start-ver=1.4 cd-journal=joma no-vol=123 cd-vols= no-issue=17 article-no= start-page=e2536813123 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2026 dt-pub=20260422 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A magnesium efflux transporter required for seed development and eating quality in rice en-subtitle= kn-subtitle= en-abstract= kn-abstract=As a staple food for half the worldfs population, rice is an important dietary source of magnesium (Mg), an essential mineral for human health. Enhanced Mg accumulation in rice grains has also been linked to eating quality. However, the mechanisms underlying Mg transport to the grains remains poorly understood. Here, we report that OsMGR2, a member belonging to Magnesium Release (MGR) family, is required for Mg accumulation in rice grains. OsMGR2 encodes a plasma membrane-localized transporter that mediates Mg efflux. OsMGR2 is constitutively and highly expressed in the stele tissues of roots, the phloem region of both enlarged and diffused vascular bundles in nodes, and the ovular vascular trace of caryopses. Knockout of this gene results in decreased root-to-shoot translocation and altered distribution of Mg to different organs; less Mg is allocated to the second newest leaf with high Mg requirement for active photosynthesis. The osmgr2 mutants exhibit decreased Mg accumulation in the grain, which are smaller, lighter, and shriveled, but show increased accumulation in the husk. The eating quality of the mutant grains is significantly decreased compared with the wild-type rice. These results indicate that OsMGR2 plays multiple roles within the rice; facilitating the root-to-shoot Mg translocation, mediating phloem-to-xylem Mg transfer at nodes for preferential distribution to the most active leaf, and exporting Mg from maternal vascular tissues of the caryopsis to the grains, processes essential for grain development and eating quality in rice. en-copyright= kn-copyright= en-aut-name=HuangSheng en-aut-sei=Huang en-aut-mei=Sheng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HoriKiyosumi en-aut-sei=Hori en-aut-mei=Kiyosumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YoshiokaYuma en-aut-sei=Yoshioka en-aut-mei=Yuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=NingMin en-aut-sei=Ning en-aut-mei=Min kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=NagayaYu en-aut-sei=Nagaya en-aut-mei=Yu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=MiyajiTakaaki en-aut-sei=Miyaji en-aut-mei=Takaaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=Mitani-UenoNamiki en-aut-sei=Mitani-Ueno en-aut-mei=Namiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=InoueShin-ichiro en-aut-sei=Inoue en-aut-mei=Shin-ichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=KimJune-Sik en-aut-sei=Kim en-aut-mei=June-Sik kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=KashinoMiho en-aut-sei=Kashino en-aut-mei=Miho kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=National Institute of Crop Science, National Agriculture Research Organization kn-affil= affil-num=3 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=5 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=8 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=9 en-affil=Department of Regulatory Biology, Saitama University kn-affil= affil-num=10 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=11 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=12 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=magnesium kn-keyword=magnesium en-keyword=rice kn-keyword=rice en-keyword=transporter kn-keyword=transporter END start-ver=1.4 cd-journal=joma no-vol=120 cd-vols= no-issue=1 article-no= start-page=76 end-page=90 dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240814 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=OsHAK4 functions in retrieving sodium from the phloem at the reproductive stage of rice en-subtitle= kn-subtitle= en-abstract= kn-abstract=Soil salinity significantly limits rice productivity, but it is poorly understood how excess sodium (Na+) is delivered to the grains at the reproductive stage. Here, we functionally characterized OsHAK4, a member of the clade IV HAK/KUP/KT transporter subfamily in rice. OsHAK4 was localized to the plasma membrane and exhibited influx transport activity for Na+, but not for K+. Analysis of organ- and growth stage-dependent expression patterns showed that very low expression levels of OsHAK4 were detected at the vegetative growth stage, but its high expression in uppermost node I, peduncle, and rachis was found at the reproductive stage. Immunostaining indicated OsHAK4 localization in the phloem region of node I, peduncle, and rachis. Knockout of OsHAK4 did not affect the growth and Na+ accumulation at the vegetative stage. However, at