Project description:A koji mold Aspergillus kawachii is used for making a Japanese distilled spirit, shochu. During making shochu, A. kawachii is grown in a solid-state culture comprised of steamed grains such as rice or barley, termed koji, to convert the starch to glucose and also to produce citric acid. During this process, cultivation temperature of A. kawachii is generally controlled by raising to 40M-BM-0C and then lowering to 30M-BM-0C. The cultivation at 40M-BM-0C and the following at lower temperature of 30M-BM-0C has important roles in the elevated activity of amylase and starting an accumulation of a large amount of citric acid, respectively. In this study, we investigated the effect of temperature on the gene expression of A. kawachii when barley was used as ingredient for making koji. The results of DNA microarray and gene ontology analysis showed that the expression of genes involved in the metabolic processes of glycerol, trehalose, and pentose phosphate that branch from glycolysis was down-regulated by shifting the cultivation temperature from 40M-BM-0C from 30M-BM-0C. In addition, reduction in the expression of the genes related with heat shock responses and increasing in the expression of the genes related with amino acid transport after the temperature lowering were found to be significant change. These results suggested that the cultivation at 40M-BM-0C is stressful event for the A. kawachii and the heat adaption lead to the depression of citric acid accumulation through activation of the branching pathways from glycolysis. The gene expression profile obtained in this study will help to understand the gene regulation during koji-making process to optimize A. kawachii as industrial microorganism. Gene expression of Aspergillus kawachii in barley koji was measured at 25, 26.5, and 44 hours at two different temperature control. Three independent experiments were performed at each time (25, 26.5, or 44 hours) using different barley koji for each expreriment.
Project description:We created a multi-species microarray platform, containing probes to the whole genomes of seven different Saccharomyces species, with very dense coverage (one probe every ~500 bp) of the S. cerevisiae genome, including non-S288c regions, mitochondrial and 2 micron circle genomes, plus probes at fairly dense coverage (one probe every ~2,100 bp) for each of the genomes of six other Saccharomyces species: S. paradoxus, S. mikatae, S. kudriavzevii, S. bayanus, S. kluyveri and S. castellii. We performed array-Comparative Genomic Hybridization (aCGH) using this platform, examining 83 different Saccharomyces strains collected across a wide range of habitats; of these, 69 were widely used commercial S. cerevisiae wine strains, while the remaining 14 were from a wide range of other industrial and natural habitats. Thus, we were able to sample much of the pan-genome space of the Saccharomyces genus. We observed interspecific hybridization events, introgression events, and pervasive copy number variation (CNV) in all but a few of the strains. These CNVs were distributed throughout the strains such that they did not produce any clear phylogeny, suggesting extensive mating in both industrial and wild strains. To validate our results and to determine whether apparently similar introgressions and CNVs were identical by descent or recurrent, we also performed whole genome sequencing on nine of these strains. These data may help pinpoint genomic regions involved in adaptation to different industrial milieus, as well as shed light on the course of domestication of S. cerevisiae.
Project description:The selection of bioengineering platform strains and engineering strategies to improve the stress resistance of Saccharomyces cerevisiae remains a pressing need in bio-based chemical production. Thus, a systematic effort to exploit the genotypic and phenotypic diversity to boost yeast’s industrial value is still urgently needed. Here, we analyzed 5400 growth curves obtained from 36 S. cerevisiae strains and comprehensively profiled their resistances against 13 industrially relevant stresses. We observed that bioethanol and brewing strains exhibit higher resistance against acidic conditions, however, plant isolates tend to have wider range of resistance, which may be associated with their metabolome and fluxome signatures in TCA cycle and fatty acid metabolism. By deep genomic sequencing we found that industrial strains have more genomic duplications especially affecting transcription factors, presenting disparate evolutionary paths in comparison to the environmental strains which have more InDels, gene deletions and strain-specific genes. Genome-wide association studies coupled with protein-protein interaction networks uncovered novel genetic determinants of stress resistances. These resistance-related engineering targets and strain rankings provide a valuable source for engineering significantly improved industrial platform strains.</br></br> This metabolomic study of 36 yeast strains measured intra- and extracellular metabolome under standard glucose medium, profiled by GS-MS. This is part of a multi-omic study on yeast strain collection.
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: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: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:Comparative genome-wide gene expression analysis between two industrial wine yeast hybrid strains belonging to the species S. cerevisiae x S. Kudriavzevii, in natural must fermentations.