Details of the Researcher

PHOTO

Shinya Wada
Section
Graduate School of Agricultural Science
Job title
Associate Professor
Degree

Research History 1

  • 2024/04 - Present
    Tohoku University　Graduate School of Agricultural Science　Associate Professor

Professional Memberships 3

  • The Japanese Society of Photosynthesis Research

    2023/05 - Present

  • The japanese society of plant physiologists

    2006 - Present

  • Japanese society of soil science and plant nutrition

    2005 - Present

Research Interests 6

  • Photorespiration

  • electron transport

  • autophagy

  • protein degradation

  • photosynthesis

  • leaf senescence

Research Areas 2

  • Life sciences / Plants: molecular biology and physiology / Photosynthesis, Photorespiration

  • Life sciences / Plant nutrition, soil science / Nitrogen recycling, Protein degradation, Photosynthesis, Photorespiration

Awards 1

  1. Encouragement award from the Japanese society of soil science and plant nutrition

    2017/09　Japanese society of soil science and plant nutrition

Papers 48

  1. Regulation of photosystems II and I depending on N partitioning to Rubisco in rice leaves: a study using Rubisco-antisense transgenic plants.

    Yuta Nakamura, Shinya Wada, Chikahiro Miyake, Amane Makino, Yuji Suzuki

    Journal of plant research　137　(6)　1165-1175　2024/11

    DOI： 10.1007/s10265-024-01582-9 　

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    We have previously suggested that in rice (Oryza sativa L.) leaves of different ages and N nutrition statuses, photosystems II and I (PSII and PSI, respectively) are regulated depending on N partitioning to Rubisco, which can determine the magnitude of unutilized light energy. The robustness of this mechanism was tested using Rubisco-antisense transgenic rice plants, in which reduced N partitioning to Rubisco markedly increases unutilized light energy. In wild-type plants, N partitioning to Rubisco tended to be smaller in the leaves at lower positions owing to leaf senescence. In the transgenic plants, N partitioning to Rubisco was generally smaller than in the wild-type plants and was relatively constant among leaf positions. The quantum efficiency of PSII [Y(II)] and quantum yield of non-photochemical quenching [Y(NPQ)] correlated positively and negatively, respectively, with N partitioning to Rubisco irrespective of leaf position or genotype. The oxidation levels of the reaction center chlorophyll of PSI (P700) [Y(ND)] negatively correlated with N partitioning to Rubisco. However, in mature and early senescent leaves of the transgenic plants, Y(ND) was markedly lower than expected from N partitioning to Rubisco. These results suggest that in the transgenic plants, the regulation depending on N partitioning to Rubisco is robust for PSII but fails for PSI in mature and early senescing leaves. In these leaves, the magnitudes of P700 oxidation were found to be less than expected from the Y(II) and Y(NPQ) values. The mechanistic reasons and physiological implications of these phenomena are discussed.

  2. Enhanced Reduction of Ferredoxin in PGR5-deficient mutant of<em> Arabidopsis thaliana</em> Stimulated Ferredoxin-dependent Cyclic Electron Flow around Photosystem I International-journal

    Shu Maekawa, Miho Ohnishi, Shinya Wada, Kentaro Ifuku, Miyake Chikahiro

    International Journal of Molecular Sciences　25　(5)　2024/02

    DOI： 10.20944/preprints202401.1303.v1 　

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    The molecular entity responsible for catalyzing ferredoxin (Fd)-dependent cyclic electron flow around photosystem I (Fd-CEF) remains unidentified. To reveal the in vivo molecular mechanism of Fd-CEF, evaluating ferredoxin reduction-oxidation kinetics proves to be a reliable indicator of Fd-CEF activity. Recent research has demonstrated that the expression of Fd-CEF activity is contingent upon the oxidation of plastoquinone. Moreover, chloroplast NAD(P)H dehydrogenase does not catalyze Fd-CEF in Arabidopsis thaliana. In this study, we analyzed the impact of reduced Fd on Fd-CEF activity by comparing wild-type and pgr5-deficient mutants (pgr5hope1). PGR5 has been proposed as the mediator of Fd-CEF, and pgr5hope1 exhibited a comparable CO2 assimilation rate and the same reduction-oxidation level of PQ as the wild type. However, P700 oxidation was suppressed with highly reduced Fd in pgr5hope1, unlike in the wild type. As anticipated, the Fd-CEF activity was enhanced in pgr5hope1 compared to the wild type, and its activity further increased with the oxidation of PQ due to the elevated CO2 assimilation rate. This in vivo research clearly demonstrates that the expression of Fd-CEF activity requires not only reduced Fd but also oxidized PQ. Importantly, PGR5 was found to not catalyze Fd-CEF, challenging previous assumptions about its role in this process.

  3. Evaluating the Oxidation Rate of Reduced Ferredoxin in Arabidopsis thaliana Independent of Photosynthetic Linear Electron Flow: Plausible Activity of Ferredoxin-Dependent Cyclic Electron Flow around Photosystem I International-journal

    Miho Ohnishi, Shu Maekawa, Shinya Wada, Kentaro Ifuku, Chikahiro Miyake

    International Journal of Molecular Sciences　24　(15)　2023/07

    DOI： 10.3390/ijms241512145 　

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    The activity of ferredoxin (Fd)-dependent cyclic electron flow (Fd-CEF) around photosystem I (PSI) was determined in intact leaves of Arabidopsis thaliana. The oxidation rate of Fd reduced by PSI (vFd) and photosynthetic linear electron flow activity are simultaneously measured under actinic light illumination. The vFd showed a curved response to the photosynthetic linear electron flow activity. In the lower range of photosynthetic linear flow activity with plastoquinone (PQ) in a highly reduced state, vFd clearly showed a linear relationship with photosynthetic linear electron flow activity. On the other hand, vFd increased sharply when photosynthetic linear electron flow activity became saturated with oxidized PQ as the net CO2 assimilation rate increased. That is, under higher photosynthesis conditions, we observed excess vFd resulting in electron flow over photosynthetic linear electron flow. The situation in which excess vFd was observed was consistent with the previous Fd-CEF model. Thus, excess vFd could be attributed to the in vivo activity of Fd-CEF. Furthermore, the excess vFd was also observed in NAD(P)H dehydrogenase-deficient mutants localized in the thylakoid membrane. The physiological significance of the excessive vFd was discussed.

