論文 - 平野 智也
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Toshima Saki, Egashira Kodai, Mimura Makiko, Saeki Yuichi, Hirano Tomonari, Kunitake Hisato
Plant Molecular Biology Reporter 44 56 2026年2月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Springer Science and Business Media LLC
Widely distributed from East Asia to Australia, Rubus parvifolius is the only known wild Rubus species that naturally grows throughout the Japanese Archipelago, including small southern islands. R. parvifolius has been attracting attention as a genetic resource in Asia for breeding raspberries with enhanced tolerance to environmental stresses. Amami Oshima and Kakeroma, two of Japan’s Amami Islands, exhibit high plant diversity due to significant species endemism, reflecting the islands' isolated biogeographical history. This provides a rationale for focusing on Amami Oshima and Kakeroma Islands as a suitable system for studying wild Rubus species. In this study, we conducted ploidy assessments and analyzed Simple Sequence Repeat (SSR) markers in 24 accessions of R. parvifolius and other wild Rubus species (R. grayanus and R. croceacanthus) from those islands. Ploidy evaluation using flow cytometry and chromosome observation revealed that 11 of the 24 accessions (45.8%) were triploid. In addition, 52 SSR markers were employed, of which 20 were selected for analysis. Principal coordinate analysis (PCoA) using these SSR markers showed that diploid and triploid individuals did not form distinct clusters. Although this study was preliminary and based on a limited sample size, a relatively frequent occurrence of polyploid individuals was observed among the R. parvifolius accessions examined from Amami Oshima and Kakeroma. Our results provide baseline information on the occurrence of polyploid individuals in wild species in island systems.
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Narasako Yosuke, Setoguchi Yuno, Fukutome Haruka, Hirano Tomonari, Otani Motoyasu, Takeshita Minoru, Kunitake Hisato
Horticulturae 11 ( 12 ) 1439 2025年11月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：MDPI AG
Foot rot, a disease caused by the fungal plant pathogen Diaporthe destruens, has been a major problem throughout East Asia. In major sweet-potato-producing regions, developing sweet potato cultivars that are resistant to foot rot has become an urgent priority. The possibility of selecting resistant cultivars by using polyphenols in the stems as markers was recently suggested, but this selection method has not been tested in the crossbreeding of sweet potato cultivars. In this study, we crossed the sweet potato cultivars ‘Konaishin’ and ‘Tamaakane’ (each of which is resistant to foot rot), analyzed the polyphenols in the stems of the resulting hybrid lines, and evaluated the possibility of selecting resistant lines. As a result, KT No. 7 and KT No. 8 showed similar or lower total polyphenol contents (145.9 and 112.9 mg GAE 100 g−1 FW, respectively) compared to ‘Tamaakane’ (142.2 mg GAE 100 g−1 FW). The selected line, KT No. 7, exhibited the highest resistance among the hybrids when it was directly inoculated with the foot rot pathogen using stems as test material, showing a disease severity value of 1.8, which was substantially lower than that of ‘Tamaakane’ (50.0). These results suggest that stem polyphenol content has potential as a marker for identifying promising candidates with foot rot resistance, although its predictive value may vary depending on genetic and environmental factors. This approach may help improve the efficiency of foot rot resistance screening in sweet potato breeding programs.ms.
