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Toshihiro Kumamaru Last modified date:2021.05.11

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1)Genetic regulation of the biosynthesis, intracellular traffic, and accumulation of rice storage protein
2)Construction of rice mutant pool by National Bioresources Project (NBRP)
3)Collection, evaluation and preservation of rice genetic resources .
Academic Degree
Dr. of Agriculture
Country of degree conferring institution (Overseas)
Field of Specialization
Plant Genetics, Plant Physiology
ORCID(Open Researcher and Contributor ID)
Total Priod of education and research career in the foreign country
Research Interests
  • The production of the variety for rice oil
    keyword : giant embryo, rice oil
  • Genetic regulation of the synthesis, intracellular transportation and accumulation of rice storage proteins
    keyword : Prolamin, Glutelin, Endoplasmic reticulum, Golgi apparatus, Protein storage vacuole, Protein body, Protein Trafic
    1996.04~2020.03Rice seed storage proteins mainly compose of prolamin and glutelin. Both storage proteins mRNA are sorted to each subdomain of the ER (Hamada, et al, 2003), and both proteins are synthesized on each ER membrane and translocated into the ER lumen. They are stored in morphologically distinct protein body (PB; Tanaka et al., 1980; Krishnan et al., 1986; Yamagata and Tanaka, 1986). Prolamins are stored as intracisternal inclusion granules within the ER lumen (PB-I), whereas glutelins are packaged in a protein storage vacuolar compartment (PSV), same as globulins in dicot (PB-II; Tanaka et al., 1980; Krishnan et al., 1986). The two types of storage compartment in a cell is characteristic in rice. But, the genetic mechanism in the cellular process of the accumulation into protein bodies of both proteins has not been known well. The goal of the rearch is to clear the genetic mechanism of the accumulation of storage proteins into protein bodies..
  • Construction of rice mutation pool in National Bioresources Projest (NBRP)
    keyword : Rice, Mutation, Gene Function, N-methyl-N-nitrosourea, TILLING
  • Research on preservation and property evaluation in rice germplasm
    keyword : Genetic resource, Evaluation of trait, Native vriety, Database
Academic Activities
1. Kumamaru T., M. Ogawa, H Satoh, T. W. Okita, Protein body biogenesis in cereal endosperms. In Endosperm - Development and Molecular Biology, O.D. Olsen, ed. Plant Cell Monographs, Springer, In Endosperm ミ Development and Molecular Biology, O.A. Olsen, ed. Plant Cell Monographs 8, 141-158, 2007.10.
1. Elakhdar A., T. Ushijima, M. Fukuda, N. Yamashiro, Y. Kawagoe, T. Kumamaru., Eukaryotic peptide chain release factor 1 participates in translation termination of specific cysteine-poor prolamines in rice endosperm, Plant Science, org/10.1016/j.plantsci.2018.12.006, 281, 223-231, 2019.04.
2. M. Fukuda, Y. Kawagoe, T. Murakami, H. Washida, A. Sugino, A. Nagamine, T. W. Okita, M. Ogawa, T. Kumamaru, The Dual Roles of the Golgi Transport 1 (GOT1B): RNA Localization to the Cortical Endoplasmic Reticulum and the Export of Proglutelin and α-Globulin from the Cortical-ER to the Golgi., Plant and Cell Physiology, 10.1093/pcp/pcw154, 57, 11, 2380-2391, 2016.11.
3. Elakhdar, A., El-Sattar, M. A., Amer, K., Rady, A., Kumamaru T., Population structure and marker-trait association of salt tolerance in barley (Hordeum vulgare L.), Comptes rendus biologies, 10.1016/j.crvi.2016.06.006, 339, 11, 454-461, 2016.11.
4. Elakhdar Ammar, Ahmed, M. AbdEl-sattar, Khairy, A, Kumamaru T., Genetic diversity and association analysis among Egyptian barley (Hordeum vulgare L.) genotypes with different adaptations to saline conditions analyzed by SSR markers, Australian Journal of Crop Science, 10.21475/ajcs.2016.10.05.p7331, 10, 637-645, 2016.06.
5. Wen L., Fukuda M., Sunada M., Iahino S., Ishino Y., Okita T. W., Ogawa M., Ueda T., Kumamaru T., Guanine nucleotide exchange factor 2 for Rab5 proteins coordinated with GLUP6/GEF regulates the intracellular transport of the proglutelin from the Golgi apparatus to the protein storage vacuole in rice endosperm, Jouranl of Experimental Botany, 10.1093/jxb/erv325, 66 (20), 6137-6147, 2015.10.
