Research activity information

• Sep. 2026 日本土壌肥料学会, 若手口頭発表優秀賞, 鉄依存的な活性酸素（ROS）毒性が引き起こす柵状組織特異的な葉の白化

  竹内 航・加藤優太・落合久美子・小林 優・小林康一・三宅親弘・伊福健太郎


• 2026 日本植物学会, 若手奨励賞, 植物の低温耐性を支える葉緑体ROS障害の抑制機構の解明

  竹内 航


• Sep. 2025 日本土壌肥料学会, ポスター発表優秀賞, 鉄動態が植物の低温ストレス耐性に及ぼす影響

  竹内航、落合久美子、小林優、伊福健太郎

• The PSI‐NDH supercomplex prevents chilling‐induced PSI photoinhibition

  Ko Takeuchi, Shintaro Harimoto, Kentaro Ifuku

  Lead, Nov. 2026, New Phytologist

  [Refereed]

  Scientific journal


• Tissue-resolved photosynthetic responses in living leaves revealed by microscopic imaging-pulse-amplitude-modulation

  Yuta Kato, Ko Takeuchi, Shintaro Harimoto, Koich Kobayashi, Kentaro Ifuku

  Sep. 2026


• 葉緑体の保護による作物の低温耐性メカニズム

  竹内航, 伊福健太郎

  Lead, May 2026, バイオサイエンスとインダストリー (B&I), 84(3) (3), 268 - 269

  [Refereed][Invited]

  Scientific journal


• 冬でも元気なキュウリへ：鉄栄養と光合成が拓く低温耐性機構

  竹内 航, 伊福 健太郎

  Lead, Mar. 2026, 月刊アグリバイオ, 239(10) (10), 65 - 67


• The protective role of chloroplast NADH dehydrogenase‐like complex (NDH) against PSI photoinhibition under chilling stress

  Ko Takeuchi, Shintaro Harimoto, Yufen Che, Minoru Kumazawa, Hayato Satoh, Shu Maekawa, Chikahiro Miyake, Kentaro Ifuku

  SummaryChilling stress induces photosystem I (PSI) photoinhibition in various plants, severely impairing their growth. However, the mechanisms suppressing chilling-induced PSI photoinhibition remain unclear. This study aimed to identify factors preventing PSI photoinhibition by comparing two cucumber cultivars with different susceptibilities to PSI photoinhibition and chilling stress tolerance. In the chilling-sensitive cultivar, partial degradation of the CF1-γ subunit of chloroplast ATPase led to uncoupling of the thylakoid membrane. In addition, electron efflux from Fe-S clusters downstream of PSI was restricted under chilling stress, resulting in highly reduced Fe-S clusters. Notably, this PSI over-reduction in the chilling-sensitive cultivar was observed not only under chilling stress but also under fluctuating light conditions, limited CO2conditions, and during the transition from darkness to light, suggesting that cyclic electron flow contributes to cultivar differences in PSI photoinhibition. Indeed, the chilling-tolerant cultivar exhibited higher activity of the chloroplast NADH dehydrogenase-like complex (NDH) and suppressed reactive oxygen species (ROS) accumulation during the early stages of chilling stress. In contrast, in the chilling-sensitive cultivar, destabilization of PSI–NDH supercomplex under chilling stress led to the loss of NDH activity, resulting in severe PSI over-reduction. This study provides evidence that NDH acts as a crucial electron sink to prevent PSI photoinhibition and provides new insights into the mechanisms underlying low-temperature stress tolerance.

