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Naoki Hirotsu

    Department of Biological Resources　Professor
    Course of Life Sciences　Professor
Last Updated :2024/04/06

Researcher Information

Degree

  • Doctor of Agriculture（2005/03 Tohoku University）

URL

Research funding number

  • 40584389

ORCID ID

J-Global ID

Research Interests

  • Rice   Grain yield   phytic acid   QTL   Photosynthesis   Environmental response   Amphibious plants   水草   

Research Areas

  • Environmental science/Agricultural science / Plant genetics and breeding
  • Environmental science/Agricultural science / Crop production science
  • Life sciences / Plants: molecular biology and physiology

Academic & Professional Experience

  • 2018/04 - Today  Toyo UniversityFaculty of Life SciencesProfessor
  • 2019/10 - 2021/08  National Institute of Fundamental Studies, Sri Lanka,Adjunct Professor
  • 2016/04 - 2019/03  University of Southern Queensland,Centre for Crop Health,Adjunct Associate Professor
  • 2010/04 - 2018/03  Toyo UniversityFaculty of Life Sciences, Department of Life Sciences
  • 2015/04 - 2016/03  University of Southern Queensland,Center for Crop Health,Visiting Academic
  • 2005 - 2010  National Institute of Agrobiological Sciences

Education

  •        - 2005  Tohoku University  農学研究科  応用生命科学専攻
  •        - 2005  Tohoku University  Graduate School, Division of Agriculture
  •        - 2000  Tohoku University  Faculty of Agriculture  生物化学科
  •        - 2000  Tohoku University  Faculty of Agriculture

Association Memberships

  • THE BOTANICAL SOCIETY OF JAPAN   THE JAPANESE SOCIETY OF PHOTOSYNTHESIS RESEARCH   日本作物学会   日本植物生理学会   

Published Papers

Books etc

  • Genetic Engineering and Genome Editing for Zinc Biofortification of Rice
    Ishara Perera; Naoki Hirotsu (ContributorChapter10: Improving bioavailability of zinc in rice grains by reducing antinutrients through genetic engineering)Academic Press, Elsevier 2023 9780323854061
  • Food Security and Climate Change
    Saman Seneweera; Kiruba Shankari Arun-Chinnappa; Naoki Hirotsu (ContributorChapter 06: Scope, Options and Approaches to Climate Change)Wiley-Blackwell 2019/01 9781119180647 536

Conference Activities & Talks

MISC

Industrial Property Rights

Awards & Honors

  • 2020/03 Japanese Society of Crop Science Research Award
     Genetic and physiological studies of rice yield and its related traits 
    受賞者: Ken Ishimaru;Takayuki Kashiwagi;Naoki Hirotsu
  • 2010/03 Japanese Society of Crop Science Best Paper Award
     JPN

Research Grants & Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2023/04 -2026/03 
    Author : 廣津 直樹; 加藤 悦子; 長谷川 輝明
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2020/04 -2023/03 
    Author : Hirotsu Naoki
     
    THOUSAND-GRAIN WEIGHT 6 (TGW6) increases grain weight in rice by genetic loss of function, antagonists that specifically inhibit TGW6 can be expected to increase grain weight. In this study, we obtained recombinant TGW6 and determined the protein structure of TGW6 by X-ray crystallography. Furthermore, we screened compounds that interact with TGW6 by thermal shift assay and 19F NMR competition experiments, and obtained several candidates of antagonist. Some of these compounds were suggested to bind to the active site of TGW6, these compounds can be expected as the effective candidate for TGW6 antagonists.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
    Date (from‐to) : 2016/04 -2019/03 
    Author : Hirotsu Naoki
     
    NIL(TGW6), near-isogenic line carrying Kasalath type (loss of function) chromosome around TGW6 gene in Koshihikari background were used in this study. NIL(TGW6) accumulated starch in lower leaf sheath compared with Koshihikari. The expression level of genes related starch synthesis were up-regulated and starch degradation were down-regulated in NIL(TGW6). Similarly, IAA inhibitor treated Koshihikari significantly increased starch contents in lower leaf sheath, and showed similar gene expression as NIL(TGW6). It is considered that IAA involves in starch degradation in the lower leaf sheath of rice. By field trial, NIL(TGW6) significantly increased perfect grain ratio than Koshihikari. The starch accumulated in NIL(TGW6) by the heading stage was translocated to panicle via culm by the Maturity stage. It is suggested that the higher supply capacity of carbohydrate could be kept demand of carbohydrates during the ripening stage and reduced the immature grains.
  • Ceylon Cinnamon Value Chain Development: Making global market space for value chain actors
    National Science Foundation of Sri Lanka：Cinnamon Research for Innovation
    Date (from‐to) : 2017 -2019 
    Author : D.A.M. De Silva
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2013 -2015 
    Author : Hirotsu Naoki
     
    I investigated the growth mechanism of rice by quantitative trait locus (QTL) analysis. Four QTLs associated with increased in plant growth rate were identified which were derived from ‘Kasalath’ alleles on chromosomes 1, 6, 8 and 12. This was achieved by evaluating the net dry weight gain between two developmental points. Physiological analysis revealed that the QTL on chromosome 1 (qEGR1) increased the relative growth rate (RGR) by enhancing the net assimilation rate (NAR). High RGR and NAR were facilitated by an increase in gene expression of OsSPS1 that encodes the rate-limiting enzyme in sucrose synthesis. In contrast, QTLs on chromosomes 6, 8 and 12 (qEGR6, qEGR8 and qEGR12) were associated with an increase in uptake of NH4+, the major nitrogen source for rice. These results suggest that growth mechanism is controlled by multiple traits but sucrose biosynthesis and NH4+ uptake play the key role in determining early growth rate of rice plant.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2011 -2013 
    Author : KASHIWADA Shosaku; TATSUTA Haruki; NAGASAKA Seiji; HIROTSU Naoki; SAKAMOTO Masaki; SHIMIZU Kazuya; TAKEI Hiroyuki; KATSUMATA Masakazu
     
    Minimum bactericidal concentration of silver nanocolloids (SNCs) to active sludge was 5 mg/L. Toxicities of SNCs to cyanobacteria and micro algae were comparatively high, in addition, nano-size dependent toxicity was observed. In case of SNCs exposure to aquatic plants, there was inhibition of roots growth because released Ag+ inhibited glutathione reductase and following increase of H2O2 in roots reduced catalase activity. There is no significant difference between SNCs and AgNO3 in acute mobility inhibition test of invertebrates. Main toxic factor in reproduction test of invertebrates was Ag+. In fish, it was observed that shortened body length, reduction of heart beating, ischemia and kyphosis were induced by SNCs exposure. SOD, CAT and GSH were significantly reduced, and apoptosis inhibition was observed. Moreover, intrinsic growth rate of fish was significantly decreased by SNCs exposure.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2010 -2011 
    Author : HIROTSU Naoki
     
    I tested the effects of free air CO_2 enrichment(FACE) on OsSPS1 gene expression and biomass production using chromosome segment substituted line which carries Kasalath allele OsSPS1 [CSSL(SPS)]. OsSPS1 gene expression levels and the dry weight of culm were increased in CSSL(SPS) under FACE condition.
  • Genetic Improvement of Koshihikari by Molecular Breeding
    Promotion of Basic Research Activities for Innovative Biosciences
    Date (from‐to) : 2005

Committee Membership

  • 2022/04 - Today   Plant Production Science, Editor
  • 2021/04 - Today   Frontiers in Plant Science (Plant Physiology section), Associate Editor
  • 2020/03 - Today   Plants, Editorial Board Members

Other link

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