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Setoguchi Yuno, Fukutome Haruka, Narasako Yosuke, Hirano Tomonari, Otani Motoyasu, Takeshita Minoru, Kunitake Hisato
Journal of the American Society for Horticultural Science 150 ( 3 ) 159 - 167 2025年5月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：American Society for Horticultural Science
Foot rot (Diaporthe destruens) of sweetpotato generally infects the stem of the plant and then spreads throughout the plant. In Japan, foot rot is prevalent in the main area of sweetpotato production, and there is a pressing need for the development of resistant cultivars. It is generally believed that polyphenols are involved in defense against stress. However, little is known about the relationship between polyphenols and the susceptibility to foot rot in sweetpotato. We thus analyzed the polyphenol of the disease-free healthy stems and investigated their relationship between susceptibility to the disease to establish basic techniques for selecting cultivars resistant to foot rot. Polyphenol was analyzed by the Folin–Ciocalteu method and high-performance liquid chromatography. Resistance tests were conducted using the direct inoculation method. We observed a correlation between the total polyphenol content and the degree of foot rot disease severity. Surprisingly, cultivars with a low stem polyphenol content (‘Tamaakane’) had lower susceptibility to foot rot, whereas the cultivars with high stem polyphenol content (‘Kokei No. 14’) had higher susceptibility to foot rot. In particular, high positive correlations were shown with several polyphenols, including 3,4-dicaffeoylquinic acid and chlorogenic acid. Furthermore, the results of in vitro experiments also suggested that foot rot may metabolize trace amounts of chlorogenic acid. This discovery has potential applications in the selection of resistant cultivars, contributing to the streamlining of disease resistance tests in breeding programs. It could ultimately shorten the breeding period and help overcome foot rot disease in sweetpotato.
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Tomonari Hirano, Muneaki Murata, Yurie Watarikawa, Yoichiro Hoshino, Tomoko Abe, Hisato Kunitake
Plant Reproduction 37 ( 3 ) 355 - 363 2024年9月
担当区分：筆頭著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Plant Reproduction
Key message: In Cyrtanthus mackenii, development of embryo and endosperm were differentially affected by fertilization of male gametes with DNA damage and mutations. Abstract: Pollen irradiation with ionizing radiations has been applied in plant breeding and genetic research, and haploid plant induction has mainly been performed by male inactivation with high-dose irradiation. However, the fertilization process of irradiated male gametes and the early development of embryo and endosperm have not received much attention. Heavy-ion beams, a type of radiation, have been widely applied as effective mutagens for plants and show a high mutation rate even at low-dose irradiation. In this study, we analyzed the effects of male gametes of Cyrtanthus mackenii irradiated with a carbon-ion beam at low doses on fertilization. In immature seeds derived from the pollination of irradiated pollen grains, two types of embryo sacs were observed: embryo sac with a normally developed embryo and endosperm and embryo sac with an egg cell or an undivided zygote and an endosperm. Abnormalities in chromosome segregation, such as chromosomal bridges, were observed only in the endosperm nuclei, irrespective of the presence or absence of embryogenesis. Therefore, in Cyrtanthus, embryogenesis is strongly affected by DNA damage or mutations in male gametes. Moreover, various DNA contents were detected in the embryo and endosperm nuclei, and endoreduplication may have occurred in the endosperm nuclei. As carbon-ion irradiation causes chromosomal rearrangements even at low doses, pollen irradiation can be an interesting tool for studying double fertilization and mutation heritability.
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菅本 和寛, 平野 智也, 國武 久登
Plants 13 ( 13 ) 1864 2024年7月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：MDPI AG
The leaves and branches of rabbiteye blueberry are rich in proanthocyanidins, which are thought to have different physiological activities depending on their structure and degree of polymerization. In this study, we analyzed the constituents of the leaves and branches of rabbiteye blueberry to determine the seasonal variations in polyphenol and proanthocyanidin (PAC) contents as well as their mean degrees of polymerization (mDP). Total PAC content was determined using two methods: The p-dimethylaminocinnamaldehyde (DMACA) method, which measures monomeric PAC, showed an increase from spring to summer in both leaves and branches. On the other hand, using the butanol/HCl method, which measures only polymerized PAC, the PAC content of leaves increased from spring to summer but those of branches remained low throughout the year, showing no significant increase or decrease. Furthermore, analysis of the mDP of PAC showed increases from spring to summer in the leaves of ‘Kunisato 35 gou’. Although the highest value (8.0) was observed in October, values around 4 remained throughout the year in the branches. Since differences in polymerization degree affect absorption in the body and physiological properties such as antioxidant capacity, selecting the appropriate harvest time and plant organs for each purpose is expected to ensure the quality of processed blueberry foods.