  Lead, Dec. 2025, New Phytologist

  [Refereed]

  Scientific journal


• PSII Photoinhibition as a Protective Strategy: Maintaining an Oxidative State of PSI by Suppressing PSII Activity Under Environmental Stress

  Ko Takeuchi, Shintaro Harimoto, Shu Maekawa, Chikahiro Miyake, Kentaro Ifuku

  ABSTRACT Photosystem I (PSI) can be photoinhibited by excessive electron flow from Photosystem II (PSII), causing serious growth inhibition due to PSI's limited repair capacity. In contrast, PSII is more prone to photoinhibition under environmental stress, but it can recover efficiently. Consequently, PSII photoinhibition is considered a protective mechanism that mitigates PSI over‐reduction. However, this photoprotective role under environmental stress remains unexplored in intact plants without using mutants or chemical treatments. To address this, we examined the relationship between PSII photoinhibition and PSI protection under two representative stresses that selectively induce PSI photoinhibition: chilling stress and fluctuating light, using A. thaliana and cucumber plants. Under chilling stress, A. thaliana exhibited marked PSII photoinhibition and maintained active PSI, whereas cucumber showed insufficient PSII downregulation and suffered from PSI photoinhibition. In addition, when fluctuating light treatment was applied to plants with various Fv/Fm (the maximum quantum yield of PSII), plants with reduced Fv/Fm maintained an oxidized PSI, and PSI photoinhibition progressed slowly. The susceptibility to PSI photoinhibition under fluctuating light strongly correlated with Fv/Fm, providing clear evidence that PSII photoinhibition protects PSI. Interestingly, even in plants where P700 remained oxidized due to PSII photoinhibition, the Fe‐S clusters remained reduced during saturation pulses. However, the re‐oxidation of reduced Fe‐S clusters was enhanced in PSII‐photoinhibited plants, suggesting that charge recombination to P700⁺ with reduced components on the PSI acceptor side or accelerated processes downstream of ferredoxin would suppress ROS generation downstream of PSI. This study clarifies how PSII photoinhibition suppresses PSI photoinhibition and prevents ROS‐induced damage under environmental stresses.

  Lead, Wiley, Jul. 2025, Physiologia Plantarum, 177(4) (4)

  [Refereed]

  Scientific journal


• Light-chilling stress causes hyper-accumulation of iron in shoot, exacerbating leaf oxidative damage in cucumber.

  Ko Takeuchi, Kumiko Ochiai, Masaru Kobayashi, Kouichi Kuroda, Kentaro Ifuku

  Iron availability within the root system of plants fluctuates depending on various soil factors, which directly impacts plant growth. Simultaneously, various environmental stressors, such as high/low temperatures and high light intensity, affect plant photosynthesis in the leaves. However, the combined effects of iron nutrient conditions and abiotic stresses have not yet been clarified. In this study, we analyzed how iron nutrition conditions impact the chilling-induced damage on cucumber leaves (Cucumis sativus L.). When cucumbers were grown under different iron conditions and then exposed to chilling stress, plants grown under a high-iron condition exhibited more severe chilling-induced damage than the control plants. Conversely, plants grown under a low iron condition showed an alleviation of the chilling-induced damages. These differences were observed in a light-dependent manner, indicating that iron intensified the toxicity of reactive oxygen species generated by photosynthetic electron transport. In fact, plants grown under the low iron condition showed less accumulation of malondialdehyde derived from lipid peroxidation after chilling stress. Notably, the plants grown under the high-iron condition displayed a significant accumulation of iron and an increase in lipid peroxidation in the shoot, specifically after light-chilling stress, but not after dark-chilling stress. This indicated that increased root-to-shoot iron translocation, driven by light and low temperature, exacerbated leaf oxidative damage during chilling stress. These findings also highlight the importance of managing iron nutrition in the face of chilling stress and will facilitate crop breeding and cultivation strategies.

  Lead, Sep. 2024, Plant & Cell Physiology, English, Domestic magazine

  [Refereed]

  Scientific journal


• The ability of P700 oxidation in photosystem I reflects chilling stress tolerance in cucumber.

