Dataset Information

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis.

ABSTRACT:

Background

Ashbya gossypii naturally overproduces riboflavin and has been utilized for industrial riboflavin production. To improve riboflavin production, various approaches have been developed. In this study, to investigate the change in metabolism of a riboflavin-overproducing mutant, namely, the W122032 strain (MT strain) that was isolated by disparity mutagenesis, genomic analysis was carried out.

Results

In the genomic analysis, 33 homozygous and 1377 heterozygous mutations in the coding sequences of the genome of MT strain were detected. Among these heterozygous mutations, the proportion of mutated reads in each gene was different, ranging from 21 to 75%. These results suggest that the MT strain may contain multiple nuclei containing different mutations. We tried to isolate haploid spores from the MT strain to prove its ploidy, but this strain did not sporulate under the conditions tested. Heterozygous mutations detected in genes which are important for sporulation likely contribute to the sporulation deficiency of the MT strain. Homozygous and heterozygous mutations were found in genes encoding enzymes involved in amino acid metabolism, the TCA cycle, purine and pyrimidine nucleotide metabolism and the DNA mismatch repair system. One homozygous mutation in AgILV2 gene encoding acetohydroxyacid synthase, which is also a flavoprotein in mitochondria, was found. Gene ontology (GO) enrichment analysis showed heterozygous mutations in all 22 DNA helicase genes and genes involved in oxidation-reduction process.

Conclusion

This study suggests that oxidative stress and the aging of cells were involved in the riboflavin over-production in A. gossypii riboflavin over-producing mutant and provides new insights into riboflavin production in A. gossypii and the usefulness of disparity mutagenesis for the creation of new types of mutants for metabolic engineering.

SUBMITTER: Kato T

PROVIDER: S-EPMC7181572 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Publications

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis.

Kato Tatsuya T Azegami Junya J Yokomori Ami A Dohra Hideo H El Enshasy Hesham A HA Park Enoch Y EY

BMC genomics 20200423 1

<h4>Background</h4>Ashbya gossypii naturally overproduces riboflavin and has been utilized for industrial riboflavin production. To improve riboflavin production, various approaches have been developed. In this study, to investigate the change in metabolism of a riboflavin-overproducing mutant, namely, the W122032 strain (MT strain) that was isolated by disparity mutagenesis, genomic analysis was carried out.<h4>Results</h4>In the genomic analysis, 33 homozygous and 1377 heterozygous mutations i ...[more]

PMID: 32326906

Similar Datasets

Project description:BackgroundThe fungus Ashbya gossypii is an important industrial producer of the vitamin riboflavin. Using this microbe, riboflavin is manufactured in a two-stage process based on a rich medium with vegetable oil, yeast extract and different precursors: an initial growth and a subsequent riboflavin production phase. So far, our knowledge on the intracellular metabolic fluxes of the fungus in this complex process is limited, but appears highly relevant to better understand and rationally engineer the underlying metabolism. To quantify intracellular fluxes of growing and riboflavin producing A. gossypii, studies with different 13C tracers were embedded into a framework of experimental design, isotopic labeling analysis by MS and NMR techniques, and model-based data processing. The studies included the use 13C of yeast extract, a key component used in the process.ResultsDuring growth, the TCA cycle was found highly active, whereas the cells exhibited a low flux through gluconeogenesis as well as pentose phosphate pathway. Yeast extract was the main carbon donor for anabolism, while vegetable oil selectively contributed to the proteinogenic amino acids glutamate, aspartate, and alanine. During the subsequent riboflavin biosynthetic phase, the carbon flux through the TCA cycle remained high. Regarding riboflavin formation, most of the vitamin's carbon originated from rapeseed oil (81 ± 1%), however extracellular glycine and yeast extract also contributed with 9 ± 0% and 8 ± 0%, respectively. In addition, advanced yeast extract-based building blocks such as guanine and GTP were directly incorporated into the vitamin.ConclusionIntracellular carbon fluxes for growth and riboflavin production on vegetable oil provide the first flux insight into a fungus on complex industrial medium. The knowledge gained therefrom is valuable for further strain and process improvement. Yeast extract, while being the main carbon source during growth, contributes valuable building blocks to the synthesis of vitamin B2. This highlights the importance of careful selection of the right yeast extract for a process based on its unique composition.

Dataset Information

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis.

Background

Results

Conclusion

Publications

Genomic analysis of a riboflavin-overproducing Ashbya gossypii mutant isolated by disparity mutagenesis.

Similar Datasets

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