Project description:The filamentous fungus Aspergillus oryzae is an important microbial cell factory for industrial production of useful enzymes, such as α-amylase. In order to optimize the industrial enzyme production process, there is a need to understand fundamental processes underlying protein production, here under how protein production links to metabolism through global regulatory structures. In this study, two α-amylase-producing strains of A. oryzae, a wild type strain and a transformant strain containing additional copies of the α-amylase gene, were characterized at a systematic level. Based on integrated analysis of ome-data together with genome-scale metabolic network and flux calculation, we identified key genes, key enzymes, key proteins, and key metabolites involved in the processes of protein synthesis and secretion, nucleotide metabolism, and amino acid metabolism that can be the potential targets for improving industrial protein production. Keywords: Two Aspergillus oryzae strains and two different carbon sources
Project description:The filamentous fungus Aspergillus oryzae is an important microbial cell factory for industrial production of useful enzymes, such as α-amylase. In order to optimize the industrial enzyme production process, there is a need to understand fundamental processes underlying protein production, here under how protein production links to metabolism through global regulatory structures. In this study, two α-amylase-producing strains of A. oryzae, a wild type strain and a transformant strain containing additional copies of the α-amylase gene, were characterized at a systematic level. Based on integrated analysis of ome-data together with genome-scale metabolic network and flux calculation, we identified key genes, key enzymes, key proteins, and key metabolites involved in the processes of protein synthesis and secretion, nucleotide metabolism, and amino acid metabolism that can be the potential targets for improving industrial protein production. Keywords: Two Aspergillus oryzae strains and two different carbon sources Two carbon sources (glucose, maltose) with three biological replicates for A. oryzae strain A1560 and strain CF1.1
Project description:The potential for sexual reproduction in Aspergillus oryzae was assessed by investigating the presence and functionality of MAT genes. Previous genome studies had identified a MAT1-1 gene in the RIB40 reference strain. We now report the existence of a complimentary MAT1-2 gene and sequencing of an idiomorph region from A. oryzae strain AO6. This allowed the development of a PCR diagnostic assay, which detected isolates of MAT1-1 and MAT1-2 genotype among 180 strains assayed including industrial tane-koji isolates. Strains used for sake and miso production showed a near 1:1 ratio of MAT1-1 and MAT1-2 mating-types, whereas strains used for soy sauce production showed a significant bias towards the MAT1-2 mating type. MAT1-1 and MAT1-2 isogenic strains were then created by genetic manipulation of the resident idiomorph, and comparisons were made of gene expression by DNA microarray and RT-PCR methodologies under conditions when MAT genes were expressed. 33 genes were found to be up-regulated greater than 10-fold in either the MAT1-1 host or MAT1-2 gene replacement strains relative to each other, showing that both MAT1-1 and MAT1-2 genes functionally regulate gene expression in A. oryzae in a mating-type dependent manner, the first such report from a supposedly asexual fungus. MAT1-1 expression specifically up-regulated an a-pheromone precursor gene, but most genes affected were of unknown function. Results are consistent with a heterothallic breeding system in A. oryzae, and prospects for the discovery of a sexual cycle are discussed.
Project description:The potential for sexual reproduction in Aspergillus oryzae was assessed by investigating the presence and functionality of MAT genes. Previous genome studies had identified a MAT1-1 gene in the RIB40 reference strain. We now report the existence of a complimentary MAT1-2 gene and sequencing of an idiomorph region from A. oryzae strain AO6. This allowed the development of a PCR diagnostic assay, which detected isolates of MAT1-1 and MAT1-2 genotype among 180 strains assayed including industrial tane-koji isolates. Strains used for sake and miso production showed a near 1:1 ratio of MAT1-1 and MAT1-2 mating-types, whereas strains used for soy sauce production showed a significant bias towards the MAT1-2 mating type. MAT1-1 and MAT1-2 isogenic strains were then created by genetic manipulation of the resident idiomorph, and comparisons were made of gene expression by DNA microarray and RT-PCR methodologies under conditions when MAT genes were expressed. 33 genes were found to be up-regulated greater than 10-fold in either the MAT1-1 host or MAT1-2 gene replacement strains relative to each other, showing that both MAT1-1 and MAT1-2 genes functionally regulate gene expression in A. oryzae in a mating-type dependent manner, the first such report from a supposedly asexual fungus. MAT1-1 expression specifically up-regulated an a-pheromone precursor gene, but most genes affected were of unknown function. Results are consistent with a heterothallic breeding system in A. oryzae, and prospects for the discovery of a sexual cycle are discussed. On a condition that induces mating-type genes descrived in growth protocol section, each cogenic MAT1-1 and MAT1-2 mating-type strains were processed into RNA extraction and hybridization on Affymetrix microarrays. In a speculation that genes involved in putative mating process were reguated in mating-type dependent manner, we designed the cogenic strains that differs only in mating-type gene locus to analyze differential gene expression of MAT1-1 vs MAT1-2 strains.
