Effect of temperature on gene expression profile of Aspergillus kawachii during a barley koji-making process

ABSTRACT: 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 40°C and then lowering to 30°C. The cultivation at 40°C and the following at lower temperature of 30°C 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 40°C from 30°C. 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 40°C 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.

ORGANISM(S): Aspergillus luchuensis Aspergillus luchuensis IFO 4308

PROVIDER: GSE58454 | GEO | 2014/06/14

SECONDARY ACCESSION(S): PRJNA252669

REPOSITORIES: GEO