  4. Behavior of Photosystems II and I Is Modulated Depending on N Partitioning to Rubisco in Mature Leaves Acclimated to Low N Levels and Senescent Leaves in Rice

    Yuji Suzuki, Kaho Ohsaki, Yuki Takahashi, Shinya Wada, Chikahiro Miyake, Amane Makino

    Plant &amp; cell physiology　64　(1)　55-63　2023/02/16

    DOI： 10.1093/pcp/pcac139 　

    eISSN： 1471-9053

  5. Effects of drought stress on the oxidation of the reaction center chlorophyll of photosystem I and grain yield in paddy-field grown rice plants

    Yuki Takahashi, Ko Noguchi, Kentaro Ifuku, Takayuki Sohtome, Takashi Nishimoto, Shinya Wada, Toshihiro Sato, Yuki Takegahara-Tamakawa, Chikahiro Miyake, Amane Makino, Yuji Suzuki

    Soil Science and Plant Nutrition　69　(4)　215-220　2023

    DOI： 10.1080/00380768.2023.2214579 　

    ISSN： 0038-0768

    eISSN： 1747-0765

  6. Higher Reduced State of Fe/S-Signals, with the Suppressed Oxidation of P700, Causes PSI Inactivation in Arabidopsis thaliana International-journal

    Riu Furutani, Shinya Wada, Kentaro Ifuku, Shu Maekawa, Chikahiro Miyake

    Antioxidants　12　(1)　21-21　2022/12/22

    Publisher: MDPI AG

    DOI： 10.3390/antiox12010021 　

    eISSN： 2076-3921

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    Environmental stress increases the risk of electron accumulation in photosystem I (PSI) of chloroplasts, which can cause oxygen (O2) reduction to superoxide radicals and decreased photosynthetic ability. We used three Arabidopsis thaliana lines: wild-type (WT) and the mutants pgr5hope1 and paa1-7/pox1. These lines have different reduced states of iron/sulfur (Fe/S) signals, including Fx, FA/FB, and ferredoxin, the electron carriers at the acceptor side of PSI. In the dark, short-pulse light was repetitively illuminated to the intact leaves of the plants to provide electrons to the acceptor side of PSI. WT and pgr5hope1 plants showed full reductions of Fe/S during short-pulse light and PSI inactivation. In contrast, paa1-7/pox1 showed less reduction of Fe/S and its PSI was not inactivated. Under continuous actinic-light illumination, pgr5hope1 showed no P700 oxidation with higher Fe/S reduction due to the loss of photosynthesis control and PSI inactivation. These results indicate that the accumulation of electrons at the acceptor side of PSI may trigger the production of superoxide radicals. P700 oxidation, responsible for the robustness of photosynthetic organisms, participates in reactive oxygen species suppression by oxidizing the acceptor side of PSI.

  7. Suppression of chloroplast triose phosphate isomerase evokes inorganic phosphate-limited photosynthesis in rice International-journal

    Yuji Suzuki, Keiki Ishiyama, Dong-Kyung Yoon, Yuki Takegahara-Tamakawa, Eri Kondo, Mao Suganami, Shinya Wada, Chikahiro Miyake, Amane Makino

    Plant Physiology　188　(3)　1550-1562　2022/03/04

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/plphys/kiab576 　

    ISSN： 0032-0889

    eISSN： 1532-2548

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    Abstract The availability of inorganic phosphate (Pi) for ATP synthesis is thought to limit photosynthesis at elevated [CO2] when Pi regeneration via sucrose or starch synthesis is limited. We report here another mechanism for the occurrence of Pi-limited photosynthesis caused by insufficient capacity of chloroplast triose phosphate isomerase (cpTPI). In cpTPI-antisense transgenic rice (Oryza sativa) plants with 55%–86% reductions in cpTPI content, CO2 sensitivity of the rate of CO2 assimilation (A) decreased and even reversed at elevated [CO2]. The pool sizes of the Calvin–Benson cycle metabolites from pentose phosphates to 3-phosphoglycerate increased at elevated [CO2], whereas those of ATP decreased. These phenomena are similar to the typical symptoms of Pi-limited photosynthesis, suggesting sufficient capacity of cpTPI is necessary to prevent the occurrence of Pi-limited photosynthesis and that cpTPI content moderately affects photosynthetic capacity at elevated [CO2]. As there tended to be slight variations in the amounts of total leaf-N depending on the genotypes, relationships between A and the amounts of cpTPI were examined after these parameters were expressed per unit amount of total leaf-N (A/N and cpTPI/N, respectively). A/N at elevated [CO2] decreased linearly as cpTPI/N decreased before A/N sharply decreased, owing to further decreases in cpTPI/N. Within this linear range, decreases in cpTPI/N by 80% led to decreases up to 27% in A/N at elevated [CO2]. Thus, cpTPI function is crucial for photosynthesis at elevated [CO2].

  8. Expression of flavodiiron protein rescues defects in electron transport around PSI resulting from overproduction of Rubisco activase in rice International-journal

    Mao Suganami, So Konno, Ryo Maruhashi, Daisuke Takagi, Youshi Tazoe, Shinya Wada, Hiroshi Yamamoto, Toshiharu Shikanai, Hiroyuki Ishida, Yuji Suzuki, Amane Makino

    Journal of Experimental Botany　73　(8)　2589-2600　2022/02/02

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/jxb/erac035 　

    ISSN： 0022-0957

    eISSN： 1460-2431

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    Abstract Fragility of photosystem I has been observed in transgenic rice plants that overproduce Rubisco activase (RCA). In this study, we examined the effects of RCA overproduction on the sensitivity of PSI to photoinhibition in three lines of plants overexpressing RCA (RCA-ox). In all the RCA-ox plants the quantum yield of PSI [Y(I)] decreased whilst in contrast the quantum yield of acceptor-side limitation of PSI [Y(NA)] increased, especially under low light conditions. In the transgenic line with the highest RCA content (RCA-ox 1), the quantum yield of PSII [Y(II)] and CO2 assimilation also decreased under low light. When leaves were exposed to high light (2000 μmol photon m−2 s−1) for 60 min, the maximal activity of PSI (Pm) drastically decreased in RCA-ox 1. These results suggested that overproduction of RCA disturbs PSI electron transport control, thus increasing the susceptibility of PSI to photoinhibition. When flavodiiron protein (FLV), which functions as a large electron sink downstream of PSI, was expressed in the RCA-ox 1 background (RCA-FLV), PSI and PSII parameters, and CO2 assimilation were recovered to wild-type levels. Thus, expression of FLV restored the robustness of PSI in RCA-ox plants.

