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Invasive growth of Aspergillus oryzae in rice koji and increase of nuclear number
Norio Takeshita
Tsukuba Daigaku
Corresponding Author
ORCiD: https://orcid.org/0000-0003-2666-4991
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: ‘Rice koji’ is a solid culture of Aspergillus oryzae on steamed rice grains. Multiple parallel fermentation, wherein saccharification of rice by A. oryzae and alcohol fermentation by the budding yeast occur simultaneously, lead to the formation of a variety of ingredients of Japanese sake. In sake brewing, the degree of mycelial invasive growth into the steamed rice, called ‘haze-komi’, highly correlates with the digestibility and quality of rice koji, since the hyphae growing into the rice secrete amylases and digest starch of rice.
Results: In this study, we investigated mycelial distribution of GFP-tagged A. oryzae in rice koji made with different types of rice, such as sake rice and eating rice, with 50 or 90% polishing rate to remove abundant proteins and lipids near the surface. In addition, we compared transcriptomes of A. oryzae in the different types of rice koji. Finally, we found that A. oryzae increases the nuclear number and hyphal width in the course of 1-3 days cultivation.
Conclusions: Our imaging analyses indicate that A. oryzae hyphae grew more deeply into 50% polished rice than 90% polished rice. The increases of nuclear number may be a selectively acquired characteristic for the high secretory capacity during the breeding in long history.
Keywords
Aspergillus oryzae, koji, rice, nuclei, mitosis
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Posted 19 May, 2020
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Editorial decision: Minor revision
On 17 May, 2020
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On 06 May, 2020
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On 05 May, 2020
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Editorial decision: Minor revision
On 25 Mar, 2020
Review #2 received
Received 22 Mar, 2020
Reviewer #2 agreed
On 27 Feb, 2020
Review #1 received
Received 24 Feb, 2020
Reviewer #1 agreed
On 19 Feb, 2020
Reviewers invited
Invitations sent on 17 Feb, 2020
First submitted
On 28 Jan, 2020
Editor assigned
On 28 Jan, 2020
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On 27 Jan, 2020
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This preprint is under consideration at Fungal Biology and Biotechnology. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Invasive growth of Aspergillus oryzae in rice koji and increase of nuclear number
Norio Takeshita
Tsukuba Daigaku
Corresponding Author
ORCiD: https://orcid.org/0000-0003-2666-4991
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 2
Posted 19 May, 2020
No community comments so far
Editorial decision: Minor revision
On 17 May, 2020
Editor assigned
On 06 May, 2020
Submission checks complete
On 05 May, 2020
Editor invited
On 05 May, 2020
No comments provided
Editorial decision: Minor revision
On 25 Mar, 2020
Review #2 received
Received 22 Mar, 2020
Reviewer #2 agreed
On 27 Feb, 2020
Review #1 received
Received 24 Feb, 2020
Reviewer #1 agreed
On 19 Feb, 2020
Reviewers invited
Invitations sent on 17 Feb, 2020
First submitted
On 28 Jan, 2020
Editor assigned
On 28 Jan, 2020
Submission checks complete
On 27 Jan, 2020
Editor invited
On 27 Jan, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Biotechnology and Bioengineering
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: ‘Rice koji’ is a solid culture of Aspergillus oryzae on steamed rice grains. Multiple parallel fermentation, wherein saccharification of rice by A. oryzae and alcohol fermentation by the budding yeast occur simultaneously, lead to the formation of a variety of ingredients of Japanese sake. In sake brewing, the degree of mycelial invasive growth into the steamed rice, called ‘haze-komi’, highly correlates with the digestibility and quality of rice koji, since the hyphae growing into the rice secrete amylases and digest starch of rice.
Results: In this study, we investigated mycelial distribution of GFP-tagged A. oryzae in rice koji made with different types of rice, such as sake rice and eating rice, with 50 or 90% polishing rate to remove abundant proteins and lipids near the surface. In addition, we compared transcriptomes of A. oryzae in the different types of rice koji. Finally, we found that A. oryzae increases the nuclear number and hyphal width in the course of 1-3 days cultivation.
Conclusions: Our imaging analyses indicate that A. oryzae hyphae grew more deeply into 50% polished rice than 90% polished rice. The increases of nuclear number may be a selectively acquired characteristic for the high secretory capacity during the breeding in long history.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7