6. Hoai T. T. T., Suu T. D., H. Satoh, T. Kumamaru, Diversity of glutelin acidic subunit polypeptides in rice cultivars collected from Northern Vietnam, Plant Breeding, 10.1111/pbr.12159, 133, 3, 341-347, 2014.06.
7. Hoai, T. T. T., M. Hiroaki, Y. Toyosawa, Suu T. D., H. Satoh, T. Kumamaru, Influence of single-nucleotide polymorphisms in the gene encoding granule-bound starch synthase I on amylose content in Vietnamese rice cultivars, Breeding Science, 10.1270/jsbbs.64.142, 64, 2, 142-148, 2014.06.
8. Fukuda M., Wen L., Satoh-Cruz M., Kawagoe Y., Nagamura Y., Okita T. W., Washida H., Sugino A., S. Iahino, Y. Ishino, Ogawa M., Sunada M., Ueda T., Kumamaru T., A guanine nucleotide exchange factor for Rab5 proteins is essential for intracellular transport of the proglutelin from the Golgi apparatus to the protein storage vacuole in rice endosperm, Plant Physiology, 10.1073/pnas.1216151110, 162, 2, 663-672, 2013.06.
9. Fukuda M., M. Satoh-Cruz, L. Wen, A. J. Crofts, A. Sugino, H. Washida, T. W. Okita, M. Ogawa, Y. Kawagoe, M. Maeshima, T. Kumamaru., The small GTPase Rab5a is essential for intracellular transport of proglutelin from Golgi apparatus to the protein storage vacuole and endosomal membrane organization in developing rice endosperm., Plant Physiology, 10.1104/pp.111.180505, 157, 2, 632-644, 2011.10.
10. Ushijima, T., H. Matsusaka, H. Jikuya, M. Ogawa, H. Satoh, T. Kumamaru, Genetic analysis of cysteine-poor prolamin polypeptides reduced in the endosperm of the rice esp1 mutant, Plant Science, 10.1016/j.plantsci.2011.04.011, 181, 125-131, 2011.08.
11. Ai Nagamine, Hiroaki Matsusaka, Tomokazu Ushijima, Yasushi Kawagoe, Masahiro Ogawa, Thomas W. Okita, Toshihiro Kumamaru, A Role for the Cysteine-Rich 10 kDa Prolamin in Protein Body I Formation in Rice, PLANT AND CELL PHYSIOLOGY, 10.1093/pcp/pcr053, 52, 6, 1003-1016, 2011.06, The rice prolamins consist of cysteine-rich 10 kDa (CysR10), 14 kDa (CysR14) and 16 kDa (CysR16) molecular species and a cysteine-poor 13 kDa (CysP13) polypeptide. These storage proteins form protein bodies (PBs) composed of single spherical intracisternal inclusions assembled within the lumen of the rough endoplasmic reticulum. Immunofluorescence and immunoelectron microscopy demonstrated that CysR10 and CysP13 were asymmetrically distributed within the PBs, with the former concentrated at the electron-dense center core region and the latter distributed mainly to the electron-lucent peripheral region. These results together with temporal expression data showed that the formation of prolamin-containing PB-I in the wild-type endosperm was initiated by the accumulation of CysR10 to form the center core. In mutants deficient for cysteine-rich prolamins, the typical PB-I structures containing the electron-dense center core were not observed, and instead were replaced by irregularly shaped, electron-lucent, hypertrophied PBs. Similar, deformed PBs were observed in a CysR10 RNA interference plant line. These results suggest that CysR10, through its formation of the central core and its possible interaction with other cysteine-rich prolamins, is required for tight packaging of the proteins into a compact spherical structure..
12. Hikaru Satoh, Hiroaki Matsusaka, Toshihiro Kumamaru, Use of N-methyl-N-nitrosourea treatment of fertilized egg cells for saturation mutagenesis of rice, BREEDING SCIENCE, 10.1270/jsbbs.60.475, 60, 5, 475-485, 2010.12, The efficiency of N-methyl-N-nitrosourea (MNU) treatment of fertilized egg cells at the single-cell stage in rice (Oryza saliva L.) was about twice that of dry seeds. The proportion of recessive iso-chlorophyll mutants in the segregating progeny of M-1 plants decreased remarkably with treatment at later stages of embryonic development, perhaps because of the presence of diplontic selection and chimera formation when older, multicellular embryos were mutagenized. Panicle sterility of the M-1 plants showed a linear relationship with the frequency of chlorophyll mutations in the progeny. The mutagenicity of N-ethyl-N-nitrosourea was similar to that of MNU, but N-methyl-N`-nitro-N-nitrosoguanidine and N-ethyl-N`-nitro-N-nitrosoguanidine were less effective. Several thousand rice mutants affecting endosperm, culm length, heading date, and chlorophyll were obtained by MNU mutagenesis. The frequency of certain types of endosperm mutants seemed to differ according to the precise timing of treatment. The mutation rate was calculated as 7.4 x 10(-6) per nucleotide, and the mutations were evenly distributed over the gene regions examined. These results indicate that our rice mutant library, generated by MNU mutagenesis, is a promising resource for identifying mutations in any rice gene..