  9. The difficulty of estimating the electron transport rate at photosystem I Peer-reviewed

    Riu Furutani, Miho Ohnishi, Yuki Mori, Shinya Wada, Chikahiro Miyake

    Journal of Plant Research　135　(4)　565-577　2021/11/15

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s10265-021-01357-6 　

    ISSN： 0918-9440

    eISSN： 1618-0860

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    It is still a controversial issue how the electron transport reaction is carried out around photosystem I (PSI) in the photosynthetic electron transport chain. The measurable component in PSI is the oxidized P700, the reaction center chlorophyll in PSI, as the absorbance changes at 820-830 nm. Previously, the quantum yield at PSI [Y(I)] has been estimated as the existence probability of the photo-oxidizable P700 by applying the saturated-pulse illumination (SP; 10,000-20,000 µmol photons m-2 s-1). The electron transport rate (ETR) at PSI has been estimated from the Y(I) value, which was larger than the reaction rate at PSII, evaluated as the quantum yield of PSII, especially under stress-conditions such as CO2-limited and high light intensity conditions. Therefore, it has been considered that the extra electron flow at PSI was enhanced at the stress condition and played an important role in dealing with the excessive light energy. However, some pieces of evidence were reported that the excessive electron flow at PSI would be ignorable from other aspects. In the present research, we confirmed that the Y(I) value estimated by the SP method could be easily misestimated by the limitation of the electron donation to PSI. Moreover, we estimated the quantitative turnover rate of P700+ by the light-to-dark transition. However, the turnover rate of P700 was much slower than the ETR at PSII. It is still hard to quantitatively estimate the ETR at PSI by the current techniques.

  10. Identification of a Novel Mutation Exacerbated the PSI Photoinhibition in pgr5/pgrl1 Mutants; Caution for Overestimation of the Phenotypes in Arabidopsis pgr5-1 Mutant International-journal Peer-reviewed

    Shinya Wada, Katsumi Amako, Chikahiro Miyake

    Cells　10　(11)　2884-2884　2021/10/26

    Publisher: MDPI AG

    DOI： 10.3390/cells10112884 　

    eISSN： 2073-4409

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    PSI photoinhibition is usually avoided through P700 oxidation. Without this protective mechanism, excess light represents a potentially lethal threat to plants. PGR5 is suggested to be a major component of cyclic electron transport around PSI and is important for P700 oxidation in angiosperms. The known Arabidopsis PGR5 deficient mutant, pgr5-1, is incapable of P700 oxidation regulation and has been used in numerous photosynthetic studies. However, here it was revealed that pgr5-1 was a double mutant with exaggerated PSI photoinhibition. pgr5-1 significantly reduced growth compared to the newly isolated PGR5 deficient mutant, pgr5hope1. The introduction of PGR5 into pgr5-1 restored P700 oxidation regulation, but remained a pale-green phenotype, indicating that pgr5-1 had additional mutations. Both pgr5-1 and pgr5hope1 tended to cause PSI photoinhibition by excess light, but pgr5-1 exhibited an enhanced reduction in PSI activity. Introducing AT2G17240, a candidate gene for the second mutation into pgr5-1 restored the pale-green phenotype and partially restored PSI activity. Furthermore, a deficient mutant of PGRL1 complexing with PGR5 significantly reduced PSI activity in the double-deficient mutant with AT2G17240. From these results, we concluded that AT2G17240, named PSI photoprotection 1 (PTP1), played a role in PSI photoprotection, especially in PGR5/PGRL1 deficient mutants.

  11. 9 イネにおける内在的なCO2固定反応効率の変動と光呼吸によるP700 酸化誘導（関西支部講演会 2020年度支部講演会）

    古谷 吏侑, 牧野 周, 鈴木 雄二, 嶋川 銀河, 和田 慎也, 三宅 親弘

    日本土壌肥料学会講演要旨集　67　220-220　2021/09/03

    Publisher: 一般社団法人 日本土壌肥料学会

    DOI： 10.20710/dohikouen.67.0_220_3 　

    ISSN： 0288-5840

    eISSN： 2424-0575

  12. Photosynthetic Parameters Show Specific Responses to Essential Mineral Deficiencies International-journal

    Miho Ohnishi, Riu Furutani, Takayuki Sohtome, Takeshi Suzuki, Shinya Wada, Soma Tanaka, Kentaro Ifuku, Daisei Ueno, Chikahiro Miyake

    Antioxidants　10　(7)　996-996　2021/06/23

    Publisher: MDPI AG

    DOI： 10.3390/antiox10070996 　

    eISSN： 2076-3921

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    In response to decreases in the assimilation efficiency of CO2, plants oxidize the reaction center chlorophyll (P700) of photosystem I (PSI) to suppress reactive oxygen species (ROS) production. In hydro-cultured sunflower leaves experiencing essential mineral deficiencies, we analyzed the following parameters that characterize PSI and PSII: (1) the reduction-oxidation states of P700 [Y(I), Y(NA), and Y(ND)]; (2) the relative electron flux in PSII [Y(II)]; (3) the reduction state of the primary electron acceptor in PSII, QA (1 − qL); and (4) the non-photochemical quenching of chlorophyll fluorescence (NPQ). Deficiency treatments for the minerals N, P, Mn, Mg, S, and Zn decreased Y(II) with an increase in the oxidized P700 [Y(ND)], while deficiencies for the minerals K, Fe, Ca, B, and Mo decreased Y(II) without an increase in Y(ND). During the induction of photosynthesis, the above parameters showed specific responses to each mineral. That is, we could diagnose the mineral deficiency and identify which mineral affected the photosynthesis parameters.