the reproductive stage, the hak4 mutants accumulated higher Na+ in the peduncle, rachis, husk, and brown rice compared to the wild-type rice. Element imaging revealed higher Na+ accumulation at the phloem region of the peduncle in the mutants. These results indicate that OsHAK4 plays a crucial role in retrieving Na+ from the phloem in the upper nodes, peduncle, and rachis, thereby preventing Na+ distribution to the grains at the reproductive stage of rice. en-copyright= kn-copyright= en-aut-name=CheJing en-aut-sei=Che en-aut-mei=Jing kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=WangShao Fei en-aut-sei=Wang en-aut-mei=Shao Fei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=XiaYue en-aut-sei=Xia en-aut-mei=Yue kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YangShun Ying en-aut-sei=Yang en-aut-mei=Shun Ying kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=SuYan Hua en-aut-sei=Su en-aut-mei=Yan Hua kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ShenRen Fang en-aut-sei=Shen en-aut-mei=Ren Fang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences kn-affil= affil-num=4 en-affil=Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences kn-affil= affil-num=5 en-affil=Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences kn-affil= affil-num=6 en-affil=Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences kn-affil= affil-num=7 en-affil=Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences kn-affil= affil-num=8 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=rice kn-keyword=rice en-keyword=Oryza sativa kn-keyword=Oryza sativa en-keyword=salinity kn-keyword=salinity en-keyword=HAK transporter kn-keyword=HAK transporter en-keyword=phloem unloading kn-keyword=phloem unloading en-keyword=node kn-keyword=node END start-ver=1.4 cd-journal=joma no-vol=177 cd-vols= no-issue=4 article-no= start-page=e70398 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=202507 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Comparative Transcriptome Reveals ART1-Dependent Regulatory Pathways for Fe Toxicity Response in Rice Roots en-subtitle= kn-subtitle= en-abstract= kn-abstract=Iron (Fe) is an essential element for plants, but an excess supply can have detrimental effects. Fe toxicity induces complex physiological and genetic responses, and due to this complexity, the knowledge of transcriptional regulatory mechanisms under Fe toxicity is very limited. Previous studies suggested that plant responses to excess Fe involve oxidative stress caused by reactive oxygen species (ROS), which itself causes transcriptional changes. We hypothesized that dissecting these complex responses could lead to the identification of a novel factor and conducted a comparative transcriptome analysis using roots of rice plants exposed to nutrient solutions containing 1 or 5?mM of hydrogen peroxide (a major form of ROS) or 300?mg?L?1 of Fe (as FeSO4). Genes induced by hydrogen peroxide overlapped with 62%, 49%, and 30% of Fe toxicity-upregulated genes at 3?h, 1?day, and 3?days following treatment initiation. Subsequent gene co-expression analyses classified genes into 21 groups with varying responsiveness to ROS and Fe toxicity. Genes in group 15 were specifically upregulated by Fe toxicity and overlapped significantly with aluminum (Al)-inducible genes and target genes of the Zn-finger transcription factor, ART1, which regulates Al response in rice roots. Additional experiments using the art1 knock-out mutant demonstrated that ART1 is crucial for upregulating genes such as STAR2 and FRDL4 in response to Fe toxicity. This study reveals the contribution of ART1-dependent regulatory pathways in rice roots under Fe toxicity. en-copyright= kn-copyright= en-aut-name=UedaYoshiaki en-aut-sei=Ueda en-aut-mei=Yoshiaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=WissuwaMatthias en-aut-sei=Wissuwa en-aut-mei=Matthias kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Crop, Livestock and Environment Division, Japan International Research Center for Agricultural Sciences kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Crop, Livestock and Environment Division, Japan International Research Center for Agricultural Sciences kn-affil= en-keyword=ART1 kn-keyword=ART1 en-keyword=gene co-expression analysis kn-keyword=gene co-expression analysis en-keyword=iron toxicity kn-keyword=iron toxicity en-keyword=reactive oxygen species kn-keyword=reactive oxygen species en-keyword=rice kn-keyword=rice END start-ver=1.4 cd-journal=joma no-vol=16 cd-vols= no-issue=1 article-no= start-page=9916 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20251111 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A node-localized efflux transporter for loading iron to developing tissues in rice en-subtitle= kn-subtitle= en-abstract= kn-abstract=Iron (Fe) is an essential micronutrient for plant growth and development. It plays crucial roles in various organs and tissues of plants, but the molecular mechanisms governing its distribution to the above-ground parts after root uptake remain unclear. In this study, we identify OsIET1 (Oryza sativa Iron Efflux Transporter 1), a rice gene highly expressed in the nodes. OsIET1 encodes a plasma membrane-localized protein, which shows efflux transport activity for ferrous iron. It is predominantly expressed in the xylem regions of diffuse vascular bundles, and its expression is upregulated under high Fe conditions. Disruption of OsIET1 impairs Fe allocation, reducing Fe transport to developing tissues (young leaves and grains), while increasing accumulation in nodes and older leaves. This misdistribution causes chlorosis in young leaves and decreases grain yield, especially under Fe-deficient conditions. Furthermore, we detect excessive Fe deposition around the xylem of diffuse vascular bundles in the nodes. Given the pivotal role of nodes in mineral distribution, our results indicate that OsIET1 mediates inter-vascular Fe transfer by facilitating Fe loading into the xylem of diffuse vascular bundles. This process ensures preferential Fe delivery to developing tissues, thereby promoting optimal plant growth and productivity. en-copyright= kn-copyright= en-aut-name=CheJing en-aut-sei=Che en-aut-mei=Jing kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HuangSheng en-aut-sei=Huang en-aut-mei=Sheng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=QuYuting en-aut-sei=Qu en-aut-mei=Yuting kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YoshiokaYuma en-aut-sei=Yoshioka en-aut-mei=Yuma kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TomitaChiyuri en-aut-sei=Tomita en-aut-mei=Chiyuri kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MiyajiTakaaki en-aut-sei=Miyaji en-aut-mei=Takaaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=LiuZhenyang en-aut-sei=Liu en-aut-mei=Zhenyang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=ShenRenfang en-aut-sei=Shen en-aut-mei=Renfang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences kn-affil= affil-num=4 en-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University kn-affil= affil-num=7 en-affil=State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences kn-affil= affil-num=8 en-affil=State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences kn-affil= affil-num=9 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=10 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=118 cd-vols= no-issue=10 article-no= start-page=146 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250901 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Duganella hordei sp. nov., Duganella caerulea sp. nov., and Duganella rhizosphaerae sp. nov., isolated from barley rhizosphere en-subtitle= kn-subtitle= en-abstract= kn-abstract=Duganella sp. strains R1T, R57T, and R64T, isolated from barley roots in Japan, are Gram-stain-negative, motile, rod-shaped bacteria. Duganella species abundantly colonized barley roots. Strains R1T, R57T, and R64T were capable of growth at 4 ‹C, suggesting adaptation to colonize winter barley roots. Strains R57T and R64T formed purple colonies, indicating violacein production, while strain R1T did not. Based on 16S rRNA gene sequence similarities, strains R1T, R57T, and R64T were most closely related to D. violaceipulchra HSC-15S17T (99.10%), D. vulcania FT81WT (99.45%), and D. violaceipulchra HSC-15S17T (99.86%), respectively. Their genome sizes ranged from 7.05 to 7.38 Mbp, and their genomic G+C contents were 64.2?64.7%. The average nucleotide identity and digital DNA?DNA hybridization values between R1T and D. violaceipulchra HSC-15S17T, R57T and D. vulcania FT81WT, R64T and D. violaceipulchra HSC-15S17T were 86.0% and 33.2%, 95.7% and 67.9%, and 92.7% and 52.6%, respectively. Their fatty acids were predominantly composed of C16:0, C17:0 cyclo, and summed feature 3 (C16:1 ƒÖ7c and/or C16:1 ƒÖ6c). Based on their distinct genetic and phenotypic characteristics, and supported by chemotaxonomic analyses, we propose that strains R1T, R57T, and R64T represent novel species within the Duganella genus, for which the names Duganella hordei (type strain R1T?=?NBRC 115982 T?=?DSM 115069 T), Duganella caerulea (type strain R57T?=?NBRC 115983 T?=?DSM 115070 T), and Duganella rhizosphaerae (type strain R64T?=?NBRC 115984 T?