13. Yuka Ueda, Mio Satoh-Cruz, Hiroaki Matsusaka, Yoko Takemoto-Kuno, Masako Fukuda, Thomas W. Okita, Masahiro Ogawa, Hikaru Satoh, Toshihiro Kumamaru, Gene-gene interactions between mutants that accumulate abnormally high amounts of proglutelin in rice seed, BREEDING SCIENCE, 10.1270/jsbbs.60.568, 60, 5, 568-574, 2010.12, We had previously identified eight mutants, esp2 and g(G)lups1 to 7, which accumulated abnormally high amounts of proglutelin, the major storage protein in rice seeds. Analysis of their seed proteins by SDS-PAGE, their levels of the luminal chaperone BiP and gene-gene interactions indicated that these mutants fell into four classes. The most epistatic class consisted of esp2, which encodes a defective protein disulfide isomerase (PDI). A second class consisting of Glup1, glup2 and glup7 was hypostatic to esp2, and showed abnormally high levels of BiP, suggesting that maturation and export of proglutelins from the ER are inhibited in this class of mutants. The third class containing glup4, Glup5 and glup6 mutations was hypostatic to esp2, Glup1, glup2 and glup7. Since the glup4 allele encodes the small GTPase Rab5a, which participates in the trafficking of proglutelin from Golgi apparatus to the protein storage vacuole (PSV), this third class of mutants is likely affected in this process. Lastly, glup3, which encodes a vacuolar processing enzyme, which proteolytically processes proglutelin into acidic and basic subunits within the PSV, was hypostatic to the other mutants. Overall, these gene relationships are consistent with the sequential intracellular transport and processing of proglutelin and provide novel insights on the trafficking of proglutelin to the PSV..
14. Mio Satoh-Cruz, Andrew J. Crofts, Yoko Takemoto-Kuno, Aya Sugino, Haruhiko Washida, Naoko Crofts, Thomas W. Okita, Masahiro Ogawa, Hikaru Satoh, Toshihiro Kumamaru, Protein Disulfide Isomerase Like 1-1 Participates in the Maturation of Proglutelin Within the Endoplasmic Reticulum in Rice Endosperm, PLANT AND CELL PHYSIOLOGY, 10.1093/pcp/pcq098, 51, 9, 1581-1593, 2010.09, The rice esp2 mutation was previously characterized by the abnormal accumulation of elevated levels of proglutelin and the absence of an endosperm-specific protein disulfide isomerase like (PDIL1-1). Here we show that Esp2 is the structural gene for PDIL1-1 and that this lumenal chaperone is asymmetrically distributed within the cortical endoplasmic reticulum (ER) and largely restricted to the cisternal ER. Temporal studies indicate that PDIL1-1 is essential for the maturation of proglutelin only when its rate of synthesis significantly exceeds its export from the ER, a condition resulting in its build up in the ER lumen and the induction of ER quality control processes which lower glutelin levels as well as those of the other storage proteins. As proglutelin is initially synthesized on the cisternal ER, its deposition within prolamine protein bodies in esp2 suggests that PDIL1-1 helps retain proglutelin in the cisternal ER lumen until it attains competence for ER export and, thereby, indirectly preventing heterotypic interactions with prolamine polypeptides..
15. Satoh-Cruz M., M. Fukuda, M. Ogawa, H. Satoh, and T. Kumamaru, Glup4 gene encodes small GTPase, Rab5a in rice, Rice Genetics Newsletter, 25, 48-49, 2010.05.
