Phylogenomic analysis of non-ribosomal peptide synthetases in the genus &i&Aspergillus&/i&.

摘要

Fungi from the genus &i&Aspergillus&/i& are important saprophytes and opportunistic human fungal pathogens that contribute in these and other diverse ways to human well-being. Part of their impact on human well-being stems from the production of small molecular weight secondary metabolites, which may contribute to the ability of these fungi to cause invasive fungal infections and allergic diseases. In this study, we identified one group of enzymes responsible for secondary metabolite production in five &i&Aspergillus&/i& species, the non-ribosomal peptide synthetases (NRPS). Hidden Markov models were used to search the genome databases of &i&A. fumigatus&/i&, &i&A. flavus&/i&, &i&A. terreus&/i&, &i&A. nidulans&/i&, and &i&A. oryzae&/i& for domains conserved in NRPS proteins. A genealogy of adenylation domains was utilized to identify orthologous and unique NRPS among the &i&Aspergillus&/i& species examined, as well as gain an understanding of the potential evolution of &i&Aspergillus&/i& NRPS. mRNA abundance of the 14 NRPS identified in the &i&A. fumigatus&/i& genome was analyzed using real-time reverse transcriptase PCR in different environmental conditions to gain a preliminary understanding of the possible functions of the NRPSs' peptide products. Our results suggest that &i&Aspergillus&/i& species contain conserved and unique NRPS genes with a complex evolutionary history. This result suggests that the genus &i&Aspergillus&/i& produces a substantial diversity of non-ribosomally synthesized peptides. Further analysis of these genes and their peptide products may identify important roles for secondary metabolites produced by NRPS in &i&Aspergillus&/i& physiology, ecology, and fungal pathogenicity.