=?DSM 115071 T) are proposed. en-copyright= kn-copyright= en-aut-name=KishiroKatsumoto en-aut-sei=Kishiro en-aut-mei=Katsumoto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SahinNurettin en-aut-sei=Sahin en-aut-mei=Nurettin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SaishoDaisuke en-aut-sei=Saisho en-aut-mei=Daisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YamashitaJun en-aut-sei=Yamashita en-aut-mei=Jun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MondenYuki en-aut-sei=Monden en-aut-mei=Yuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=NakagawaTomoyuki en-aut-sei=Nakagawa en-aut-mei=Tomoyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=MochidaKeiichi en-aut-sei=Mochida en-aut-mei=Keiichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=TaniAkio en-aut-sei=Tani en-aut-mei=Akio kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Egitim Fakultesi, Mugla Sitki Kocman University kn-affil= affil-num=3 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=4 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=5 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Faculty of Applied Biological Sciences, Gifu University kn-affil= affil-num=8 en-affil=RIKEN Center for Sustainable Resource Science kn-affil= affil-num=9 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=Barley kn-keyword=Barley en-keyword=Duganella kn-keyword=Duganella en-keyword=Novel species kn-keyword=Novel species en-keyword=Rhizosphere kn-keyword=Rhizosphere END start-ver=1.4 cd-journal=joma no-vol=122 cd-vols= no-issue=32 article-no= start-page=e2501933122 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250805 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural insights into a citrate transporter that mediates aluminum tolerance in barley en-subtitle= kn-subtitle= en-abstract= kn-abstract=HvAACT1 is a major aluminum (Al)-tolerance gene in barley, encoding a citrate transporter that belongs to the multidrug and toxic compound extrusion (MATE) family. This transporter facilitates citrate secretion from the roots, thereby detoxifying external Al ions?a major constraint of crop production on acidic soils. In this study, we present the outward-facing crystal structure of HvAACT1, providing insights into a citrate transport mechanism. The putative citrate binding site consists of three basic residues?K126 in transmembrane helix 2 (TM2), R358 in TM7, and R535 in TM12?creating substantial positive charges in the C-lobe cavity. Proton coupling for substrate transport may involve two pairs of aspartate residues in the N-lobe cavity, one of which corresponds to the essential Asp pair found in prokaryotic H+-coupled MATE transporters belonging to the DinF subfamily. Structural coupling between proton uptake in the N-lobe and citrate extrusion in the C-lobe can be enabled by an extensive, unique hydrogen-bonding network at the extracellular half of the N-lobe. Mutation-based functional analysis, structural comparisons, molecular dynamics simulation, and phylogenic analysis suggest an evolutionary link between citrate MATE transporters and the DinF MATE subfamily. Our findings provide a solid structural basis for citrate transport by HvAACT1 in barley and contribute to a broader understanding of citrate transporter structures in other plant species. en-copyright= kn-copyright= en-aut-name=Nguyen ThaoTran en-aut-sei=Nguyen Thao en-aut-mei=Tran kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=Mitani-UenoNamiki en-aut-sei=Mitani-Ueno en-aut-mei=Namiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=UranoRyo en-aut-sei=Urano en-aut-mei=Ryo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SaitohYasunori en-aut-sei=Saitoh en-aut-mei=Yasunori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=WangPeitong en-aut-sei=Wang en-aut-mei=Peitong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=ShinodaWataru en-aut-sei=Shinoda en-aut-mei=Wataru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= affil-num=1 en-affil=Degree Program in Interdisciplinary Sciences, Graduate School of Environmental, Life, Natural Science, and Technology, Okayama University kn-affil= affil-num=2 en-affil=Research Core for Plant Stress Science, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Division of Superconducting and Functional Materials, Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=4 en-affil=Degree Program in Interdisciplinary Sciences, Graduate School of Environmental, Life, Natural Science, and Technology, Okayama University kn-affil= affil-num=5 en-affil=Research Core for Plant Stress Science, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=6 en-affil=Research Core for Plant Stress Science, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=7 en-affil=Degree Program in Interdisciplinary Sciences, Graduate School of Environmental, Life, Natural Science, and Technology, Okayama University kn-affil= affil-num=8 en-affil=Degree Program in Interdisciplinary Sciences, Graduate School of Environmental, Life, Natural Science, and Technology, Okayama University kn-affil= affil-num=9 en-affil=Research Core for Plant Stress