16. Toshihiro Kumamaru, Yuji Uemura, Yoshimi Inoue, Yoko Takemoto, Sadar Uddin Siddiqui, Masahiro Ogawa, Ikuko Hara-Nishimura, Hikaru Satoh, Vacuolar Processing Enzyme plays an Essential Role in the Crystalline Structure of Glutelin in Rice Seed, PLANT AND CELL PHYSIOLOGY, 10.1093/pcp/pcp165, 51, 1, 38-46, 2010.01, To identify the function of genes that regulate the processing of proglutelin, we performed an analysis of glup3 mutants, which accumulates excess amounts of proglutelin and lack the vacuolar processing enzyme (VPE). VPE activity in developing seeds from glup3 lines was reduced remarkably compared with the wild type. DNA sequencing of the VPE gene in glup3 mutants revealed either amino acid substitutions or the appearance of a stop codon within the coding region. Microscopic observations showed that -globulin and proglutelin were distributed homogeneously within glup3 protein storage vacuoles (PSVs), and that glup3 PSVs lacked the crystalline lattice structure typical of wild-type PSVs. This suggests that the processing of proglutelin by VPE in rice is essential for proper PSV structure and compartmentalization of storage proteins. Growth retardation in glup3 seedlings was also observed, indicating that the processing of proglutelin influences early seedling development. These findings indicate that storage of glutelin in its mature form as a crystalline structure in PSVs is required for the rapid use of glutelin as a source of amino acids during early seedling development. In conclusion, VPE plays an important role in the formation of protein crystalline structures in PSVs..
17. Jahan Md. S., Y. Uemura, T. Kumamaru, A. Hamid and H. Satoh., Genetic variation of glutelin acidic subunit polypeptides in Bangladesh rice genetic resources., Genetic Resources and Crop Evolution, 10.1007/s10722-003-6023-7, 52, 8, 977-987, 2005.01.
18. T. Kumamaru, Y. Uemura, Y. Takemoto, M. Ogawa and H. Satoh, High-resolution mapping of glup3 gene accumulating high amount of glutelin precursor, Rice Genetics Newsletter, 19, 62-63, 2002.12.
19. Ushijima, T., H. Satoh and T. Kumamaru., Mapping of esp1 gene for cystein-poor (CysP) prolamin decreased mutant in rice., Rice Genetics Newsletter, 19, 64-65, 2002.12.
20. Y Takemoto, SJ Coughlan, TW Okita, H Satoh, M Ogawa, T Kumamaru, The rice mutant esp2 greatly accumulates the glutelin precursor and deletes the protein disulfide isomerase, PLANT PHYSIOLOGY, 10.1104/pp.010624, 128, 4, 1212-1222, 2002.04, Rice (Oryza sativa) accumulates prolamins and glutelins as storage proteins. The latter storage protein is synthesized on the endoplasmic reticulum (ER) as a 57-kD proglutelin precursor, which is then processed into acidic and basic subunits in the protein storage vacuole. Three esp2 mutants CM1787, EM44, and EM747, contain larger amounts of the 57-kD polypeptide and corresponding lower levels of acidic and basic glutelin subunits than normal. Electron microscopic observation revealed that esp2 contained normal-appearing glutelin-containing protein bodies (PB-II), but lacked the normal prolamin-containing PB (PB-I). Instead, numerous small ER-derived PBs of uniform size (0.5 mum in diameter) and low electron density were readily observed. Immunoblot analysis of purified subcellular fractions and immunocytochemistry at the electron microscopy level showed that these new PBs contained the 57-kD proglutelin precursor and prolamin polypeptides. The 57-kD proglutelin was extracted with 1% (v/v) lactic acid solution only after removal of cysteine-rich prolamin polypeptides, suggesting that these proteins form glutelin-prolamin aggregates via interchain disulfide bonds within the ER lumen. The endosperm of esp2 mutants contains the lumenal chaperones, binding protein and calnexin, but lacks protein disulfide isomerase (PDI) at the protein and RNA levels. The transcript of PDI was expressed in the seed only during the early stage of seed development in the wild type. These results suggest that PDI plays an essential role in the segregation of proglutelin and prolamin polypeptides within the ER lumen..
21. Kumamaru, T., H. Sato and H. Satoh, High-lysine mutants of rice, Oryza sativa L., Plant Breeding, 116, 3, 245-249, 1997.08.
22. A. Bhowmik, T. Omura, Toshihiro Kumamaru, Screening of Rice Varieties for Endosperm Storage Proteins, Plant Breeding, 10.1111/j.1439-0523.1990.tb00461.x, 105, 2, 101-105, 1990.05.
