stress during the necrotrophic phase.