Science, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=10 en-affil=Degree Program in Interdisciplinary Sciences, Graduate School of Environmental, Life, Natural Science, and Technology, Okayama University kn-affil= en-keyword=barley kn-keyword=barley en-keyword=aluminum resistance kn-keyword=aluminum resistance en-keyword=membrane protein structure kn-keyword=membrane protein structure en-keyword=citrate transporter kn-keyword=citrate transporter en-keyword=MATE transporter kn-keyword=MATE transporter END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=1 end-page=11 dt-received= dt-revised= dt-accepted= dt-pub-year=2025 dt-pub=20250707 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Dual roles of suberin deposition at the endodermal Casparian strip in manganese uptake of rice en-subtitle= kn-subtitle= en-abstract= kn-abstract=Rice roots are characterized by having two Casparian strips (CSs) at the exodermis and endodermis, where transporters for mineral nutrients are expressed. However, the exact role of the CS in expression of the transporters and subsequent nutrient uptake is poorly understood. Here, we first investigated the role of the CS in manganese (Mn) uptake by using a rice mutant (oscasp1) defective in formation of the endodermal CS. Knockout of OsCASP1 resulted in decreased Mn uptake under limited Mn conditions, but increased Mn uptake at high Mn concentration. Immunostaining revealed that knockout of OsCASP1 did not affect the cell specificity of localization of two transporters (OsNramp5 and OsMTP9) required for Mn uptake, but decreased the protein abundance of these transporters at the endodermis regardless of Mn concentrations tested. Furthermore, we found that overaccumulation of suberin at the endodermis of the mutants suppressed the expression of two transporters; the expression of the two transporters was only observed in the endodermal cells without suberin deposition, but not in the cells with suberin deposition. Taken together, our results indicate that there are two roles for the CS in Mn uptake; maintaining normal expression of the transporters at limited Mn concentration and preventing Mn diffusion to the stele at high Mn concentration. en-copyright= kn-copyright= en-aut-name=FujiiToshiki en-aut-sei=Fujii en-aut-mei=Toshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=Casparian strip kn-keyword=Casparian strip en-keyword=endodermis kn-keyword=endodermis en-keyword=manganese transporter kn-keyword=manganese transporter en-keyword=rice kn-keyword=rice en-keyword=root kn-keyword=root en-keyword=suberin deposition kn-keyword=suberin deposition END start-ver=1.4 cd-journal=joma no-vol=15 cd-vols= no-issue=1 article-no= start-page=10712 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20241227 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Shoot-Silicon-Signal protein to regulate root silicon uptake in rice en-subtitle= kn-subtitle= en-abstract= kn-abstract=Plants accumulate silicon to protect them from biotic and abiotic stresses. Especially in rice (Oryza sativa), a typical Si-accumulator, tremendous Si accumulation is indispensable for healthy growth and productivity. Here, we report a shoot-expressed signaling protein, Shoot-Silicon-Signal (SSS), an exceptional homolog of the flowering hormone gflorigenh differentiated in Poaceae. SSS transcript is only detected in the shoot, whereas the SSS protein is also detected in the root and phloem sap. When Si is supplied from the root, the SSS transcript rapidly decreases, and then the SSS protein disappears. In sss mutants, root Si uptake and expression of Si transporters are decreased to a basal level regardless of the Si supply. The grain yield of the mutants is decreased to 1/3 due to insufficient Si accumulation. Thus, SSS is a key phloem-mobile protein for integrating root Si uptake and shoot Si accumulation underlying the terrestrial adaptation strategy of grasses. en-copyright= kn-copyright= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=Mitani-UenoNamiki en-aut-sei=Mitani-Ueno en-aut-mei=Namiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=FujiiToshiki en-aut-sei=Fujii en-aut-mei=Toshiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ShinyaTomonori en-aut-sei=Shinya en-aut-mei=Tomonori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=ShaoJi Feng en-aut-sei=Shao en-aut-mei=Ji Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=WatanukiShota en-aut-sei=Watanuki en-aut-mei=Shota kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SaitohYasunori en-aut-sei=Saitoh en-aut-mei=Yasunori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=4 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=5 en-affil=State Key Laboratory of Subtropical Silviculture, Zhejiang Agriculture & Forestry University kn-affil= affil-num=6 