  13. Effects of co-overproduction of Rubisco and chloroplast glyceraldehyde-3-phosphate dehydrogenase on photosynthesis in rice

    Yuji Suzuki, Keiki Ishiyama, Ayaka Cho, Yuki Takegahara-Tamakawa, Shinya Wada, Chikahiro Miyake, Amane Makino

    Soil Science and Plant Nutrition　1-5　2021/04/17

    Publisher: Informa UK Limited

    DOI： 10.1080/00380768.2021.1915100 　

    ISSN： 0038-0768

    eISSN： 1747-0765

  14. Photochemistry of Photosystems II and I in Rice Plants Grown under Different N Levels at Normal and High Temperature

    Yuki Takahashi, Shinya Wada, Ko Noguchi, Chikahiro Miyake, Amane Makino, Yuji Suzuki

    Plant and Cell Physiology　62　(7)　1121-1130　2021/02/09

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/pcp/pcab020 　

    ISSN： 0032-0781

    eISSN： 1471-9053

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    <title>Abstract</title> Although N levels affect leaf photosynthetic capacity, the effects of N levels on the photochemistry of photosystems II and I (PSII and PSI, respectively) are not well-understood. In the present study, we examined this aspect in rice (Oryza sativa L. ‘Hitomebore’) plants grown under three different N levels at normal or high temperatures that can occur during rice culture and do not severely suppress photosynthesis. At both growth temperatures, the quantum efficiency of PSII [Y(II)] and the fraction of the primary quinone electron acceptor in its oxidized state were positively correlated with the amount of total leaf-N, whereas the quantum yields of non-photochemical quenching and donor-side limitation of PSI [Y(ND)] were negatively correlated with the amount of total leaf-N. These changes in PSII and PSI parameters were strongly correlated with each other. Growth temperatures scarcely affected these relationships. These results suggest that the photochemistry of PSII and PSI is coordinately regulated primarily depending on the amount of total leaf-N. When excess light energy occurs in low N-acclimated plants, oxidation of the reaction center chlorophyll of PSI is thought to be stimulated to protect PSI from excess light energy. It is also suggested that PSII and PSI normally operate at high temperature used in the present study. In addition, as the relationships between Y(II) and Y(ND) were found to be almost identical to those observed in osmotically stressed rice plants, common regulation is thought to be operative when excess light energy occurs due to different causes.

  15. Physiological Roles of Flavodiiron Proteins and Photorespiration in the Liverwort Marchantia polymorpha. International-journal

    Ginga Shimakawa, Hitomi Hanawa, Shinya Wada, Guy T Hanke, Yusuke Matsuda, Chikahiro Miyake

    Frontiers in plant science　12　668805-668805　2021

    DOI： 10.3389/fpls.2021.668805 　

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    Against the potential risk in oxygenic photosynthesis, that is, the generation of reactive oxygen species, photosynthetic electron transport needs to be regulated in response to environmental fluctuations. One of the most important regulations is keeping the reaction center chlorophyll (P700) of photosystem I in its oxidized form in excess light conditions. The oxidation of P700 is supported by dissipating excess electrons safely to O2, and we previously found that the molecular mechanism of the alternative electron sink is changed from flavodiiron proteins (FLV) to photorespiration in the evolutionary history from cyanobacteria to plants. However, the overall picture of the regulation of photosynthetic electron transport is still not clear in bryophytes, the evolutionary intermediates. Here, we investigated the physiological roles of FLV and photorespiration for P700 oxidation in the liverwort Marchantia polymorpha by using the mutants deficient in FLV (flv1) at different O2 partial pressures. The effective quantum yield of photosystem II significantly decreased at 2kPa O2 in flv1, indicating that photorespiration functions as the electron sink. Nevertheless, it was clear from the phenotype of flv1 that FLV was dominant for P700 oxidation in M. polymorpha. These data suggested that photorespiration has yet not replaced FLV in functioning for P700 oxidation in the basal land plant probably because of the lower contribution to lumen acidification, compared with FLV, as reflected in the results of electrochromic shift analysis.

  16. Intrinsic Fluctuations in Transpiration Induce Photorespiration to Oxidize P700 in Photosystem I International-journal

    Riu Furutani, Amane Makino, Yuij Suzuki, Shinya Wada, Ginga Shimakawa, Chikahiro Miyake

    Plants　9　(12)　1761-1761　2020/12/12

    Publisher: MDPI AG

    DOI： 10.3390/plants9121761 　

    eISSN： 2223-7747

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    Upon exposure to environmental stress, the primary electron donor in photosystem I (PSI), P700, is oxidized to suppress the production of reactive oxygen species that could oxidatively inactivate the function of PSI. The illumination of rice leaves with actinic light induces intrinsic fluctuations in the opening and closing of stomata, causing the net CO2 assimilation rate to fluctuate. We examined the effects of these intrinsic fluctuations on electron transport reactions. Under atmospheric O2 conditions (21 kPa), the effective quantum yield of photosystem II (PSII) (Y(II)) remained relatively high while the net CO2 assimilation rate fluctuated, which indicates the function of alternative electron flow. By contrast, under low O2 conditions (2 kPa), Y(II) fluctuated. These results suggest that photorespiration primarily drove the alternative electron flow. Photorespiration maintained the oxidation level of ferredoxin (Fd) throughout the fluctuation of the net CO2 assimilation rate. Moreover, the relative activity of photorespiration was correlated with both the oxidation level of P700 and the magnitude of the proton gradient across the thylakoid membrane in 21 kPa O2 conditions. These results show that photorespiration oxidized P700 by stimulating the proton gradient formation when CO2 assimilation was suppressed by stomatal closure.

  17. Overproduction of Chloroplast Glyceraldehyde-3-Phosphate Dehydrogenase Improves Photosynthesis Slightly under Elevated [CO2] Conditions in Rice

    Yuji Suzuki, Keiki Ishiyama, Misaki Sugawara, Yuka Suzuki, Eri Kondo, Yuki Takegahara-Tamakawa, Dong-Kyung Yoon, Mao Suganami, Shinya Wada, Chikahiro Miyake, Amane Makino

    Plant and Cell Physiology　62　(1)　156-165　2020/12/08

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/pcp/pcaa149 　

    ISSN： 0032-0781

    eISSN： 1471-9053

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    <title>Abstract</title> Chloroplast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) limits the regeneration of ribulose 1,5-bisphosphate (RuBP) in the Calvin-Benson cycle. However, it does not always limit the rate of CO2 assimilation. In the present study, the effects of overproduction of GAPDH on the rate of CO2 assimilation under elevated [CO2] conditions, where the capacity for RuBP regeneration limits photosynthesis, were examined in transgenic rice (Oryza sativa). GAPDH activity was increased to 6.3- to 9.1-fold of the wild-type levels by co-overexpression of the GAPDH genes, GAPA and GAPB. In the transgenic rice plants, the rate of CO2 assimilation under elevated [CO2] conditions increased by approximately 10%, whereas that under normal and low [CO2] conditions was not affected. These results indicate that overproduction of GAPDH is effective in improving photosynthesis under elevated [CO2] conditions, although its magnitude was relatively small. However, biomass production of the transgenic rice plants was not greater than that in wild-type plants under elevated [CO2] conditions, although starch content tended to increase marginally.