  Ko Takeuchi, Yufen Che, Takeshi Nakano, Chikahiro Miyake, Kentaro Ifuku

  Low temperature inhibits photosynthesis and negatively affects plant growth. Cucumber (Cucumis sativus L.) is a chilling-sensitive plant, and its greenhouse production requires considerable energy during the winter. Therefore, a useful stress marker for selecting chilling-tolerant cucumber cultivars is desirable. In this study, we evaluated chilling-stress damage in different cucumber cultivars by measuring photosynthetic parameters. The majority of cultivars showed decreases in the quantum yield of photosystem (PS) II [Fv/Fm and Y(II)] and the quantity of active PS I (Pm) after chilling stress. In contrast, Y(ND)-the ratio of the oxidized state of PSI reaction center chlorophyll P700 (P700+)-differed among cultivars and was perfectly inversely correlated with Y(NA)-the ratio of the non-photooxidizable P700. It has been known that P700+ accumulates under stress conditions and protects plants to suppress the generation of reactive oxygen species. In fact, cultivars unable to induce Y(ND) after chilling stress showed growth retardation with reductions in chlorophyll content and leaf area. Therefore, Y(ND) can be a useful marker to evaluate chilling-stress tolerance in cucumber.

  Lead, Sep. 2022, Journal of Plant Research, 135(5) (5), 681 - 692, English, Domestic magazine

  [Refereed]

  Scientific journal

• 鉄依存的な活性酸素 (ROS) 毒性が引き起こす柵状組織特異的な葉の白化

  竹内 航, 加藤 優太, 落合 久美子, 小林 優, 小林 康一, 三宅 親弘, 伊福 健太郎

  日本土壌肥料学会 東北大会, Sep. 2026


• 植物の低温耐性を支える 葉緑体ROS障害の抑制機構の解明

  竹内航

  日本植物学会 若手奨励賞受賞公演, Sep. 2026

  [Invited]

  Invited oral presentation


• Chloroplast NDH protects photosystem I from photoinhibition under chilling stress

  Ko TAKEUCHI, Shintaro HARIMOTO, Hayato SATOH, Chikahiro MIYAKE, Kentaro IFUKU

  International Conference on Photosyntheis Research 2026, Jul. 2026


• キュウリはなぜ冬に育たないのか？―光合成と栄養から考える低温ストレス耐性―

  竹内航

  生体膜国際研究拠点形成セミナー(神戸), Jun. 2026

  [Invited]

  Invited oral presentation


• 低温光阻害に伴う活性酸素（ROS）は鉄依存的に柵状組織の白化を引き起こす

  竹内 航, 加藤 優太, 落合 久美子, 小林 優, 小林 康一, 三宅 親弘, 伊福 健太郎

  日本光合成学会, May 2026


• PSI-NDH超複合体による低温PSI光阻害の抑制

  竹内航, 播本慎太郎, 佐藤勇斗, 三宅親弘, 伊福健太郎

  第66回 日本植物生理学会年会 2026年3月


• 鉄動態が植物の低温ストレス耐性に及ぼす影響

  竹内航, 落合久美子, 小林優, 伊福健太郎

  日本土壌肥料学会 新潟大会, Sep. 2025


• 低温PSI光阻害に対する葉緑体NDHの役割

  竹内 航, 播本 慎太郎, 車 玉芬, 三宅 親弘, 伊福 健太郎

  第15回日本光合成学会, Jun. 2025


• Different strategies to keep photosystem I oxidized during chilling stress among plant species

  竹内航, 播本慎太郎, 三宅親弘, 伊福健太郎

  日本植物生理学会 金沢, Mar. 2025


• Effects of iron nutrition on chilling stress tolerance

  Ko Takeuchi, Kumiko Ochiai, Masaru Kobayashi, Kentaro Ifuku

  The 7th KU-KUGSA Symposium on Food, Environment and Life for the Next Generation: Science and Technology for Bio-Circular-Green Economy, Dec. 2024


• Mechanisms causing varietal differences of photosystem I inhibition in cucumber under low-temperature stress

  Ko Takeuchi, Shintaro Harimoto, Yufen Che, Shu Maekawa, Chikahiro Miyake, Kentaro Ifuku

  2nd Asia-Oceania International Congress on Photosynthesis (AOICP), 2024

  Poster presentation


• キュウリ低温ストレス時のPSI光阻害の抑制に代替的電子伝達が重要である

  竹内航, 播本慎太郎, 前河秀, 車玉芬, 三宅親弘, 伊福健太郎

  日本植物学会 宇都宮, 2024

  Oral presentation


• Effects of photoinhibition and iron nutrition on chilling stress tolerance in cucumber