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Environmental, Life, Natural Science and Technology, Okayama University kn-affil= affil-num=8 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=45 cd-vols= no-issue=11 article-no= start-page=3322 end-page=3337 dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220907 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=FE UPTAKE]INDUCING PEPTIDE1 maintains Fe translocation by controlling Fe deficiency response genes in the vascular tissue of Arabidopsis en-subtitle= kn-subtitle= en-abstract= kn-abstract=FE UPTAKE-INDUCING PEPTIDE1 (FEP1), also named IRON MAN3 (IMA3) is a short peptide involved in the iron deficiency response in Arabidopsis thaliana. Recent studies uncovered its molecular function, but its physiological function in the systemic Fe response is not fully understood. To explore the physiological function of FEP1 in iron homoeostasis, we performed a transcriptome analysis using the FEP1 loss-of-function mutant fep1-1 and a transgenic line with oestrogen-inducible expression of FEP1. We determined that FEP1 specifically regulates several iron deficiency-responsive genes, indicating that FEP1 participates in iron translocation rather than iron uptake in roots. The iron concentration in xylem sap under iron-deficient conditions was lower in the fep1-1 mutant and higher in FEP1-induced transgenic plants compared with the wild type (WT). Perls staining revealed a greater accumulation of iron in the cortex of fep1-1 roots than in the WT root cortex, although total iron levels in roots were comparable in the two genotypes. Moreover, the fep1-1 mutation partially suppressed the iron overaccumulation phenotype in the leaves of the oligopeptide transporter3-2 (opt3-2) mutant. These data suggest that FEP1 plays a pivotal role in iron movement and in maintaining the iron quota in vascular tissues in Arabidopsis. en-copyright= kn-copyright= en-aut-name=OkadaSatoshi en-aut-sei=Okada en-aut-mei=Satoshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=LeiGui J. en-aut-sei=Lei en-aut-mei=Gui J. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HuangSheng en-aut-sei=Huang en-aut-mei=Sheng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MaJian F. en-aut-sei=Ma en-aut-mei=Jian F. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=MochidaKeiichi en-aut-sei=Mochida en-aut-mei=Keiichi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=HirayamaTakashi en-aut-sei=Hirayama en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Group of Environmental Stress Response Systems, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Group of Plant Stress Physiology, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Group of Plant Stress Physiology, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=4 en-affil=Group of Plant Stress Physiology, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=5 en-affil=Group of Plant Stress Physiology, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=6 en-affil=Crop Design Research Team, Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=7 en-affil=Group of Environmental Stress Response Systems, Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=oestrogen induction system kn-keyword=oestrogen induction system en-keyword=fep1-1 kn-keyword=fep1-1 en-keyword=iron-deficiency response kn-keyword=iron-deficiency response en-keyword=transcriptome kn-keyword=transcriptome END start-ver=1.4 cd-journal=joma no-vol=12 cd-vols= no-issue=1 article-no= start-page=6236 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=20211029 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structural basis for high selectivity of a rice silicon channel Lsi1 en-subtitle= kn-subtitle= en-abstract= kn-abstract=Silicon (Si), the most abundant mineral element in the earthfs crust, is taken up by plant roots in the form of silicic acid through Low silicon rice 1 (Lsi1). Lsi1 belongs to the Nodulin 26-like intrinsic protein subfamily in aquaporin and shows high selectivity for silicic acid. To uncover the structural basis for this high selectivity, here we show the crystal structure of the rice Lsi1 at a resolution of 1.8 ?. The structure reveals transmembrane helical orientations different from other aquaporins, characterized by a unique, widely opened, and hydrophilic selectivity filter (SF) composed of five residues. Our structural, functional, and theoretical investigations provide a solid structural basis for the Si uptake mechanism in plants, which will contribute to secure and sustainable rice production by manipulating Lsi1 selectivity for different metalloids. en-copyright= kn-copyright= en-aut-name=SaitohYasunori en-aut-sei=Saitoh en-aut-mei=Yasunori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=Mitani-UenoNamiki en-aut-sei=Mitani-Ueno