Project description:DNA methylation is an important epigenetic modification widespread in eukaryotes and bacteria. However, genomic methylation levels show a dramatic diversity throughout the evolution of life, varying even between closely-related species and strains. In Aspergillus, a genus of filamentous fungi, the existence of DNA methylation has been controversial with previous studies reporting different conclusions using different species and detection methods. Here, we report DNA methylation analysis of Aspergillus oryzae, an important species in the Japanese fermentation industry, and a close relative of the pathogen Aspergillus flavus whose DNA methylation has been denied by the recent previous study using bisulfite sequencing. In this study, we conduct bisulfite-seq and RNA-seq of A. oryzae using three biological replicates from each of liquid and solid culture conditions. The statistical analysis of these data reveals thousands of highly-confident methylated cytosines (mCs), while the re-analysis of data from A. flavus detects few mCs being consistent with the previous study. Based on the comparative genome analysis of A. oryzae and A. flavus, we find that a substantial fraction of mCs are observed in syntenic segments including the aflatoxin biosynthesis gene cluster. Together, our results are the first evidence of DNA methylation in A. oryzae, providing a new example of the evolutionary diversity of DNA methylation as well as a new insight into its industrial applications.
Project description:DNA methylation is an important epigenetic modification widespread in eukaryotes and bacteria. However, genomic methylation levels show a dramatic diversity throughout the evolution of life, varying even between closely-related species and strains. In Aspergillus, a genus of filamentous fungi, the existence of DNA methylation has been controversial with previous studies reporting different conclusions using different species and detection methods. Here, we report DNA methylation analysis of Aspergillus oryzae, an important species in the Japanese fermentation industry, and a close relative of the pathogen Aspergillus flavus whose DNA methylation has been denied by the recent previous study using bisulfite sequencing. In this study, we conduct bisulfite-seq and RNA-seq of A. oryzae using three biological replicates from each of liquid and solid culture conditions. The statistical analysis of these data reveals thousands of highly-confident methylated cytosines (mCs), while the re-analysis of data from A. flavus detects few mCs being consistent with the previous study. Based on the comparative genome analysis of A. oryzae and A. flavus, we find that a substantial fraction of mCs are observed in syntenic segments including the aflatoxin biosynthesis gene cluster. Together, our results are the first evidence of DNA methylation in A. oryzae, providing a new example of the evolutionary diversity of DNA methylation as well as a new insight into its industrial applications.
Project description:In this study, we achieved translocated chromosomal duplication and triplication of a 1.4-Mb targeted chromosomal region by directly introducing I-SceI meganuclease into A. oryzae protoplast cells. Strains with duplication and triplication of chromosome 2 showed substantial increases in the activity of protease and amylase. Gene dosage effects were enhanced by combining the structural gene and its regulatory gene, indicating that segmental duplications of chromosomes play important phenotypic roles in koji mold strains.
Project description:Aspergillus flavus and A. oryzae represent two unique species predicted to have spent centuries in vastly different environments. A. flavus is an important opportunistic plant pathogen known for contaminating crops with the carcinogenic mycotoxin, aflatoxin and A. oryzae is a domesticated fungus used in food fermentations. Remarkably, the genomes of these two species are still nearly identical. We have used the recently sequenced genomes of A. oryzae RIB40 and A. flavus NRRL3357 along with array based comparative genome hybridization (CGH) as a tool to compare genomes across several strains of these two species. A comparison of three strains from each species by CGH revealed only 42 and 129 genes unique to A. flavus and A. oryzae, respectively. Further, only 709 genes were identified as being polymorphic between the species. Despite the high degree of similarity between these two species, correlation analysis among all data from the CGH arrays for all strains used in this study reveals a species split. However, this view of species demarcation becomes muddled when focused on only those genes for secondary metabolism.