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Makiko Shii, Yuki Kajiya, Muneaki Murata, Tomoko Abe, Hisato Kunitake, Tomonari Hirano
CYTOLOGIA 89 ( 2 ) 133 - 139 2024年6月
担当区分：最終著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌）
DOI： https://doi.org/10.1508/cytologia.89.133
その他リンク： https://www.jstage.jst.go.jp/article/cytologia/89/2/89_D-24-00011/_article/-char/en
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Changes in Carotenoids and Polyphenols during the Growth Stages of Orange-Fleshed Sweet Potato (Ipomoea batatas (L.) Lam.) 査読あり
Yuno Setoguchi, Yosuke Narasako, Tomonari Hirano, Motoyasu Otani, Hisato Kunitake
Horticulturae 10 ( 6 ) 629 2024年6月
掲載種別：研究論文（学術雑誌）
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Principles of amyloplast replication in the ovule integuments of Arabidopsis thaliana. 査読あり
Fujiwara MT, Yoshioka Y, Kazama Y, Hirano T, Niwa Y, Moriyama T, Sato N, Abe T, Yoshida S, Itoh RD
Plant physiology 196 ( 1 ) 137 - 152 2024年6月
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Kotaro Ishii , Yusuke Kazama, Tomonari Hirano, Jeffrey A. Fawcett, Muneo Sato, Masami Yokota Hirai, Fujiko Sakai, Yuki Shirakawa, Sumie Ohbu, Tomoko Abe
Frontiers in Plant Science 15 1352564 2024年4月
担当区分：筆頭著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Frontiers in Plant Science
Heavy-ion beam, a type of ionizing radiation, has been applied to plant breeding as a powerful mutagen and is a promising tool to induce large deletions and chromosomal rearrangements. The effectiveness of heavy-ion irradiation can be explained by linear energy transfer (LET; keV µm-1). Heavy-ion beams with different LET values induce different types and sizes of mutations. It has been suggested that deletion size increases with increasing LET value, and complex chromosomal rearrangements are induced in higher LET radiations. In this study, we mapped heavy-ion beam-induced deletions detected in Arabidopsis mutants to its genome. We revealed that deletion sizes were similar between different LETs (100 to 290 keV μm-1), that their upper limit was affected by the distribution of essential genes, and that the detected chromosomal rearrangements avoid disrupting the essential genes. We also focused on tandemly arrayed genes (TAGs), where two or more homologous genes are adjacent to one another in the genome. Our results suggested that 100 keV µm-1 of LET is enough to disrupt TAGs and that the distribution of essential genes strongly affects the heritability of mutations overlapping them. Our results provide a genomic view of large deletion inductions in the Arabidopsis genome.
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Characterization of a novel mutant with inhibition of storage root formation in sweet potato 査読あり
Hyungjun Park, Tomoko Abe, Hisato Kunitake, Tomonari Hirano
Breeding Science 73 ( 2 ) 212 - 218 2023年6月
担当区分：最終著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本育種学会
Sweet potato is a widely cultivated crop with storage roots. Although many studies have been conducted on the mechanism of its storage root formation, the details have not been fully elucidated. We screened mutant lines with inhibition of storage root formation to clarify parts of the mechanism. In this study, the process of storage root formation in one of the mutant lines, C20-8-1, was investigated. The inhibition of storage root formation was observed during the early stages of growth. The roots in C20-8-1 did not show histological differences compared to those in wild type. The transition from fibrous roots to pencil roots, which are the developmental stages prior to mature storage root formation, was delayed or inhibited in C20-8-1. The upregulation of starch biosynthesis-related genes and downregulation of lignin biosynthesis genes with storage root swelling were not confirmed in the root of C20-8-1 during the developmental transition stage, suggesting that most of the roots in C20-8-1 are in the pre-transition state toward the storage root swelling. C20-8-1 showed a mutant phenotype during the critical period of storage root swelling initiation, and further clarification of this mutation is expected to provide new insights into storage root formation.