en-aut-mei=Namiki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SaitoKeisuke en-aut-sei=Saito en-aut-mei=Keisuke kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MatsukiKengo en-aut-sei=Matsuki en-aut-mei=Kengo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HuangSheng en-aut-sei=Huang en-aut-mei=Sheng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=YangLingli en-aut-sei=Yang en-aut-mei=Lingli kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=IshikitaHiroshi en-aut-sei=Ishikita en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=ShenJian-Ren en-aut-sei=Shen en-aut-mei=Jian-Ren kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=SugaMichihiro en-aut-sei=Suga en-aut-mei=Michihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Research Center for Advanced Science and Technology, The University of Tokyo kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=6 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=7 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=8 en-affil=Research Center for Advanced Science and Technology, The University of Tokyo kn-affil= affil-num=9 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= affil-num=10 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=11 en-affil=Research Institute for Interdisciplinary Science, Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=71 cd-vols= no-issue=6 article-no= start-page=1792 end-page=1800 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191130 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Decrosslinking enables visualization of RNA-guided endonuclease-in situ labeling signals for DNA sequences in plant tissues en-subtitle= kn-subtitle= en-abstract= kn-abstract=Information about the positioning of individual loci in the nucleus and the status of epigenetic modifications at these loci in each cell contained in plant tissue increases our understanding of how cells in a tissue coordinate gene expression. To obtain such information, a less damaging method of visualizing DNA in tissue that can be used with immunohistochemistry is required. Recently, a less damaging DNA visualization method using the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/associated caspase 9) system, named RNA-guided endonuclease-in situ labeling (RGEN-ISL), was reported. This system made it possible to visualize a target DNA locus in a nucleus fixed on a glass slide with a set of simple operations, but it could not be applied to cells in plant tissues. In this work, we have developed a modified RGEN-ISL method with decrosslinking that made it possible to simultaneously detect the DNA loci and immunohistochemistry signals, including histone modification, in various types of plant tissues and species. en-copyright= kn-copyright= en-aut-name=NagakiK. en-aut-sei=Nagaki en-aut-mei=K. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YamajiN. en-aut-sei=Yamaji en-aut-mei=N. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=Centromere kn-keyword=Centromere en-keyword=CRISPR/Cas9 kn-keyword=CRISPR/Cas9 en-keyword=epigenetic modifications kn-keyword=epigenetic modifications en-keyword=immunohistochemistry kn-keyword=immunohistochemistry en-keyword=in situ DNA visualization kn-keyword=in situ DNA visualization en-keyword=RNA-guided endonuclease-in situ labeling (RGEN-ISL) kn-keyword=RNA-guided endonuclease-in situ labeling (RGEN-ISL) en-keyword=telomere kn-keyword=telomere END start-ver=1.4 cd-journal=joma no-vol=70 cd-vols= no-issue=10 article-no= start-page=2717 end-page=2725 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190506 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The tonoplast-localized transporter OsHMA3 plays an important role in maintaining Zn homeostasis in rice en-subtitle= kn-subtitle= en-abstract= kn-abstract=In order to respond to fluctuating zinc (Zn) in the environment, plants must have a system to control Zn homeostasis. However, how plants maintain an appropriate level of Zn during their growth and development is still poorly understood. In this study, we found that OsHMA3, a tonoplast-localized transporter for Zn/Cd, plays an important role in Zn homeostasis in rice. Accessions with the functional allele of OsHMA3 showed greater tolerance to high Zn than those with the non-functional allele based on root elongation test. A 67Zn-labeling experiment showed that accessions with loss of function of OsHMA3 had lower Zn accumulation in the roots but similar concentrations in the shoots compared with functional OsHMA3 accessions. When exposed to Zn-free growing medium, the concentration in the root cell sap was rapidly decreased in accessions with functional OsHMA3, but less dramatic changes were observed in non-functional accessions. A mobility experiment showed that more Zn in the roots was translocated to the