Comparative transcriptome analysis reveals pathogenic mechanisms of Colletotrichum gloeosporioides in figs (Ficus...

Colletotrichum gloeosporioides is a pathogen responsible for causing anthracnose in Ficus carica L. (figs) and other fruits worldwide. Various stages of infection have been reported in C. gloeosporioides hosts; however, the molecular mechanisms underlying the differences in pathogen pathogenicity remain poorly understood. In this study, two strains (K7 and M5) of C. gloeosporioides isolated from fig leaves were compared. The K7 strain exhibited higher pathogenicity, faster mycelium growth, and quicker spore germination than M5 strain. To investigate the reasons for these differences, RNA sequencing was performed on samples collected 24 h post-infection from fig-infected K7 and M5 strains (K7-fig and M5-fig). Mycelia grown for 24 h on PDA plates (K7 and M5) were used as controls. A total of 143 differentially expressed genes (DEGs) were identified in C. gloeosporioides during fig infection, 79 DEGs of which were shared between K7 and M5. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of these 143 DEGs revealed significant enrichment in five pathways: aflatoxin biosynthesis, sphingolipid metabolism, aminoacyl-tRNA biosynthesis, nitrogen metabolism and the mitogen-activated protein kinase (MAPK) signaling pathway. Among the shared 79 DEGs, significant enrichment was observed in nitrogen metabolism, pentose phosphate pathway and aflatoxin biosynthesis in the infection process. Notably, pathways related to sphingolipid metabolism, aminoacyl-tRNA biosynthesis and MAPK signaling pathway-yeast in K7 were distinct from those in M5 during fig infection. These findings suggest that the high virulence of K7 may be associated with toxins produced via sphingolipid metabolism, aminoacyl-tRNA biosynthesis and MAPK signaling pathway-yeast. Therefore, this study provides valuable insights into the pathogenic biology of C. gloeosporioides.