  18. 4-1-28 カルビンサイクル酵素グリセルアルデヒド-3-リン酸デヒドロゲナーゼおよびトリオースリン酸イソメラーゼの遺伝子組換えがイネ葉の光合成に及ぼす影響（4-1 植物の多量栄養素 2020年度岡山大会）

    鈴木 雄二, 石山 敬貴, 菅原 水彩季, 鈴木 優佳, 玉川 夕紀, 和田 慎也, 菅波 眞央, 近藤 依里, 三宅 親弘, 牧野 周

    日本土壌肥料学会講演要旨集　66　46-46　2020/09/01

    Publisher: 一般社団法人 日本土壌肥料学会

    DOI： 10.20710/dohikouen.66.0_46_1 　

    ISSN： 0288-5840

    eISSN： 2424-0575

  19. Photorespiration Enhances Acidification of the Thylakoid Lumen, Reduces the Plastoquinone Pool, and Contributes to the Oxidation of P700 at a Lower Partial Pressure of CO2 in Wheat Leaves Peer-reviewed

    Shinya Wada, Yuji Suzuki, Chikahiro Miyake

    Plants　2020/03

    DOI： 10.3390/plants9030319 　

  20. P700 oxidation suppresses the production of reactive oxygen species in photosystem I

    Riu Furutani, Kentaro Ifuku, Yuji Suzuki, Ko Noguchi, Ginga Shimakawa, Shinya Wada, Amane Makino, Takayuki Sohtome, Chikahiro Miyake

    Advances in Botanical Research　151-176　2020

    Publisher: Elsevier

    DOI： 10.1016/bs.abr.2020.08.001 　

    ISSN： 0065-2296

  21. Photorespiration Coupled With CO2 Assimilation Protects Photosystem I From Photoinhibition Under Moderate Poly(Ethylene Glycol)-Induced Osmotic Stress in Rice. International-journal

    Shinya Wada, Chikahiro Miyake, Amane Makino, Yuji Suzuki

    Frontiers in plant science　11　1121-1121　2020

    DOI： 10.3389/fpls.2020.01121 　

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    Photorespiration coupled with CO2 assimilation is thought to act as a defense system against photoinhibition caused by osmotic stress. In the present study, we examined whether such a mechanism is operative for the protection of photosystem I (PSI) in rice (Oryza sativa L.) including transgenic plants with decreased and increased Rubisco content (RBCS-antisense and RBCS-sense plants, respectively). All plants were hydroponically grown and moderate osmotic stress was imposed using hydroponic culture solutions containing poly(ethylene glycol) (PEG) at 16% or 20% (w/v) for 2 d. In wild-type plants, the rates of CO2 assimilation (A) were significantly decreased by the PEG treatment, whereas the photorespiration activity estimated from the rates of electron transport in photosystem II (PSII) and A were not affected. The maximal quantum efficiency of PSII (Fv/Fm) and the maximal activity of PSI (Pm) were also not affected. In RBCS-antisense plants, A and the estimated photorespiration activity were considerably lower than those in wild-type plants in the presence or absence of the PEG treatment. Pm and both Fv/Fm and Pm decreased in the 16% PEG-treated and 20% PEG-treated RBCS-antisense plants, respectively. Thus, the decrease in Rubisco content led to the photoinhibition of PSI and PSII, indicating the importance of photorespiration coupled with CO2 assimilation for the protection of PSI from moderate PEG-induced osmotic stress. It was also shown that PSI was more sensitive to osmotic stress than PSII. In the PEG-treated wild-type and RBCS-antisense plants, osmotic-stress responses of the photosynthetic electron transport reactions upstream of PSI led to the oxidation of P700, which is thought to prevent PSI from over-reduction. Although such a defense system operated, it was not sufficient for the protection of PSI in RBCS-antisense plants. In addition, there were no large differences in the parameters measured between wild-type and RBCS-sense plants, as overproduction of Rubisco did not increase photorespiration activity.

  22. Oxidation of P700 Induces Alternative Electron Flow in Photosystem I in Wheat Leaves. International-journal

    Kanae Kadota, Riu Furutani, Amane Makino, Yuji Suzuki, Shinya Wada, Chikahiro Miyake

    Plants (Basel, Switzerland)　8　(6)　2019/06/05

    DOI： 10.3390/plants8060152 　

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    Oxygen (O2)-evolving photosynthetic organisms oxidize the reaction center chlorophyll, P700, in photosystem I (PSI) to suppress the production of reactive oxygen species. The oxidation of P700 is accompanied by alternative electron flow in PSI (AEF-I), which is not required for photosynthetic linear electron flow (LEF). To characterize AEF-I, we compared the redox reactions of P700 and ferredoxin (Fd) during the induction of carbon dioxide (CO2) assimilation in wheat leaves, using dark-interval relaxation kinetics analysis. Switching on an actinic light (1000 μmol photons m-2 s-1) at ambient CO2 partial pressure of 40 Pa and ambient O2 partial pressure of 21 kPa gradually oxidized P700 (P700+) and enhanced the reduction rate of P700+ (vP700) and oxidation rate of reduced Fd (vFd). The vFd showed a positive linear relationship with an apparent photosynthetic quantum yield of PSII (Y[II]) originating at point zero; the redox turnover of Fd is regulated by LEF via CO2 assimilation and photorespiration. The vP700 also showed a positive linear relationship with Y(II), but the intercept was positive, not zero. That is, the electron flux in PSI included the electron flux in AEF-I in addition to that in LEF. This indicates that the oxidation of P700 induces AEF-I. We propose a possible mechanism underlying AEF-I and its physiological role in the mitigation of oxidative damage.

  23. Responses of the Photosynthetic Electron Transport Reactions Stimulate the Oxidation of the Reaction Center Chlorophyll of Photosystem I, P700, under Drought and High Temperatures in Rice Peer-reviewed

    Shinya Wada

    International Journal of Molecular Sciences　20　(9)　2068-2068　2019/04/26

    Publisher: MDPI AG

    DOI： 10.3390/ijms20092068 　

    ISSN： 1422-0067

    eISSN： 1422-0067

    More details Close

    It is of interest how photosynthetic electron transport (PET) reactions respond to excess light energy caused by the combination of drought stress and high temperatures. Since such information is scarcely available for photosystem I (PSI), this question was explored in rice (Oryza sativa L.) plants subjected to drought stress, using culture solutions that contain poly(ethylene glycol) at different concentrations under two day/night temperature regimes. At 27/22 °C (day/night), drought stress led to the oxidation of the reaction center of the chlorophyll of PSI (P700), and also led to decreases in the quantum efficiencies of photosystem II (PSII) and PSI, and a reduction of the primary quinone electron acceptor of PSI. Such drought stress responses were wholly stimulated at 35/30 °C. These parameters were strongly correlated with each other and were minimally affected by temperature. These results indicate that the drought stress responses of the respective PET reactions are closely associated with each other in the oxidization of P700 and that such responses are stimulated at high temperatures. The underlying mechanisms of these phenomena were discussed. While P700 oxidation is thought to suppress reactive oxygen species (ROS) production, PSI photoinhibition was observed under severe stress conditions, implying that P700 oxidation is not sufficient for the protection of PSI under drought stress.