23. Toshihiro Kumamaru, Hikaru Satoh, Takeshi Omura, Masahiro Ogawa, Mutants for rice storage proteins. IV. maternally inherited mutants for storage proteins of protein bodies in starchy endosperm, Heredity, 10.1038/hdy.1990.2, 64, 1, 9-15, 1990.01.
24. M. Ogawa, Toshihiro Kumamaru, H. Satoh, T. Omura, T. Park, K. Shintaku, K. Baba, Mutants for rice storage proteins - 2. Isolation and characterization of protein bodies from rice mutants, Theoretical And Applied Genetics, 10.1007/BF00265288, 78, 3, 305-310, 1989.09.
25. Toshihiro Kumamaru, H. Satoh, N. Iwata, T. Omura, M. Ogawa, K. Tanaka, Mutants for rice storage proteins - 1. Screening of mutants for rice storage proteins of protein bodies in the starchy endosperm, Theoretical And Applied Genetics, 10.1007/BF00288825, 76, 1, 11-16, 1988.07.
26. Masahiro Ogawa, Toshihiro Kumamaru, Hikaru Satoh, Nobuo Iwata, Takeshi Omura, Zenzaburo Kasai, Kunisuke Tanaka, Purification of protein body-I of rice seed and its polypeptide composition, Plant and Cell Physiology, 28, 8, 1517-1527, 1987.12.
27. Toshihiro Kumamaru, Nobuo Iwata, Takeshi Omura, Hikaru Satoh, Masahiro Ogawa, Mutants for rice storage proteins. III. Genetic analysis of mutants for storage proteins of protein bodies in the starchy endosperm, Genes and Genetic Systems, 10.1266/jjg.62.333, 62, 4, 333-339, 1987.01.
1. Tran Hong Quan, Hiroaki Matsusaka, Tomokazu Ushijima,Takahiko Kubo, Toshirhiro Kumamaru, Identification of genomic region harboring Endosperm Storage Protein (ESP) 3 gene regulating the Cysteine-rich prolamine by MutMap, 日本育種学会第14回九州育種談話会, 2019.11.
2. Saw Myat Nwe,Masako Fukuda,Toshihiro Kumamaru, The role of the Protein Disulfide Isomerase Like (PDIL) 2-3 in the accumulation of the storage proteins in rice endosperm, 日本育種学会第134回講演会, 2018.09.
3. Ammar Elakhdar, Tomokazu Ushijima, Masako Fukuda, Noriko Yamashiro, Yasushi Kawagoe, Toshihiro Kumamaru, The recognition assay of termination codon by ESP1/ eukaryote releases factor-1 (eRF1) in rice, International Plant & Animal Genome XXVI, 2018.01.
4. Ammar Elakhdar, Tomokazu Ushijima, Masako Fukuda, Noriko Yamashiro, Yasushi Kawagoe, Toshihiro Kumamaru, The recognition assay of termination codon by ESP1/ eukaryotic releases factor-1 (eRF1) in rice, 九州育種談話会, 2017.12.
5. Sobhy A., Fukuda M., and Kumamaru T., Guanine nucleotide exchange factor2 (GEF2) for Rab5 proteins is essential for intracellular transport of the proglutelin from the Golgi apparatus to the protein storage vacuole in rice endosperm., 九州育種談話会, 2017.12.
6. Ammar Elakhda, Tomokazu Ushijima, Masako Fukuda, Noriko Yamashiro, Yasushi Kawagoe, Toshihiro Kumamaru, Function of ESP1/eRF1 in the translation of prolamin polypeptides in rice endosperm, 日本育種学会, 2018.03.
7. Vacuolar processing enzyme plays an essential role in the formation of the glutelin crystalline structure in rice seed.
8. Seliction of mutant for Tudor-SN in rice.
9. The small GTPase Rab5a is essential for intracellular transport of glutelin precursor from Golgi apparatus and endosomal membrane organization in developing rice endosperm .
10. Rice genetic resources by MNU mutagenesis.
11. Vacuolar processing enzyme plays an essential role in the formation of the glutelin crystalline structure in rice seed.
12. The role of cysteine-rich prolamines for the formation of prolamine protein body .
13. The small GTPase Rab5a is essential for intracellular transport of glutelin precursor from Golgi apparatus and endosomal membrane organization in developing rice endosperm .
14. Esp1 gene, regulatory factor in rice cysteine-poor prolamin, encode a peptide release factor (eucaryotic Release Factor 1, eRF1).
Membership in Academic Society
  • American Society of Plant Biologist
Educational Activities
Graduated School classes
Plant Genetic Engineering

Under Graduated School classe
Basic Genetics