  Ko Takeuchi, Kumiko Ochiai, Masaru Kobayashi, Kouichi Kuroda, Kentaro Ifuku

  13th International Plant Cold Hardiness Seminar (France), 2024

  Poster presentation


• 飽和パルス光を用いた低温ストレス時の光化学系Iへの電子流入量と光化学系I光阻害の評価

  竹内航, 播本慎太郎, 和田慎也, 三宅親弘, 伊福健太

  植物生理学会 神戸, 2024


• 低温ストレス耐性における活性酸素 および鉄栄養の影響

  竹内 航, 落合 久美子, 小林 優, 黒田 浩一, 伊福 健太郎

  日本植物学会 北海道大会, 2023

  Oral presentation


• 鉄と活性酸素が植物の 低温ストレス障害に及ぼす影響

  竹内 航, 落合 久美子, 小林 優, 黒田 浩一, 伊福 健太郎

  日本土壌肥料学会 愛媛大会, 2023


• 鉄栄養状態は植物低温ストレス耐性に密接に関わる

  竹内航, 落合久美子, 小林優, 黒田浩一, 伊福健太郎

  植物の栄養研究会, 2023


• キュウリ低温ストレス障害における活性酸素と鉄の影響

  竹内 航, 車 玉芬, 中野 雄司, 伊福 健太郎

  第64回 日本植物生理学会年会, 2023

  Oral presentation


• 低温ストレス障害と光化学系Iストレス応答との関わり

  竹内航, 車玉芬, 熊沢穣, 中野雄司, 三宅親弘, 伊福健太

  日本植物生理学会, 2022

  Oral presentation


• Evaluation of cucumber chilling stress tolerance by P700 oxidation analysis in photosystem I

  Ko Takeuchi, Yufen Che, Takeshi Nakano, Chikahiro Miyake, Kentaro Ifuku

  International Symposium on Photosynthesis and Chloroplast Regulation

  Oral presentation


• 低温ストレス耐性における光化学系IのP700酸化の役割

  竹内 航, 車 玉芬, 熊沢 穣, 大畠 和真, 中野 雄司, 三宅 親弘, 伊福 健太郎

  日本植物学会第86回大会

  Oral presentation


• 光化学系IのP700酸化能力とキュウリ低温ストレス耐性の密接な関わり

  竹内 航, 車 玉芬, 熊沢 穣, 大畠 和真, 中野 雄司, 三宅 親弘, 伊福 健太郎

  第12回 日本光合成学会年会およびシンポジウム

  Oral presentation


• 光化学系IのP700酸化能力の違いがキュウリの低温感受性の品種間差を引き起こす

  竹内 航, 車 玉芬, 熊沢 穣, 中野 雄司, 三宅 親弘, 伊福 健太郎

  日本植物生理学会2021

  Oral presentation

• 日本光合成学会

  2024 - Present


• 日本土壌肥料学会

  2023 - Present


• 日本植物学会

  2022 - Present


• 植物生理学会

  2021 - Present

• 「葉緑体フェロトーシス」の解明による作物の環境ストレス耐性向上

  ロッテ財団, 奨励研究助成【A】個人研究, Apr. 2027 - Mar. 2029, Principal investigator


• 高温・低温ストレス下の葉緑体ROSダイナミクス解析による葉緑体分解機構の解明

  日本学術振興会 科学研究費助成事業 特別研究員奨励費, Apr. 2026


• Importance of quantitative and qualitative control of ROS production in plant chilling stress tolerance

  竹内 航

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for JSPS Fellows, Kyoto University, 25 Apr. 2023 - 31 Mar. 2026

• 生物学オリンピック 研究体験 光合成イメージング

  Lecturer, 20 Aug. 2026

• 日本発の発見から約30年 植物の低温光阻害を引き起こす新たな分子機構を解明

  神戸大学・京都大学, https://www.kyoto-u.ac.jp/ja/research-news/2026-09-25-2, Sep. 2026

  Internet


• 植物の低温耐性を支える新たなメカニズムを発見―葉緑体の活性酸素ダメージの軽減機構―

  Myself, 京都大学プレスリリース

  Internet