  24. Effects of co-overproduction of sedoheptulose-1,7-bisphosphatase and Rubisco on photosynthesis in rice Peer-reviewed

    Suzuki Yuji, Wada Shinya, Kondo Eri, Yamori Wataru, Makino Amane

    SOIL SCIENCE AND PLANT NUTRITION　65　(1)　36-40　2019/01/02

    DOI： 10.1080/00380768.2018.1530053 　

    ISSN： 0038-0768

    eISSN： 1747-0765

  25. Effects of genetic manipulation of the activity of photorespiration on the redox state of photosystem I and its robustness against excess light stress under CO2-limited conditions in rice Peer-reviewed

    Photosynthesis Research　2018/09

    DOI： 10.1007/s11120-018-0515-y 　

    ISSN： 1573-5079

  26. Flavodiiron protein substitutes for cyclic electron flow without competing CO2 assimilation in rice Peer-reviewed

    Shinya Wada, Hiroshi Yamamoto, Yuji Suzuki, Wataru Yamori, Toshiharu Shikanai, Amane Makino

    Plant Physiology　176　(2)　1509-1518　2018/02/01

    Publisher: American Society of Plant Biologists

    DOI： 10.1104/pp.17.01335 　

    ISSN： 1532-2548 0032-0889

  27. Flavodiiron Protein Substitutes for Cyclic Electron Flow without Competing CO2 Assimilation in Rice Peer-reviewed

    Plant Physiology　2018/02

    DOI： 10.1104/pp.17.01335 　

    ISSN： 1532-2548

  28. Vacuolar Protein Degradation via Autophagy Provides Substrates to Amino Acid Catabolic Pathways as an Adaptive Response to Sugar Starvation in Arabidopsis thaliana Peer-reviewed

    Plant and Cell Physiology　2018/01/30

    DOI： 10.1093/pcp/pcy005 　

    ISSN： 1471-9053

  29. P4-1-12 ヒメツリガネゴケflavodiiron protein（PpFLV）を導入したイネの成長と光合成特性の解析（ポスター，4-1 植物の多量栄養素，2016年度佐賀大会）

    和田 慎也, 山本 宏, 鹿内 利治, 牧野 周

    日本土壌肥料学会講演要旨集　62　54-54　2016

    Publisher: 一般社団法人 日本土壌肥料学会

    DOI： 10.20710/dohikouen.62.0_54_3 　

  30. 4-1-15 異なる光環境におけるイネの栄養成長とオートファジー（4-1 植物の多量栄養素，2016年度佐賀大会）

    和田 慎也, 山内 雄太, 石田 宏幸, 牧野 周

    日本土壌肥料学会講演要旨集　62　47-47　2016

    Publisher: 一般社団法人 日本土壌肥料学会

    DOI： 10.20710/dohikouen.62.0_47_3 　

  31. 生物情報科学・細胞生物学的手法から見えてきた植物栄養応答 2.イネの窒素リサイクルとオートファジー Invited Peer-reviewed

    和田慎也, 泉正範

    日本土壌肥料学雑誌　87　(5)　388-393　2016

    Publisher: Japanese Society of Soil Science and Plant Nutrition

    DOI： 10.20710/dojo.87.5_388 　

  32. Autophagy Supports Biomass Production and Nitrogen Use Efficiency at the Vegetative Stage in Rice Peer-reviewed

    Shinya Wada, Yasukazu Hayashida, Masanori Izumi, Takamitsu Kurusu, Shigeru Hanamata, Keiichi Kanno, Soichi Kojima, Tomoyuki Yamaya, Kazuyuki Kuchitsu, Amane Makino, Hiroyuki Ishida

    Plant Physiology　168　(1)　60-73　2015/03

    Publisher: American Society of Plant Biologists ({ASPB})

    DOI： 10.1104/pp.15.00242 　

    ISSN： 0032-0889

  33. Establishment of Monitoring Methods for Autophagy in Rice Reveals Autophagic Recycling of Chloroplasts and Root Plastids during Energy Limitation Peer-reviewed

    Masanori Izumi, Jun Hidema, Shinya Wada, Eri Kondo, Takamitsu Kurusu, Kazuyuki Kuchitsu, Amane Makino, Hiroyuki Ishida

    Plant Physiology　167　(4)　1307-1320　2015/02

    Publisher: American Society of Plant Biologists ({ASPB})

    DOI： 10.1104/pp.114.254078 　

    ISSN： 0032-0889

  34. 4-2-6 シロイヌナズナにおけるオートファジーが亜鉛欠乏時に果たす役割(4-2 植物の微量栄養素,2015年度京都大会) Peer-reviewed

    江口 雅丈, 吉本 光希, 木村 和彦, 泉 正範, 和田 慎也, 牧野 周, 石田 宏幸

    日本土壌肥料学会講演要旨集　61　(0)　66-66　2015

    Publisher: 一般社団法人 日本土壌肥料学会

    DOI： 10.20710/dohikouen.61.0_66_3 　

    ISSN： 0288-5840

  35. Roles of autophagy in chloroplast recycling Peer-reviewed

    Hiroyuki Ishida, Masanori Izumi, Shinya Wada, Amane Makino

    BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS　1837　(4)　512-521　2014/04

    DOI： 10.1016/j.bbabio.2013.11.009 　

    ISSN： 0005-2728

    eISSN： 0006-3002

  36. OsATG7 is required for autophagy-dependent lipid metabolism in rice postmeiotic anther development Peer-reviewed

    Takamitsu Kurusu, Tomoko Koyano, Shigeru Hanamata, Takahiko Kubo, Yuhei Noguchi, Chikako Yagi, Noriko Nagata, Takashi Yamamoto, Takayuki Ohnishi, Yozo Okazaki, Nobutaka Kitahata, Daichi Ando, Masaya Ishikawa, Shinya Wada, Akio Miyao, Hirohiko Hirochika, Hiroaki Shimada, Amane Makino, Kazuki Saito, Hiroyuki Ishida, Tetsu Kinoshita, Nori Kurata, Kazuyuki Kuchitsu

