Mycotoxin production and genetic analysis of Aspergillus niger and related species including the Kuro-Koji mold

Hashimoto, Ruiko; Asano, Katsuyoshi; TOKASHIKI, Tadaaki; Onji, Yoshiki; Hirose-Yasumoto, Mina; TOYOSATO, Tetsuya; YOSHINO, Atsushi; IKEHATA, Mami; Liu, Ying; Kumeda, Yuko; Yokoyama, Koji; Takahashi, Hitomi

doi:10.2520/myco.63.179

Cited by 6 publications

(4 citation statements)

References 17 publications

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“…Previous genome analysis of A. kawachii IFO 4308 revealed that an approximately 21-kb genomic region that includes the polyketide (12). A. kawachii also does not produce fumonisin (7), which is consistent with the finding that A. kawachii IFO 4308 lacks orthologs of nearly all fum genes involved in fumonisin biogenesis in A. niger (see Table S2 in the supplemental material) (19,21).…”

Section: Genome Comparisonsupporting

confidence: 76%

“…kawachii has similar genomic and physiological features as Aspergillus niger, which is industrially used for the production of protein and citric acid. However, A. kawachii is clearly distinct from most A. niger strains with respect to the production of mycotoxins (5)(6)(7). Although several A. niger strains produce the mycotoxins fumonisin and ochratoxin, A. kawachii does not produce these mycotoxins.…”

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confidence: 83%

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Transcriptomic Analysis of Temperature Responses of Aspergillus kawachii during Barley Koji Production

Futagami

Mori

Wada³

et al. 2015

Appl Environ Microbiol

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cThe koji mold Aspergillus kawachii is used for making the Japanese distilled spirit shochu. During shochu production, A. kawachii is grown in solid-state culture (koji) on steamed grains, such as rice or barley, to convert the grain starch to glucose and produce citric acid. During this process, the cultivation temperature of A. kawachii is gradually increased to 40°C and is then lowered to 30°C. This temperature modulation is important for stimulating amylase activity and the accumulation of citric acid. However, the effects of temperature on A. kawachii at the gene expression level have not been elucidated. In this study, we investigated the effect of solid-state cultivation temperature on gene expression for A. kawachii grown on barley. The results of DNA microarray and gene ontology analyses showed that the expression of genes involved in the glycerol, trehalose, and pentose phosphate metabolic pathways, which function downstream of glycolysis, was downregulated by shifting the cultivation temperature from 40 to 30°C. In addition, significantly reduced expression of genes related to heat shock responses and increased expression of genes related with amino acid transport were also observed. These results suggest that solid-state cultivation at 40°C is stressful for A. kawachii and that heat adaptation leads to reduced citric acid accumulation through activation of pathways branching from glycolysis. The gene expression profile of A. kawachii elucidated in this study is expected to contribute to the understanding of gene regulation during koji production and optimization of the industrially desirable characteristics of A. kawachii.

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Section: Genome Comparisonsupporting

confidence: 76%

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confidence: 83%

Transcriptomic Analysis of Temperature Responses of Aspergillus kawachii during Barley Koji Production

Futagami

Mori

Wada³

et al. 2015

Appl Environ Microbiol

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“…In addition, enriched terms included numerous secondary metabolic related terms, such as the secondary metabolic process (GO:0019748) and mycotoxin biosynthetic process (GO:0043386). It should be noted that A. kawachii does not produce mycotoxins, such as ochratoxin A and fumonisin B, and is considered safe for use in the food and beverage industry (22, 23).…”

Section: Resultsmentioning

confidence: 99%

Overexpression of the RNA-binding protein NrdA affects global gene expression and secondary metabolism inAspergillusspecies

Kadooka

Izumitsu

Asai

et al. 2021

Preprint

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RNA-binding protein Nrd1 plays a role in RNA polymerase II transcription termination. In this study, we showed that the orthologous NrdA is important in global mRNA expression and secondary metabolism in Aspergillus species. We constructed an nrdA conditional expression strain using the Tet-On system in Aspergillus luchuenesis mut. kawachii. Downregulation of nrdA caused a severe growth defect, indicating that NrdA is essential for the proliferation of A. kawachii. Parallel RNA-sequencing and RNA immunoprecipitation-sequencing analysis identified potential NrdA-interacting transcripts, corresponding to 32% of the predicted protein coding genes of A. kawachii. Subsequent gene ontology analysis suggested that overexpression of NrdA affects the production of secondary metabolites. To clarify this, we constructed NrdA-overexpressing strains of Aspergillus nidulans, Aspergillus fumigatus, and Aspergillus oryzae. Overexpression of NrdA reduced the production of sterigmatocystin and penicillin in A. nidulans, as well as that of helvolic acid and pyripyropene A in A. fumigatus. Moreover, it increased the production of kojic acid and reduced production of penicillin in A. oryzae. These effects were accompanied by almost consistent transcriptional changes in the relevant genes. Collectively, these results suggest that NrdA is the essential RNA-binding protein, which plays a significant role in global gene expression and secondary metabolism in Aspergillus species.

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“…However, in the Okinawa region, several fungal strains used in brewing since antiquity form a group that is clearly distinct even among the other Aspergillus section Nigri strains. Moreover, these strains are non-fumonisin producers 24) . It may be that domestication of fumonisin producers led to artificial selection of strains for brewing with a low potential for fumonisin production.…”

Section: Discussionmentioning

confidence: 99%

Fumonisin-production by <i>Aspergillus</i> section <i>Nigri</i> isolates from Japanese Foods and Environments

Onami¹,

Watanabe

Yoshinari

et al. 2018

Food Safety

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Fumonisins are well known as mycotoxins produced by various Fusarium species. Recently Aspergillus niger has been reported to be a fumonisin B 2 (FB 2 ) producer. Aspergillus niger is a member of Aspergillus section Nigri. Members of this section are common food contaminants and are also distributed widely in the environment. This study aimed to determine 1) optimum culture conditions of A. niger for fumonisin production including growth medium, temperature and incubation period and 2) fumonisin production among isolates of Aspergillus section Nigri and closely related species isolated from Japanese food and environmental samples. Growth on Czapek yeast extract broth +5% NaCl (CYBS) at 28°C for 7 days resulted in the highest levels of FB 2 production as determined by quantitative LC-MS/MS of culture extracts. Sixty-two isolates were collected from various foods in domestic markets as well as from soil and air. The isolates principally separated into two groups; A. niger and A. luchuensis/A. piperis/A. tubingensis, following molecular phylogenetic analysis. ELISA using the tip culture method was shown to be suitable for screening of the fumonisin-producing strains. Phylogenic analysis of Aspergillus section Nigri isolates from food and environmental samples indicated that fumonisin producing strains could be grouped into the A. niger clade. Nineteen of 35 (54%) isolates classified as A. niger were FB 2 producers. The current study suggests that FB 2 -producing A. niger are distributed throughout several regions of Japan.

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Mycotoxin production and genetic analysis of Aspergillus niger and related species including the Kuro-Koji mold

Cited by 6 publications

References 17 publications

Transcriptomic Analysis of Temperature Responses of Aspergillus kawachii during Barley Koji Production

Transcriptomic Analysis of Temperature Responses of Aspergillus kawachii during Barley Koji Production

Overexpression of the RNA-binding protein NrdA affects global gene expression and secondary metabolism inAspergillusspecies

Fumonisin-production by <i>Aspergillus</i> section <i>Nigri</i> isolates from Japanese Foods and Environments

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