DOI： 10.1270/jsbbs.22090
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Effect of Growth Stages on Anthocyanins and Polyphenols in the Root System of Sweet Potato. 査読あり
Setoguchi Y, Nakagawa S, Ohmura R, Toshima S, Park H, Narasako Y, Hirano T, Otani M, Kunitake H
Plants (Basel, Switzerland) 12 ( 9 ) 1907 2023年5月
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Amphidiploid production of hybrid between black raspberry and Rubus parvifolius L., a wild Asian species, using colchicine treatment 査読あり
Saki Toshima, Itsuki Katsumi, Arisa Kai, Masaki Yahata, Tomonari Hirano, Hisato Kunitake
Scientia Horticulturae 312 111863 2023年3月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Comparison of Proanthocyanidin Content in Rabbiteye Blueberry (Vaccinium virgatum Aiton) Leaves and the Promotion of Apoptosis against HL-60 Promyelocytic Leukemia Cells Using ‘Kunisato 35 Gou’ Leaf Extract 査読あり
Toyama, Yuki, Yoko Fujita, Saki Toshima, Tomonari Hirano, Masao Yamasaki, Hisato Kunitake
Plants 12 ( 4 ) 948 2023年2月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Comprehensive effects of heavy-ion beam irradiation on sweet potato (Ipomoea batatas [L.] Lam.) 査読あり
Park Hyungjun, Narasako Yosuke, Abe Tomoko, Kunitake Hisato, Hirano Tomonari
Plant Biotechnology 39 ( 3 ) 311 - 316 2022年9月
担当区分：最終著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本植物バイオテクノロジー学会
Sweet potato is a major root crop with nutritious tuberous roots. The mechanism of tuberous root development has not yet been adequately elucidated. Genetic resources are required to develop the molecular understanding of sweet potato. Heavy-ion beams were applied to hexaploid sweet potato for an increase in genetic variation, after which the comprehensive effects of heavy-ion beam irradiation were investigated. In vitro cultured shoots with an axillary bud of ‘Beniharuka’ were irradiated with Ar-ions at a dose of 1–5 Gy and C-ions at a dose of 5–20 Gy, and three irradiated lines were separated from each irradiated shoot. The shoot regeneration was inhibited at high doses of each ion irradiation. Ar-ion irradiation had an especially high biological effect on shoot regeneration. A total of 335 lines were obtained, consisting of 104 and 231 lines derived from Ar- and C-ion irradiation, respectively. The change in the DNA content of the lines was analyzed by flow cytometry to evaluate the irradiation-induced damage to the DNA. The two lines demonstrated significant differences in the DNA content and changes at the chromosome level. The screening for the morphological mutants was conducted in the field. Some irradiated lines showed inhibited or no tuberous root phenotype as mutant candidates. Additionally, the high-yield mutant candidates were dominated by Ar-ion irradiation. It was indicated that heavy-ion beam mutagenesis is effective in broadening the range of the phenotypes corresponding to tuberous root formation in hexaploid sweet potato.
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Nakagawa S., Setoguchi Y., Ohmura R., Toshima S., Park H., Narasako Y., Hirano T., Otani M., Kunitake H.