    Autophagy　10　(5)　878-888　2014/03

    Publisher: Informa {UK} Limited

    DOI： 10.4161/auto.28279 　

    ISSN： 1554-8627

  37. Evidence for contribution of autophagy to Rubisco degradation during leaf senescence inArabidopsis thaliana Peer-reviewed

    YUKI ONO, SHINYA WADA, MASANORI IZUMI, AMANE MAKINO, HIROYUKI ISHIDA

    Plant, Cell & Environment　36　(6)　1147-1159　2013/01/07

    Publisher: Wiley-Blackwell

    DOI： 10.1111/pce.12049 　

    ISSN： 0140-7791

  38. PGR5-Dependent Cyclic Electron Transport Around PSI Contributes to the Redox Homeostasis in Chloroplasts Rather Than CO2 Fixation and Biomass Production in Rice Peer-reviewed

    Plant and Cell Physiology　2012/12

    DOI： 10.1093/pcp/pcs153 　

    ISSN： 0032-0781

  39. A possible involvement of autophagy in amyloplast degradation in columella cells during hydrotropic response of Arabidopsis roots Peer-reviewed

    Mayumi Nakayama, Yasuko Kaneko, Yutaka Miyazawa, Nobuharu Fujii, Nahoko Higashitani, Shinya Wada, Hiroyuki Ishida, Kohki Yoshimoto, Ken Shirasu, Kenji Yamada, Mikio Nishimura, Hideyuki Takahashi

    Planta　236　(4)　999-1012　2012/04

    Publisher: Springer Nature

    DOI： 10.1007/s00425-012-1655-5 　

    ISSN： 0032-0935

  40. The Autophagic Degradation of Chloroplasts via Rubisco-Containing Bodies Is Specifically Linked to Leaf Carbon Status But Not Nitrogen Status in Arabidopsis Peer-reviewed

    Masanori Izumi, Shinya Wada, Amane Makino, Hiroyuki Ishida

    PLANT PHYSIOLOGY　154　(3)　1196-1209　2010/11

    DOI： 10.1104/pp.110.158519 　

    ISSN： 0032-0889

  41. The Autophagic Degradation of Chloroplasts via Rubisco-Containing Bodies Is Specifically Linked to Leaf Carbon Status But Not Nitrogen Status in Arabidopsis Peer-reviewed

    Plant Physiology　2010/11

    DOI： 10.1104/pp.110.158519 　

    ISSN： 1532-2548

  42. The chloroplast degradation in two different pathways in individually darkened leaves of Arabidopsis by autophagy

    Wada S, Ishida H, Yoshimoto K, Ohsumi Y, Makino A

    Autophagy　2009/09

  43. The role of plant autophagy in nutrient starvation and aging Peer-reviewed

    Yoshimoto Kohki, Ishida Hiroyuki, Wada Shinya, Ohsumi Yoshinori, Shirasu Ken

    AUTOPHAGY　5　(6)　904　2009/08/16

    ISSN： 1554-8627

  44. Autophagy of whole and partial chloroplasts in individually darkened leaves: A unique system in plants? Peer-reviewed

    Hiroyuki Ishida, Shinya Wada

    Autophagy　5　(5)　736-737　2009/07

    Publisher: Informa {UK} Limited

    DOI： 10.4161/auto.5.5.8568 　

    ISSN： 1554-8627

  45. Chloroplasts autophagy during senescence of individually darkened leaves Peer-reviewed

    Shinya Wada, Hiroyuki Ishida

    Plant Signaling & Behavior　4　(6)　565-567　2009/06

    Publisher: Informa {UK} Limited

    DOI： 10.4161/psb.4.6.8877 　

    ISSN： 1559-2324

  46. Autophagy Plays a Role in Chloroplast Degradation during Senescence in Individually Darkened Leaves Peer-reviewed

    Shinya Wada, Hiroyuki Ishida, Masanori Izumi, Kohki Yoshimoto, Yoshinori Ohsumi, Tadahiko Mae, Amane Makino

    PLANT PHYSIOLOGY　149　(2)　885-893　2009/02

    DOI： 10.1104/pp.108.130013 　

    ISSN： 0032-0889

    eISSN： 1532-2548

  47. Autophagy Plays a Role in Chloroplast Degradation during Senescence in Individually Darkened Leaves Peer-reviewed

    Plant Physiology　2009/02

    DOI： 10.1104/pp.108.130013 　

    ISSN： 1532-2548

  48. Autophagy of chloroplast proteins Invited

    Ishida H, Wada S

    Photosynthesis research (Japanese)　53　89-94　2008/12

Show all ︎Show first 5

Misc. 14

  1. イネにおけるP700吸光パラメーターによる水ストレス診断

    和田慎也, 和田慎也, 鈴木雄二, 鈴木雄二, 高木大輔, 高木大輔, 三宅親弘, 三宅親弘, 牧野周, 牧野周

    日本土壌肥料学会講演要旨集　64　56　2018/08/29

    ISSN： 0288-5840

  2. Rubiscoの改変によるC3型植物の光合成機能改良の試み

    鈴木雄二, 和田慎也, 牧野 周

    光合成研究　27　(2)　97-102　2017/08

    Publisher: 日本光合成研究会

    ISSN： 1884-2852

  3. P4-1-12 イネの栄養成長と老化葉の窒素リサイクルにおけるオートファジーの役割の解析(ポスター,4-1 植物の多量栄養素,2015年度京都大会)

    和田 慎也, 林田 泰和, 泉 正範, 来須 孝光, 花俣 繁, 朽津 和幸, 牧野 周, 石田 宏幸

    日本土壌肥料学会講演要旨集　(61)　62-62　2015/09/09

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  4. 4-1-5 イネの発芽過程におけるオートファジーの役割(4-1 植物の多量栄養素,2015年度京都大会)

    和田 慎也, 中村 萌, 石田 宏幸, 牧野 周

    日本土壌肥料学会講演要旨集　(61)　49-49　2015/09/09

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  5. 4-1-5 異なる窒素栄養条件下においてオートファジーの欠損がイネの窒素利用と成長に及ぼす影響の解析(4-1 植物の多量栄養素,2014年度東京大会)