shoots in accessions with functional OsHMA3. Higher expression levels of OsZIP4, OsZIP5, OsZIP8, and OsZIP10 were found in the roots of accessions with functional OsHMA3 in response to Zn deficiency. Taken together, our results indicate that OsHMA3 plays an important role in rice roots in both Zn detoxification and storage by sequestration into the vacuoles, depending on Zn concentration in the environment. en-copyright= kn-copyright= en-aut-name=CaiHongmei en-aut-sei=Cai en-aut-mei=Hongmei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=HuangSheng en-aut-sei=Huang en-aut-mei=Sheng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=CheJing en-aut-sei=Che en-aut-mei=Jing kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=2 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=3 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=4 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= affil-num=5 en-affil=Institute of Plant Science and Resources, Okayama University kn-affil= en-keyword=OsHMA3 kn-keyword=OsHMA3 en-keyword=vacuolar sequestration kn-keyword=vacuolar sequestration en-keyword=ZIP transporter kn-keyword=ZIP transporter en-keyword=Zn distribution kn-keyword=Zn distribution en-keyword= Zn root-to-shoot mobility kn-keyword= Zn root-to-shoot mobility en-keyword=Zn tolerance kn-keyword=Zn tolerance END start-ver=1.4 cd-journal=joma no-vol=6 cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2015 dt-pub=20150105 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=AtPHT4;4 is a chloroplast-localized ascorbate transporter in Arabidopsis en-subtitle= kn-subtitle= en-abstract= kn-abstract=Ascorbate is an antioxidant and coenzyme for various metabolic reactions in vivo. In plant chloroplasts, high ascorbate levels are required to overcome photoinhibition caused by strong light. However, ascorbate is synthesized in the mitochondria and the molecular mechanisms underlying ascorbate transport into chloroplasts are unknown. Here we show that AtPHT4;4, a member of the phosphate transporter 4 family of Arabidopsis thaliana, functions as an ascorbate transporter. In vitro analysis shows that proteoliposomes containing the purified AtPHT4;4 protein exhibit membrane potential- and Cl-dependent ascorbate uptake. The AtPHT4;4 protein is abundantly expressed in the chloroplast envelope membrane. Knockout of AtPHT4;4 results in decreased levels of the reduced form of ascorbate in the leaves and the heat dissipation process of excessive energy during photosynthesis is compromised. Taken together, these observations indicate that the AtPHT4;4 protein is an ascorbate transporter at the chloroplast envelope membrane, which may be required for tolerance to strong light stress. en-copyright= kn-copyright= en-aut-name=MiyajiTakaaki en-aut-sei=Miyaji en-aut-mei=Takaaki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KuromoriTakashi en-aut-sei=Kuromori en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TakeuchiYu en-aut-sei=Takeuchi en-aut-mei=Yu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=YamajiNaoki en-aut-sei=Yamaji en-aut-mei=Naoki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=YokoshoKengo en-aut-sei=Yokosho en-aut-mei=Kengo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=ShimazawaAtsushi en-aut-sei=Shimazawa en-aut-mei=Atsushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SugimotoEriko en-aut-sei=Sugimoto en-aut-mei=Eriko kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=OmoteHiroshi en-aut-sei=Omote en-aut-mei=Hiroshi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=MaJian Feng en-aut-sei=Ma en-aut-mei=Jian Feng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=ShinozakiKazuo en-aut-sei=Shinozaki en-aut-mei=Kazuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=MoriyamaYoshinori en-aut-sei=Moriyama en-aut-mei=Yoshinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= affil-num=1 en-affil= kn-affil=Advanced Science Research Center, Okayama University affil-num=2 en-affil= kn-affil=Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science affil-num=3 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=4 en-affil= kn-affil=Institute of Plant Science and Resources, Okayama University affil-num=5 en-affil= kn-affil=Institute of Plant Science and Resources, Okayama University affil-num=6 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=7 en-affil= kn-affil=Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science affil-num=8 en-affil= kn-affil=Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences affil-num=9 en-affil= kn-affil=Institute of Plant Science and Resources, Okayama University affil-num=10 en-affil= kn-affil=Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science affil-num=11 en-affil= kn-affil=Advanced Science Research Center, Okayama University END