Sequencing of Aspergillus nidulans and comparative analysis with A. fumigatus and A. oryzae

Abstract

The aspergilli comprise a diverse group of filamentous fungi spanning over 200 million years of evolution. Here we report the genome sequence of the model organism Aspergillus nidulans, and a comparative study with Aspergillus fumigatus, a serious human pathogen, and Aspergillus oryzae, used in the production of sake, miso and soy sauce. Our analysis of genome structure provided a quantitative evaluation of forces driving long-term eukaryotic genome evolution. It also led to an experimentally validated model of mating-type locus evolution, suggesting the potential for sexual reproduction in A. fumigatus and A. oryzae. Our analysis of sequence conservation revealed over 5,000 non-coding regions actively conserved across all three species. Within these regions, we identified potential functional elements including a previously uncharacterized TPP riboswitch and motifs suggesting regulation in filamentous fungi by Puf family genes. We further obtained comparative and experimental evidence indicating widespread translational regulation by upstream open reading frames. These results enhance our understanding of these widely studied fungi as well as provide new insight into eukaryotic genome evolution and gene regulation. More than 300 labs worldwide are using the fungus Aspergillus nidulans as a model system for molecular genetics, and other species of this fungus are important in everyday life. A package of three genomics papers in this issue covers the Aspergillus field comprehensively. Galagan et al. report the genome sequence of the laboratory classic A. nidulans, and Nierman et al. have sequenced A. fumigatus, known chiefly as a human pathogen and allergen. And finally Machida et al. present genome sequencing and analysis of A. oryzae, focusing in particular on the expansion of genes in its genome, which is almost 25% bigger than the other two genomes. A. oryzae is used in traditional Chinese and Japanese food fermentation (think soy sauce) and also in enzyme production by biotechnologists.