    和田 慎也, 横浜 諒, 石田 宏幸, 牧野 周

    日本土壌肥料学会講演要旨集　(60)　48-48　2014/09/09

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  6. 4-1-8 イネ循環的電子伝達変異体の光合成特性とRubisco活性化制御への影響の解析(4-1 植物の多量栄養素,2014年度東京大会)

    和田 慎也, 山本 宏, 鹿内 利治, 牧野 周

    日本土壌肥料学会講演要旨集　(60)　49-49　2014/09/09

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  7. 8 オートファジー関連遺伝子ATG7の欠損がイネのバイオマス及び窒素利用に及ぼす影響の解析(東北支部講演会,2012年度各支部会)

    和田 慎也, 林田 泰和, 来須 孝光, 朽津 和幸, 牧野 周, 石田 宏幸

    日本土壌肥料学会講演要旨集　(59)　253-253　2013/09/11

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  8. 4-1-16 イネオートファジー欠損変異体Osatg7の生理解析 : (その2)葉の老化過程における窒素転流への影響について(4-1 植物の多量栄養素)

    林田 泰和, 和田 慎也, 来須 孝光, 朽津 和幸, 牧野 周, 石田 宏幸

    日本土壌肥料学会講演要旨集　(59)　59-59　2013/09/11

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  9. 4-1-15 イネオートファジー欠損変異体Osatg7の生理解析 : (その1)栄養成長期における個体生育について(4-1 植物の多量栄養素)

    和田 慎也, 林田 泰和, 来須 孝光, 朽津 和幸, 牧野 周, 石田 宏幸

    日本土壌肥料学会講演要旨集　(59)　58-58　2013/09/11

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  10. 9-4 葉の老化時のRubisco分解におけるオートファジーの貢献度の評価(9.植物の多量栄養素,2012年度鳥取大会)

    小野 佑樹, 和田 慎也, 泉 正範, 牧野 周, 石田 宏幸

    日本土壌肥料学会講演要旨集　(58)　54-54　2012/09/04

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  11. 9-21 シロイヌナズナ個別暗処理葉におけるオートファジー葉緑体分解機構(9.植物の多量栄養素,2010年度北海道大会)

    和田 慎也, 石田 宏幸, 吉本 光希, 大隅 良典, 牧野 周

    日本土壌肥料学会講演要旨集　(56)　60-60　2010/09/07

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  12. 10-15 シロイヌナズナの個葉・個体暗処理による老化誘導と、オートファジーによる葉緑体分解(10.植物の代謝,2008年度愛知大会)

    和田 慎也, 石田 宏幸, 吉本 光希, 大隅 良典, 前 忠彦, 牧野 周

    日本土壌肥料学会講演要旨集　(54)　100-100　2008/09/09

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

  13. Changes in the amount of Rubisco, leaf nitrogen and chlorophyll, and chloroplast number in the senescing leaf of wild-type Arabidopsis thaliana and autophagy defected mutant, Atatg4a4b-I.

    Shinya Wada, Hiroyuki Ishida, Kohki Yoshimoto, Yoshinori Ohsumi, Amane Makino, Tadahiko Mae

    PLANT AND CELL PHYSIOLOGY　48　S196-S196　2007

    ISSN： 0032-0781

  14. 10-10 Rubisco 大サブユニットを44kDに分解する葉緑体プロテアーゼの精製とその特性解析(10. 植物の代謝, 2006年度秋田大会講演要旨)

    和田 慎也, 石田 宏幸, 牧野 周, 前 忠彦

    日本土壌肥料学会講演要旨集　(52)　87-87　2006/09/05

    Publisher: 一般社団法人日本土壌肥料学会

    ISSN： 0288-5840

Show all ︎Show first 5

Research Projects 3

  1. 生育表現型の回復した光合成因子欠損株のゲノム変異とその光合成機構の解析

    和田 慎也

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(C)

    Institution: 神戸大学

    2020/04/01 - 2023/03/31

    More details Close

    本研究では生育表現型の異なる2つのPGR5欠損シロイヌナズナ株(pgr5-1, hope1)の生育差を遺伝学的に解明し、植物の光ストレス耐性に関わる知見を得ること、またその情報を光合成能力の向上へと応用することを目指したものである。 本研究では当初、新規に単離されたhope1株にPGR5欠損変異による影響を相補する第2変異の存在が想定されたが、前年度の解析の結果、pgr5-1株に生育表現型の原因となっていた第2変異(ptp1変異)が見出された。今年度(2年目)は、そのptp1変異の解析を中心に解析を進めた。また、ptp1変異はpgr5変異との二重変異により生育をさらに抑制する変異であることが明らかとなり、既存のpgr5-1株から報告されていたPGR5欠損による光合成への影響も再検証する必要が出てきたため、PGR5とPTP1それぞれ単独の欠損変異による光合成および生育への影響、およびそれらの二重変異による影響を解析した。解析の結果、ptp1の単独変異ではわずかに葉のクロロフィル含量が低下するものの、光合成および生育への影響はほとんど見られず、強光ストレスへの感受性も野生体と違いは見られなかった。しかし、pgr5との二重変異により光ストレスに対する感受性が増加し、CO2固定速度および生育が大きく低下する表現型が見られた。とりわけ、二重変異株は光化学系I(PSI)への光酸化傷害が顕著に生じており、これがCO2固定速度等の光合成能力の低下の原因であることが考えられた。以上の結果より、PTP1は直接電子伝達系に影響する因子ではないものの、その機能としてPSIの光酸化傷害を緩和することが推察された。

  2. Molecular basis of recycling and quality control of chloroplasts by selective autophagy

    Ishida Hiroyuki, IZUMI Masanori, WADA Shinya, EGUCHI Masatake, HIROTA Takaaki, YOKOHAMA Ryo, NISHIMURA Tsubasa, NAKAMURA Sakuya, ISHIDA Hiromi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: Tohoku University

    2015/04/01 - 2019/03/31

    More details Close

    We aimed to reveal molecular mechanisms of selective autophagy of chloroplasts and obtained following results. (1) We revealed roles of known ATG8-interacting proteins, NBR1, ATG11, and ATI1/2 on the RCB (Rubisco-containing body) pathway and chlorophagy (whole-chloroplast autophagy). (2) We isolated novel mutants having abnormality on the RCB pathway. (3) We searched novel autophagy receptors which may act for chloroplast by co-immunoprecipitation and LC-MS/MS analysis.

  3. イネの体内窒素分配とオートファジーの役割の解明

    和田 慎也

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 若手研究(B)

    Institution: 東北大学

    2016/04/01 - 2018/03/31