Scientia Horticulturae 299 110999 2022年6月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Scientia Horticulturae
Anthocyanins in sweetpotato (Ipomoea batatas L.) have attracted much attention in light of their multiple health benefits and excellent properties as processed foods. Although crossbreeding is an effective way to breed new cultivars of sweetpotato, there are few reports on how anthocyanin content and composition are passed on to F1 hybrid generations by crossbreeding because of a complex genome and self-incompatibility reactions. In this study, three purple-fleshed sweetpotao cultivars, ‘Akemurasaki’, ‘Kyushu No.137’, ‘Purple Sweet Lord’, and one yellow-fleshed cultivars, ‘HE306’ (Silk Sweet®) selected for their anthocyanin contents and compositions were crossed in six combinations. Flowering was induced by using a sweetpotato grafting technique to obtain a total of 143 F1 hybrid lines. Anthocyanin content, the percentage of acylated anthocyanins, and the peonidin/cyanidin ratio in each of these F1 hybrid lines were investigated. In the F1 hybrid generations derived from these six cross combinations, many lines tended to have anthocyanin contents similar to those of the parent cultivars. In particular, among the 36 hybrid lines derived from crosses between ‘Akemurasaki’ and ‘HE306’ (Silk Sweet®), 13 lines with high anthocyanin contents (≧200 mg·100 g FW−1) and 20 lines without anthocyanins were identified. The F1 hybrid lines of this combination had anthocyanin contents similar to those of the parent cultivars, with anthocyanin-free lines appearing more frequently than anthocyanin-containing lines. Interestingly, we also identified a line with an extremely low percentage of acylated anthocyanins (49.7%) from the F1 hybrid lines derived from a cross between ‘Purple Sweet Lord’ (seed parent) and ‘Kyushu No. 137’ (pollen parent). Moreover, the F1 hybrid lines derived from crosses between ‘Purple Sweet Lord’ and ‘Kyushu No.137’ tended to have high peonidin/cyanidin ratios. This study provides an example of the inheritance of anthocyanin content and its composition in sweetpotato, which supplies valuable information for selection of parents to breed purple-fleshed cultivars.
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DNA Damage Response of Cyrtanthus mackenii Male Gametes Following Argon Ion Beam Irradiation 査読あり
Tomonari Hirano, Yuka Matsuyama, Anna Hanada, Yoriko Hayashi, Tomoko Abe, Hisato Kunitake
CYTOLOGIA 86 ( 4 ) 311 - 315 2021年12月
担当区分：筆頭著者, 責任著者 記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益財団法人 日本メンデル協会
Heavy-ion beams have been applied as effective mutagens to various plant materials. Pollen has been used as material for mutant induction and genetic analysis. However, our knowledge of the DNA damage response of plant male gametes remains limited. In the present study, we irradiated <i>Cyrtanthus mackenii</i> pollen with an argon ion beam, which induced complex DNA damage, and investigated the DNA damage response of male gametes during pollen tube growth. Male gametes derived from the irradiated pollen grains were isolated from pollen tubes after 12 and 24 h of culture and subjected to cell cycle analysis. After 12 h of culture, the irradiated generative cells were frequently arrested at metaphase during pollen mitosis II (PMII), and the proportion of metaphase cells increased with increasing absorbed dose. These results suggest that the genomic lesions induced by the argon ion beam caused spindle assembly checkpoint (SAC)-dependent arrest. After 24 h of culture, the irradiated male gametes completed PMII, albeit forming sperm cells with abnormalities in chromosome separation, and chromosomal bridges were often formed between these cells. Moreover, phosphorylated H2AX foci, an indicator of DNA double-strand breaks, were detected in the irradiated male gametes after 24 h of culture, regardless of passing through the SAC. Taken together, these results indicate that male gametes activate functions to cope with radiation-induced complex DNA damage during pollen tube growth.
