Revealing Diversity in NRPS Gene Clusters Across Six Pathogenic Colletotrichum Species

Secondary metabolites play a crucial role in fungal survival and pathogenicity, with non-ribosomal peptide synthetases (NRPSs) serving as key enzymes in the biosynthesis of many of these essential compounds. This study aimed to investigate the diversity and evolutionary relationships of NRPS gene clusters across six Colletotrichum species to better understand their roles in fungal pathogenicity. Using a combination of genomic analyses, we identified 53 unique NRPS genes and clusters, including species-specific genes, and categorized them into distinct functional clades. Of the 53 unique NRPSs encoded by the 6 Colletotrichum species, 9 are newly identified within the Colletotrichum genus and consist of multi-modular NRPSs featuring 2 and 4 modules. Phylogenetic analysis based on adenylation domains revealed that the NRPSs of the 6 Colletotrichum species are grouped into 16 distinct clades, each globally associated with biological functions, including apicidin synthetase, chrysogine, hydroxamate-type ferrichrome siderophore peptide synthetase, gliovirin, and other unclassified synthetases. Among the 15 identified gene clusters, one cluster containing the NRPS gene CfNRPS9 is unique to C. fructicola and is absent from all other Colletotrichum genomes. These findings offer valuable insights into the diversity and evolutionary pathways of NRPS gene clusters in pathogenic Colletotrichum species, highlighting their potential roles in pathogenicity and secondary metabolite production. The newly identified NRPSs present promising targets for future functional studies and the development of new strategies for managing diseases in crops affected by Colletotrichum species.