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Yoichi Sato, Tomonari Hirano, Yoriko Hayashi, Nobuhisa Fukunishi, Tomoko Abe, Shigeyuki Kawano
CYTOLOGIA 86 ( 4 ) 291 - 295 2021年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：公益財団法人 日本メンデル協会
In <i>Undaria pinnatifida</i>, an effective method for mutant screening in sporophytes has not been established. The present study developed a novel mutant screening method for <i>Undaria</i> sporophyte by combining gametophyte mutagenesis with heavy-ion beam and land-based tank culture system. When we irradiated gametophytes and sporophytes with carbon- and argon-ion beams, survival rates of the female gametophytes and the sporophytes decreased with increasing dose. However, those of the male gametophyte did not decrease after both of the irradiations. Mutant screening during the sporophyte development was performed by using a land-based tank culture system. High-growth plants were selected in the first mutant (M<sub>1</sub>) population derived from the irradiated materials. We successfully obtained mutant candidates with higher growth than the wild type in the M<sub>2</sub> generation obtained from brother-sister inbreeding of selected M<sub>1</sub> plants. Four high-growth mutant candidate lines were selected from M<sub>2</sub> populations of 48 lines. The mutant candidates were derived from 3 lines of the gametophyte irradiation and 1 line of the sporophyte irradiation, suggesting that the materials for the irradiation are applicable for mutant induction. The mutant screening method and the selected mutant candidates would advance the breeding and molecular biology in <i>U. pinnatifida</i>.
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Toyama Y., Toshima S., Hirano T., Yamasaki M., Kunitake H.
Journal of Berry Research 11 ( 4 ) 689 - 704 2021年12月
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Journal of Berry Research
BACKGROUND: In blueberries, the total polyphenol contents, total anthocyanin contents, and antioxidant activities of fruits in blueberries and their relatives are becoming important targets for breeders. Recently, intersectional hybrids between Japanese wild species Shashanbo and highbush blueberry were produced using polyploid breeding for the first time. However, the polyphenol contents, antioxidant activities, and anti-cancer cell proliferation properties of the fruits of these intersectional hybrids have not been studied sufficiently. OBJECTIVE: The objectives of this study were to determine the anthocyanin contents, polyphenol contents, and antioxidant activities at each stage of fruit development in intersectional hybrids, and to examine the effects of the fruit extracts on anti-cancer cell proliferation properties using human promyelocytic leukemia (HL-60) cells. METHODS: Freeze-dried fruit samples of three intersectional hybrids and their parents at five developmental stages were used to evaluate their polyphenol contents, anthocyanin contents, and levels of two types of antioxidant activities (DPPH and ORAC). The anti-cancer cell proliferation properties of each extract were also evaluated according to the survival rate of HL-60 cells. RESULTS: The total polyphenol contents in fruits of the intersectional hybrids gradually decreased as the fruits grew, but the contents increased slightly at the mature stage. Meanwhile, the total anthocyanin contents increased strongly to the mature stage. In addition, the fruit extract of intersectional hybrid JM1 was found to be more effective for inhibiting the growth of HL-60 human leukemia cells in vitro. Total polyphenol content correlated highly with antioxidant activities and anti-cancer cell proliferation properties. CONCLUSIONS: We clarified that the intersectional hybrids had produced have abundant bioactive compounds, high levels of antioxidant activities, and anti-cancer cell proliferation properties. The results proved the effectiveness of the use of Japanese wild Vaccinium species for the strategic breeding of blueberries with high levels of bioactive compounds.
DOI： 10.3233/JBR-210713
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Extending the cultivation period of Undaria pinnatifida by using regional strains with phenotypic differentiation along the Sanriku coast in northern Japan 査読あり
Yoichi Sato,Tomonari Hirano,Hiroyuki Ichida,Nobuhisa Fukunishi,Tomoko Abe, Shigeyuki Kawano
Phycology 1 ( 2 ) 129 - 142 2021年12月
記述言語：英語 掲載種別：研究論文（学術雑誌）
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Fruit Qualities of Interspecific Hybrid and First Backcross Generations between Red Raspberry and Rubus parvifolius 査読あり
Saki Toshima, Marika Fujii, Momoko Hidaka, Soya Nakagawa, Tomonari Hirano, Hisato Kunitak
Journal of the American Society for Horticultural Science 146 ( 6 ) 445 - 451 2021年10月
記述言語：英語 掲載種別：研究論文（学術雑誌）